sailboat tech why lithium batteries

Sailboat Tech – Lithium Batteries & Why We Chose Them

There is an old saying that batteries don’t die, they are killed.  Sadly, this is true and we are guilty as charged.  Ba-dum-bum-CHING!  Sorry, I couldn’t help myself.

In all seriousness, we not only killed our first set of RV batteries, we tortured them daily and finally froze them to death. Why?  We didn’t know any better.  Without fully understanding how batteries work coupled with not having a battery monitoring kit, we were clueless, but that’s another story.

Fast forward seven years of trial and error and we’re practically off the grid pros.  Ok, that may be a stretch, but we have become finely tuned into the resources we use and how to replenish them.  Especially when it comes to our power needs.

Now that we are living aboard a sailboat, electricity has become our most important resource.  I know that sounds crazy considering we use wind power to move our floating home but stick with me here.

It seems like everything aboard our catamaran requires electricity to function.  Systems such as radios, instruments, autopilot, lights, bilge pumps, and winches are all powered by electricity.  Add in our refrigerator, freezer, water heater, air conditioning, cooking devices, cameras and so on…we practically need our own mobile power plant!

Or… A stellar set of lithium batteries.

Lithium batteries are by far the most important electrical upgrade on our sailboat.  They are the heart of our power system supplying juice to each of our devices, just like our heart pumps blood through our bodies to vital organs.

Everything on our sailboat runs off the battery bank, not only while anchored out but also while sailing with the engines off.  Having a sufficient battery bank to supply those power needs is incredibly important.  Having all the fancy electronics in the world on our boat won’t matter if we can’t power them.

Most Important Sailboat Tech Upgrade

That’s why we say lithium batteries are the most important upgrade on our boat.  Once we’ve got solid power, then we can start thinking about all the fun stuff they can power.  So, choosing lithium was a no brainer.

We made this video to help demonstrate why we think lithium batteries are awesome and why we chose them.  Fair warning, this is not a full-on technical analysis.  We’re not experts, we’re two average people sharing our experiences and what we’ve learned along the way.

We hope that made some sense?!  Below is a more organized version along with extra details we talked about.

Oh, and if you are wondering about my vacuum or Jason’s lithium drill, we do love them both and you can find them here:

Why Lithium vs AGM?

There is simply no comparison.  Lithium batteries are leaps and bounds better, stronger, lighter, smaller, faster, safer, easier, greener, and more powerful than lead-acid or AGMs. Period.  So why does anyone still buy them?

Money Talks

Price.  There is a common misunderstanding that lithium is drastically more expensive than AGMs or lead-acid batteries.

But first things first.  Let’s eliminate flooded lead-acid as an option.  Lead-acid batteries used to be the best and only option but we feel it has absolutely no place on a boat anymore.  Toxic off-gassing, storage issues (must be stored in a nonliving area, upright in a well-ventilated area) maintenance (topping off liquids once a month), lack of efficiency, and safety risks make it a no go in today’s technology-filled world.

We feel so strongly about this, we even swapped out our engine and generator batteries for lithium.  You know, because they are stored right under where we sleep!  How could we sleep well-knowing lead-acid batteries were off-gassing toxic fumes under our mattress.

So that leaves us with AGM and Lithium as viable options.  At first glance these batteries seem fairly similar: They are both “8D” size, the amp hours are similar…sure the AGM weighs about 40% more but the lithium battery looks grossly overpriced in comparison to the AGM.  The sticker shock is enough to send anyone running, and trust me that is EXACTLY what we used to think.

lithium vs agm for sailboat

The problem here is the AMP hour conundrum.  Lithium batteries are sooo drastically different from AGM and there is way more to consider than just the factory rated AMP hours printed on the spec sheet.

Useable AMP Hours

For our example, we’re looking at a Relion Lithium Battery (because that’s what we have) vs a Lifeline AGM Battery.

What we really need to be looking at when comparing any batteries is the useable amp hours, not the amp hours printed on the battery.

lithium vs agm batteries

Looking at the useable amp hours we can clearly see that the AGM battery has almost half the useable amp hours of the lithium.  So, to get a similar amount of useable amp hours we would need two AGM batteries to equal our one lithium battery.

Life Expectancy

The next big distinguishing factor between AGM and lithium batteries is the life expectancy.  Lithium lasts at least twice as long as an AGM (and most likely triple and beyond).  That means we would go through at least double the amount of AGM batteries during the lifespan of our lithium bank.

lithium vs agm batteries

Looking no further than this, it’s easy enough to see that we would need at least four AGM batteries to have similar usage as our one lithium over time. So not only is that a lot more weight and space taken up, but now our price is now practically the same (probably cheaper if you consider installation costs times two).

best batteries for off the grid

Technically it should be the size and weight of 2 AGM’s because you would be replacing batteries at the halfway point. I was a little hasty here but you get the idea.

But let’s not stop there, because lithium still has a lot of bragging to do.  Here are some of the other perks we get by going with lithium:

  • Super Model Skinny – Lithium is almost half the weight of lead-acid and takes up way less space per useable amp hour.  This means more battery in less space…without the drama.
  • How Low Can You Go – Lithium batteries can be discharged down to 10% or lower. Most lead-acid and AGM batteries do not recommend more than 50% depth of discharge.  Overall battery life is seriously affected by higher levels of discharge in AGM (and lead-acid) yet only slightly affected in lithium batteries.
  • Mad Efficient -Lithium batteries are 99% efficient meaning that they allow the same amount of amp hours both in and out. Lead-acid batteries are less efficient and have a loss of 15 amps while charging and rapid discharging drops the voltage quickly and reduces the batteries’ overall capacity.  AGM batteries are slightly better than Flooded Lead Acid but nowhere near as good as Lithium.  (If you want to run high draw electronics like an Air Conditioner or water heater, you’ll want lithium batteries.)
  • Suck It Up Fast – Lithium Batteries have very little internal resistance and almost no absorb time so they can suck up power and charge all the way to 100% really fast. With old school batteries, there is a 3-stage charging cycle: 1. bulk phase where you push in a bunch of power to get the battery to 80-90% charged. 2. absorb phase where a charge is held back until the last 10% charge can be reached (this is because lead-acid have a lot of internal resistance at this phase). 3. float phase where the charge voltage drops because the battery is full. It’s that 2nd absorb phase that holds things up big time. It can take a really long time to get the last 10%…like hours.
  • Even Keeled – Lithium batteries maintain their voltage during use, which is better and more efficient for all our electrical devices.  Lithium doesn’t care if it’s at 30% or 95% DOD and they won’t lose capacity with heavier loads. This is especially important for things like AC, electric cooking devices, water heaters, etc. that pull a lot of power.  Lead-acid and AGM batteries will drop voltage consistently throughout the discharge cycle, they’ll need to be fully charged on a regular basis and heavy loads will quickly suck the life out of them.
  • Drama Free – Lithium requires no maintenance.  I can’t imagine pulling off our cushion, clearing out the storage, removing the shelves, and having to add distilled water (one more thing to have to carry and store) to all our batteries every couple of weeks or so.  That would be a horrible pain in the you-know-what, and another great reason not to buy lead-acid.


We’ve all heard about cell phones and computers with lithium batteries bursting into flames.  Scary (especially considering we carry these items in our hands) but this isn’t the same type of lithium.  Our lithium batteries are LiFePo4, it’s a different technology and it’s way safer.

Our lithium batteries have nifty circuitry built in that keeps the battery pack safe and under control. It’s called the battery monitoring system. Reputable lithium battery companies have lots of systems in place to make sure each battery has a BMS installed and is configured correctly.  We’ve seen firsthand what can happen when this very important step is ignored (that story coming soon).

Go For A Good Warranty

Whichever brand of battery you choose, make sure it has a solid warranty.  Also, make sure it’s from a company that is going to be around for a long while in case you ever need to take them up on that warranty.  Too many companies come and go leaving you stranded with no warranty and no customer service (sadly, we have experienced this).

Warranty was a big factor as to why we chose to install Relion on our sailboat. Relion Lithium Batteries come with a 5-year warranty.

Global Support

Another thing we had to consider when looking into batteries was global support.  We didn’t want to end up at some other point around the globe, have an issue and not be able to get support, service or warranty.  If you plan on traveling about the world as well, it’s something to think about when deciding which brand to go with.

Our Battery Bank

We have four 12V 300AH batteries for our house bank and a 12V 100AH battery for each of our engines.

Want a discount on Lithium Batteries?

Relion is offering 5% off to all GWTW Fans!  Just click the link below and it will be automatically applied at checkout.

Hello there! I honestly don’t know what to say, so I am going to tell you a bunch of random facts instead. I'm a fish eating vegetarian who hates spiders and loves snakes. I almost never took vacations growing up. I wanted to be Pippi Longstocking (still do). I misspell about every other word I write and still struggle with grammar. I love splurging on a good high tea (which is really hard to find these days). And whatever you do, don’t tell me I can’t do something, because then I'll HAVE to do it!

Comments (119)

  • Sean murrie

    Hi. Great vid guys. We wanted lithium batteries for our catamaran. But the marina electrician has said we can’t because our system is not compatible, and it will be very expensive to change it over. I believe they mean alternators, maybe the 12v-220v tranformer,not entirely sure. The boat was built in 2013. Any ideas?

    • Curious Minion

      Could be the alternator, the inverter, and/or your charge controller. The problem is that older gear was set up just to charge lead acid batteries, and so it has a charge profile that is specifically designed for that. Lithium batteries need a different charging profile. But 2013 isn’t that old, and if your electronic gear has a charge profile for AGM batteries that is usually close enough to a lithium profile that it will work. My suggestion is that you jot down makes & years of your alternator, inverter and/or charge controller. If you’ve already picked out a brand of lithium ion battery that you’d like to go with, call their tech support guys and ask them if your gear is compatible or not. They’ll let you know what will or won’t work. If your gear isn’t compatible, ask them specifically what you need to look for in a replacement. As a ballpark number, we recently talked about this change on our boat and figured it would cost us $15,000 for a new inverter, alternator, and 600aH of LiOn batteries. That is indeed “very expensive” by most peoples’ standards but weight savings and other advantages of LiOn are impossible to beat at the moment. And if your lead acids and/or alternator are nearing the end of their life cycle anyway it starts to make even more sense. Once you have LiOn you won’t regret it. Good luck with it!
      Curious Minion

      • Sean Murrie

        Hi, and thanks for your reply. We will look into this further! Much appreciated

  • Greg D

    Hi Nicki and Jason,

    I do think there are inherent risks in carrying Lithium ion batteries around the world and I was concerned about putting this technology on my boat for our annual Bahamas cruise. We added 2kw of solar but don’t have enough storage, even with more AGM’s. I was really concerned about adding Lithium ion, since if they catch on fire there is no really good way to put them out. Flooding them with water does not seem to be a good option and my batteries sit in a compartment above my fuel tank.

    Then I watched your video on swimming at night with sharks and Nicki said something that stuck with me. Life is about taking risk from the time we are born. As an electrical engineer I should be more willing to take risk, as I know all the things that can go wrong with the electrical system and how to monitor them, but it was Nicki swimming with sharks and her explanation of risk that finally convinced me to go ahead and change out all my AGMs for Lithium Ion Phosphate. Now if the boat catches on fire and we are swimming with sharks we might get both experiences!!

    One question I have for Nicki and Jason is do they plan to head south to New Zealand now they are all the way North in Tonga. If so the timing will be critical as those waters can be very unfriendly with waves and conditions I have not yet seen in your videos. A lot of cruisers seem to end up in the Bay of islands in New Zealand and never leave.

  • Doug Zavitz

    I am an 80 year old past fultimer, My departed wife and i were fulltimers in an 1970 MCI 6 converted by us it was the most fufilling part of lives. What you are doing is is magnificient we also did some sailing oops monohull and some trips to Bahamas and Exumas in a 40 foot trawler with friends ( were still friends) , Nikki does remind me of my wife bright smile and lets do it view, Keep it up……..forever if u can… some fun things we can pass on my wife would always stir up a campfire when asked what was the most unusual thing about our travels and her answer “Ive had sex in 38 states and six provinces” or when someone would say we would love to do what your doing we would answer with what do you want to give up…..If I were younger I would sign on for crew

  • Rick Nicholson

    I truly want to love Lithium batteries, I certainly use them in a host of things from snow blower to tools, to electronics etc. But in a source I have since lost, the author basically says, ignore the blocks and most of what you read about lithiums, they aren’t quite there yet, and despite what you read, lithiums still can combust. What I would be curious about is a comparison of Firefly Oasis batteries (made by Caterpillar) versus Lithium. Many of the positive attributes of lithium are also true with Fireflies. Fireflies can be abused, not fully charged, taken down below 20% use (manufacture recommends down to a 20 % discharge, but many have gone below that and say they still are chugging along). And they are cheaper, about 2/3rd’s of the cost of lithium.

    • Curious Minion

      Okay, let’s first tackle the Lithium ion safety myth, because Lithium Iron Phosphate, the chemistry for larger RV, house, and boat batteries, are remarkably safe. The Samsung cell phone batteries that garnered so much attention are a completely different chemistry with different risks. Per Battery University (a respected online info source):
      the National Oceanic and Atmospheric Administration say that your chance of being struck by lightning in the course of a lifetime is about 1 in 13,000. Lithium-ion
      batteries have a failure rate that is less than one in a million.
      Yes, there is a very tiny risk and it is most often associated with overcharging or charging when the battery itself is below freezing temperatures. So if you correctly configure your charge controller and are aware of the temps in your battery compartment, you can take your Li-ion fire risk effectively to zero.

      As for advantages, these factors have to be weighed by each individual to decide what works best for you. If safety is your #1 concern, I think proper use negates that whole argument. I have had Li-ion batteries in my motorhome for 3 years now and have never once worried about a fire risk. If your #1 concern is up-front cost, then carbon foam is your best choice. If you compare the Firefly group 31 at 110 amp hours ($512 retail) and the Battleborn 100 amp hour (I recently saw them at an RV show for $900), over the lifetime of the battery you’ll need to buy 2 or possibly 3 Fireflys (lifespan of 3 years) to cover the same period of use as a single $900 Battleborn (lifespan of 10+ years). So if you don’t push the carbon foam hard on a regular basis, cost might be a wash. If you tend to deeply discharge your battery on a regular basis, then you’re more likely to need that 3rd carbon foam to cover the same lifespan of a single li-ion. If your #1 concern is reducing weight, Li-ion is a no-brainer, with a Battleborn weighing about 28 pounds and the Firefly coming in at 75. If you live on a catamaran where weight is a big concern and weight *distribution* is an even bigger concern, then it’s hands-down li-ion. For just a few more pounds you could install 3 100 amp hour Battleborns for the weight of a single 110 ah Firefly. Now we get to the more nebulous factors. Let’s first look at charging speed. Yes, a carbon foam battery takes an initial charge much faster than a SLA battery, but it still requires a slow absorb to get to full charge, whereas a li-ion will charge at full rate right up to 100%. Again, if you are living full time off-grid *and you regularly need to run a generator to charge your batteries*, then li-ion is also going to save money because you’ll be running your generator far less to charge your batteries. To put the last 10% into an SLA or carbon foam battery could take several hours of generator time, and at $3/gallon for gas and a gallon/hour for most generators, that $$ will add up fast. Now if you have a large enough battery bank that you don’t need to get to 100% every day to meet your lifestyle power needs, then carbon foam will work very well (although to get the longest lifespan from them, charging to 100% every now and again is still necessary, whereas Li-ion don’t care if they never make it to 100%). And lastly, there’s the reduction in voltage that happens with carbon foam (and SLA) batteries as they become depleted. I remember back to my days of SLA batteries when I couldn’t run the microwave (or other high-draw appliances) if my batteries were below 50% charge, whereas my Li-ion batteries will run my microwave even when they’re at 25%.
      So IMHO, if you live full time off the grid and you plan on keeping the same battery system (or can move it with you to your next home), I believe that Li-ion is a better value in the long run. If you buy a different “home” every few years, then maybe carbon foam makes more sense. But regardless of your lifestyle, I don’t think safety should be a concern. Lithium Iron Phosphate chemistry is extremely safe unless you abuse it.
      Whew! Hope that helps.
      Curious Minion

  • Allan "RocKiteman" Gaines

    “…guilty as charged”?!

    Do you know how re-VOLTING that pun is???

    {I’ll see myself out now…😊}

  • Jeff & Debby S/V Making Memories

    Great video! Thanks for doing this.
    Did you find a monitoring system that works with the ReLion’s. We are close to buying them for our retrofit, but I can’t get past the idea of no information on the battery health. Thanks!

      • Deran Eaton

        Nikki, Jason,

        If you ever have “Curiosity” cross the Equator again, this time at the International Date Line, please let me know and I’ll make an Emerald Shellback award for “Curiosity’s” salon wall.

        I know you’re not experts, but “Curiosity” being about learning — hopefully without killing the cats — 😉

        FYI #1: “LiFePo4” is better written as “LiFe(PO)4” — subscripting the 4, for lithium iron phosphate. “Po” on the Periodic Table is polonium (two steps between radon and lead). Polonium has some radioactive isotopes with a nasty habit of showing up in municipal ground water systems ashore, depending on the locality. Elemental lithium, like the other alkali metals (left column of the Periodic Table), also tends to explode upon contact with water. No problem so long as the cells don’t rupture. Hope this doesn’t keep you awake at night like the lead-acid cells’ maintenance would.

        FYI: #2: What drives the lithium battery solution is the economics of energy density — how much useful energy (in this case, electric power) can be packed into a given physical space for the mass and cost to do so — knowing some costs are “opportunity costs”. Designed from scratch, an “off grid” system generally requires reducing your loads before sizing your source (plus 20%-30% budgeted for future loads added). A load with multiple devices and their respective voltages requires using Ohm’s Law (power = volts X amps) X time ON to compute aggregate power used/predicted in Watt-hours (or KW-hrs, as the landlubbing audience sees on their electric bill).

        FYI #3: Having a power gauge like the Xantrex definitely helps indicate battery charge, but is NOT the final indicator for “battery health”. Batteries having internal charge management circuits (practically required with lithium cells) will electrically isolate a failing cell, making its energy unavailable to the system even when the power gauge says the entire bank is full. The gauge or meter only reports what it’s designed to detect. System memory (optimum new versus entropy over time/use) is required for “battery health” diagnostics, and not all power gauges have this.

        FYI #4: Solar cell manufacture often requires the same materials and processes used to make semiconductors and printed circuit boards. That includes some rather toxic things which are either built into the product, or solvents recovered for reuse until saturated — like stereolithography etching acid baths and arsenic as an electron biasing dopant (though some research is starting to use nitrogen more in certain devices). Even lead still has value in stabilizing electronic solders against tin whiskering. There are two points here:
        1) Some of the so-called “green” technologies aren’t as “green” as their makers and advocates would have one believe — because there is no such thing as a “free lunch”. Though most of it doesn’t reach us, the Sun emits harmful radiation like any terrestrial nuclear reactor. That’s what solar power really is: Nuclear energy harvested at a distance.
        2) As your trial and error experience shows, true cost-vs-benefit analysis measures what is gained by what the costs really are. Mobility and portability are the two best arguments for renewable energy sources afloat, but as you’ve discovered the better utilities and necessities need much more power than the weather-dependent renewables can deliver routinely by themselves — starting with enough clean fresh water. Energy density drives that discussion, too.

        Fair winds, following seas,


        • Rick Wallace

          FYI on FYI#2: Ohms law is V=IR (volts=amps*ohms) – hence the ‘Ohms’ part named after Georg Ohm who discovered it. You are describing Joule’s law, which is P=IE (power=amps*volts) and is named after James Joule. So, it’s not Ohms law, it’s Joule’s law. Seeing as we’re into FYI’s. 🙂

  • Eric Vahlbusch

    Oh really? Nice video, nice post. But your math really does not work out. Consider; 6 ReLion Grp 31 100AH each, $1300 each, or $7800 (plus shipping) to get a 600AH Bank. 5 Rolls Grp 31 AGM 128AH, $272.00 each. or $1560 (including shipping) to get a 600AH bank The lithiums are 500% more than the AGMs. We installed these same batteries in our 35 foot sailboat in 2011 and it is now time to replace them, 7 years of perfect service. We charge with solar, 100amp alternator off our Yanmar, and a generator if we need it which we hardly ever use. There is no possible way you can make this math work out, even if your argument is that we only need a 400AH lithium bank to achieve the same usable capacity as a 600AH AGM bank. Not to mention the fact that if you install lithium you need a new battery charger, a new monitor, a different alternator, etc. Lithium will likely be the way to go in the future, just like AGM was going to be the way to go at one point. You are paying premium prices for being on the bleeding edge and while there is nothing wrong with that if you can afford it, most of us don’t have the luxury of paying exorbitant prices for something that in five years will actually be more cost effective. My last comment is meant to be respectful, because everyone who cruises has their own way of doing things. But compared to most I believe you guys are power hogs, in relative terms. When we refit to go long distance cruising, from sailing on weekends, we spent two full years redesigning, rebuilding, remodeling and one of our foremost thoughts was power and water management. Our AH budget is 100 per day, and many days we use far less than that. Our reefer is insulated to R value 40, except on the bottom where it is 50. We use less than 2 amps per hour for refrigeration at an ambient air temp of 85 degrees. I am betting you use triple that or more. Anyway your video was very interesting, I just think that anyone willing to pay the premium prices for lithium plus conversion costs would be better off waiting 5 years and using the money saved to buy more wine.

    • David Newell

      I must say you made me smile… One little question, how much did your ‘cruising refit’ cost per amp consumption saved? Just asking.
      The average life of an AGM bank is approximately 4 years and therefore the life expectancy for 50% of owners is less than 4 years. Also, few if any AGM/LA banks are properly and regularly, fully charged, with experienced, knowledge cruisers getting 35% usable amps per charge cycle.
      I know a marine electrician who has used, studied and regularly tested a 400 ah lithium battery for five years. He has amassed over 700 cycles. The battery still tests at over 400 amp/hrs when fully charged. Nice ! Looks like 2000 cycles is a conservative expectation of useful life expectancy.
      At the risk of belabouring the point, why would anyone want to carry an extra, ‘useless’ 500+lbs, on their boat. Also AGM and GEL LA batteries require the more sophisticated smart chargers and alternator management systems. Otherwise the banks will have a more reduced life cycle.
      There is more, but so little time. I failed to find a humourous way to present these points, but I did try…
      The Wynns are spot on winners, in my sometimes humble opinion. Be safe everyone…

    • Darin Rothwell

      Why would a battery of the same voltage rating need to have a new charger, monitor (lithiums have them built in, so basic monitoring should be the same, no?) and a different alternator. I could see if they went to from a 12V system to a 24V system where much of that would be true, but they specifically said they stayed on 12V to avoid running up the costs of an electrical refit.

      • PJ

        Different battery chemistries have different charge profiles. It is very important your battery chargers is set up for your battery type.

        Battery type, battery charger, alternator size, inverter size, cable size all needs to be in sync. Bad stuff happens when people simply upgrade the batteries assuming everything else will keep working.

  • Caley Ann Hand

    Great video on the lithium system. But you probably could’ve said that in the long run, comparing lithium and AGM batteries, the lithium is equal to 4 2/3rd’s AGM’s, which actually puts the AGM price over the lithium. the difference in Ah’s is 45 x DD = 90 x 2 lifetime = 180 Ah. Of course, that doesn’t even include all the peripherals needed to make an AGM system safe and usable. So the cost probably goes up another AGM battery; that’s 5 2/3rd AGM’s equals 1 lithium of the same capacity.

  • Lisa DeMarco

    Hi there! Have you considered using SimpliPhi batteries? 98% efficiency LFP batteries.

  • sven

    Hi Guys, Great presentation. Question: So with the 1200 amps of Lipo, for how long could you run your AC on that. And how many BTU’s do you have?


  • Joseph C. Picarequire

    Hum, I converted to LFpo4 6 years ago and it was an education. First they want to eat the alternator (small frame Balmars)which were not designed to output full Amperage for very long and the lithium don’t show resistance to the dumb alternator regulator Short story one allt. flamed out destroyed alternator. This dilemma forced the install of separate smart charger second gen regulator that could adjust alternators output down when the alternator frame temps increased beyond set point so new smart regulators and center fielder 2. $$$$. Another issue not mentioned is that these lfpo4 batteries can be damaged if kept on float at 100% SOC think being at a dock on shore power. . So they like best to be cycled. Also, if stored want best to be stored at 60% SOC. not 100% SOC which damages them. It is so important to lose the LA mentality and understand their unique characteristic and take advantage of them. Otherwise you can degrade (this happens insidiously and not noticed unless you do a draw down capacity test which is the only method to gauge their health and capacity. Balancing at the cell level is important if the drift. Another.point is that their SOC can NOT be estimated or correlated to voltage. The best you can do is to make use of a columb counter that is frequently synronized.
    So they require a full and carefull understanding and use to realize their full ROI potential.

  • Frank

    What brand of Lithium Battery did you buy? I want to do the same idea for my RV.

  • Bruce Griffin

    I was wondering if you went 12V instead of 24V or 48V or higher, because it was easier to find inverters or it was just easier to connect? I’m still RVing and was looking at how the Volta Power System was designed. At first I thought yeah sure on their claims, then another Wanderlodge owner built his own 48V system and has proven to me it is possible to run 3 roof AC units with it.

    • Curious Minion

      For both RVs and sailboats, there are lots of appliances & systems (like the furnace) that are 12V, and RV chassis are wired with 12V. So it’s just easier to stick with 12V than it is to convert everything.

      • Bruce Griffin

        What I’m seeing is that people are using 48V DC storage to the inverter then a DC-DC converter for the 12V systems. The 48V is suppose to allow the inverter to be more efficient to make the 120V AC. I understand some of the newer electric cars are going higher than 48V now as well to improve performance and range.

  • Many thanks for the info and the effort you guys went to to put this out! We’re looking at doing a lithium upgrade on our catamaran once we hit Australia for the off-season so I’m going to throw a few more technical questions at you. 🙂

    Did you also do anything for the charging systems on Curiosity? Since lithium has a different charging profile to AGMs, we’re looking at upgrading our inverter/charger, alternators and solar controllers. Unfortunately, those aren’t cheap upgrades and definitely cut into the price/lifecycle benefit of lithium.

    My other big concern is a situation with a BMS shutdown and an alternator running, resulting in an open circuit situation and the likely destruction of the alternators. Most solutions I’ve seen involve keeping an AGM battery or two somewhere in the battery set up that could take the charge if the lithiums go off-line. Did you have to do anything special since you went to an all lithium set up?

    Thanks again and hope to see you out here!

    • Curious Minion

      Hey David. Hopefully Jason will chime in here too, but I don’t think you have anything to worry about on either account. Let’s tackle each part.

      Re: changing out the solar controller, etc. You should check with your battery manufacturer when you’ve decided on a brand, but you shouldn’t need to change out any of the existing gear (as long as it’s relatively modern). Most drop-in lithiums are compatible and by design will happily charge on the same settings as AGM. You’ll need to tweak the settings on the solar controller, but your battery supplier and the solar controller support team should be able to walk you through all of that. If your inverter, etc. are older then I’d suggest talking to customer support for the brand of batteries you’re buying and ask them about compatibility/known issues. [You can also try support for the inverter, etc.] ReLion support was super helpful during our switch from SLA to LiFePO4 (and we’ve had no issues in nearly a year of use since the switch, including our 15 year old inverter).

      On to the alternator. Again, if your alternator is relatively modern, this shouldn’t pose a problem. Remember that the lithiums aren’t the only load on the alternator, as you will almost certainly have other 12v systems drawing (fans, lights, fridge, etc.). We know other full-time RVers who’ve converted to Lithium, do not have AGMs to take a charge, and have never had an issue. This includes RVs that are brand new, 15 years old, and even a classic 1960’s bus conversion. If in doubt, always check with the battery manufacturer as they’re the experts on their product. On a related note, if your boat and systems are older you might want to make sure that all your fuses and switches are in good condition and able to handle the load.

      • First of all, may I just say that Curious Minion is a fantastic internet name. 🙂

        Unfortunately for me, our solar controllers aren’t programmable for lithium. Not my best purchase when outfitting and why I’m looking at a swap. We don’t have quite as much solar as Curiosity, but we do our best to live off solar as much as possible.

        For the alternators, I’m not sure if somehow an RV is wired up differently, but I’m fairly certain than on our boat at least, the alternators charge the batteries, then the batteries power all 12v systems. There is nothing 12v that the alternators power directly which is why I’m so concerned about what happens if the BMS takes the batteries offline. I’ve heard that there are ways to design a system with all lithium batteries that will take this situation into consideration, but I’m still trying to parse the good info from the bad. We have AGM start batteries on our boat for each engine which are still good so I think that’s solution I’m going to go with, but I like making informed decisions. 🙂

        Thanks for the help!

    • Hey David,
      We’re currently testing out an affordable 40a Stackable MPPT controller. I can’t give any info yet as it hasn’t hit the market. So far they are working great. If you have a couple months before your upgrade I think the BETA testing will be done and the product will be on the market.
      For the Inverter/Charger as long as you have a programmable inverter/charger you’ll be fine. We’ve used Magnum, GoPower and Mastervolt in the past. The thing I don’t like about Mastervolt (at least in the states) is they don’t have contact info for customer support. On the other hand you can call Magnum or GoPower direct and speak to a support technician to solve any issues you may have at sea. Victron also makes great products, possibly the most “techie-cool” of all the inverter charger companies.
      If your BMS shuts off your batteries you will need to ‘wake’ them. First off, you don’t want to let your batteries get to 30% or below so in theory a BMS shut-down should never happen if you have a proper battery monitor. In the rare case you might have to wake your batteries there are two options I know of: 1) Buy a small battery jump starter, you know like the ones for jump starting a car. It needs to be “dumb” as the more expensive brands have electronic circuitry built in that won’t allow them to work with lithium. 2) Jump the house bank from the starter batteries. Sure it will spark, but it will wake your batteries and then you can charge them with the generator or engines.

      Hope that helps get you started in the right direction. There’s a lot of info out there, both good and bad, so I know it’s a pain to cut through it all. Feel free to ask any other questions here, happy to help.

      • Hey Jason, greatly appreciate the reply! We do have a programmable Victron inverter/charger, but it’s max charging output is 80amps. Our watermaker is 110v, requiring us to run our generator so having a larger capacity charger would be great to help fully top up the batteries. The shorter charge times for lithium seems like one of the big attractions so I’d like to take advantage of it.

        I’m assuming that the need to ‘wake’ up lithium batteries would come after a BMS shutdown due to low voltage? That would seem to make the most sense. What about the opposite situation? Do you have any concerns about what would happen in the event of a BMS shutdown due to high voltage?

        That is perhaps my biggest concern with a lithium swap as my alternators are currently the dumb stock ones that came with our Volvo engines, and I think they would likely suffer damage if they were running. I think we’ll probably just keep our AGM start batteries and deal with the issue that way, but as you said I’m still trying to find the good info as it would be nice to go all lithium at once and not piecemeal. 🙂

        • hmmmmm, if you’re Victron is working flawlessly it seems a waste to trash it…but yes, in theory you could put 100a in each battery, so a 4 battery bank could take 400a if the wiring, fusing and cable runs are all extremely beefy.
          If you’re alternators are spec then you’ll quickly realize they’re not putting any real amperage into your batteries, so overcharging is not a worry. Also most spec alternators won’t get your lithium batteries to a high enough voltage for optimum bulk charging. This really is a non-issue with drop in batteries like RELiON.
          There are some disadvantages to having AGM mixed with lithium. I spoke with Just Cats and RELiON in detail about this issue when researching our setup…sadly it’s info overload and I can’t recall the details.

          The best upgrade you could do IMO is swap the alternators with a high output system. It’s something we’ve kicked ourselves for not doing. A beefy alternator can put 300a into the battery bank, so in one hour the battery bank is charged! But, I understand your watermaker dilemma fully…so much like us you’re forced to run the gene no matter what. It’s not an easy decision and it’s a lot of money…but trust me: once you go with a lithium battery bank you will never consider SLA again.

          • Jason, many thanks again for all this info and answering my questions. There’s definitely a lot to learn about lithium but I think I’m narrowing in on the system design that will work best for us. Enjoy Panama and hopefully we’ll see you out here somewhere!

  • Though the BMS will protect the batteries, it will not protect your alternators if the BMS takes the battery offline when trying to protect it (high voltage etc), what are you doing to insure that the alternators and other charging devices are protected from an open circuit situation?. Also Lithium has a slightly charging regime and bracket for charging, they actually don’t want to be taken to 100%. Though the BMS ultimately protects the battery, the chargers and regulators should be lithium specific. The lithium battery will definitely make the alternators work harder and most standard alternators are not ready for that kind of loading, a temp sensor on the alternator with an external regulator specific to lithium would be recommended. Running heavy load ac devices like stoves and air conditioning etc. can draw a lot of power fast roughly 10 times when it comes to AC to DC conversion. So one air conditioner can draw 100-150 amps of DC per hour if running it off of the inverter, that will theoretically kill your house bank over night. Another point is if you are running your generator to just charge your batteries, the light load will kill that diesel engine prematurely over time. While a great idea for the house bank, I don’t think it is cost effective to use lithium for starting batteries necessarily since they don’t get cycled like a house bank. You could use a high quality agm like Odyssey for those and save a lot of money. Paralleling one of those batteries like the generator start to the house bank would immediately save charging devices from an open circuit situation.

  • Bill Hamilton

    You guys have been very helpful in assisting me in deciding which way to go with my, big, truck camper batteries. Limited space and I don’t want to carry any more weight than I need so Lithium is it. Now to calculate load that I’ll be using. Everything so far has been stingy on power… Thanks again

  • Anna Jonssn

    Hello, and thank you for a great run through of your battery set up. We are in the process of getting solar and batteries for our boat. Could you please tell me if your solar arsenal is enough? Do you find that it keeps the batteriet full when off the grid? Are the batteriets enough? Could you manage with less solar possbily? Could you manage with only three 300 batteries do you think? Due to space issue we can only fit 800 watts of solar on our boat (so maybe three batteris of 300 would suffice). We have no generator. My worry is that it will not be enough. We have basically the same wnats/needs in regards to power consption as you do. Please can you give me any info as t how much solar and batteries you could manage on if you had less space? Can you please talk more about your solar and batteries in future posts? It is so enlightning and I know you help so many of us with your technical and information dense posts. Thank you!

  • Diane

    Hi, very nice article and a great video – you two are funny & cute together and the video is informative! Just wanted to add a link to another blog article by a nomad couple who decided to switch to Lithium – Stef & James at The Fit RV. James goes into quite a bit of detail on what they had to do to get it all working in their Travato, but it didn’t go over my head even though I’m a total noob who knows nothing about this stuff:

  • JC

    Kinda odd, here I am researching batteries and lithium as well as Relion. I get to your post about them on your boat, and your efforts to get a discount without success….but Relion feels free to use your video on their marine page? interesting.
    Hope your getting a marketing fee for that…

    Have you also considered wind and water generators? I know the solar popularity in the RV world but wind/water seems ideally suited for a sailboat. Please elaborate on what modifications you mentioned for the charger/inverter? Does your current one have a position setting for Lithium or is it not needed on Relion? Thanks for blazing a trail on this.

  • Wow, now you got me thinking. I was just going to purchase on Monday, 2 6V 225A Lifeline AGM batteries for my motor coach (Justincredibles former 2004 Gulfstream BT Cruiser) … now you got me thinking … and hoping I win the lottery shortly … Those 2 AGM batteries are $295. a piece from … The reason I haven’t purchased them already, is that they’re each an inch longer that the battery brackets already on the side of the vehicle …. More research ….

  • marc myette

    Love your posts. However, I must disagree with your analogy regarding Lithium Batteries. Coming from an aviation background where this technology has been applied recently, I would offer the following observation. Lithium batteries are very unstable when not charged properly. They are prone to thermal runaway when not monitored precisely . Coming from the airlines who operate the Boeing 787, we have learned that battery monitoring must be practiced religiously . There is no room for error when caring for these batteries. It would be much safer and prudent to install 6 volt batteries to achieve the same power supply with greater safety and economics in a marine environment . Yes they are heavier, but AGM 6 volt would be much safer. The marine industry does not recommend these batteries for your application.

      • Chris H

        100% agree, Nikki, I think Marc is thinking of alternative types.

  • Michael

    Totally awesome job of research and explanation. Even to a technically-inclined individual, your presentation was just great. You guys have a real knack for it. You have made me do a rethink in support of another battery type coming out soon.

  • Hey guys! Thanks so much for the shout out. I thought I had already commented on this, but we were in the Bahamas – and as you are learning, the coverage is sketchy at best.
    We LOVE our batteries and are so happy we converted. Enjoy your journey – and now that we are temporarily back in the States, perhaps I will finally be able to watch some of your videos.

  • Damo

    Hey Nikki, Just a friendly correction for your “About the author” description. The word you are looking for to describe someone that considers them self a vegetarian BUT consumes fish is a pescetarian. The term vegetarian is reserved for those that do not consume the flesh of any animal, including sea life. Love what you do and keep it real 🙂

    • yes, but many people don’t understand the “pesca” so therefore in the interest of keeping things simple we just say vegetarian.

      • Damo

        Hey Jason, maybe, but you have a great opportunity to educate your audience rather than spread confusion about the subject, especially if you choose to use the term to promote what you do.

        For most being a vegetarian or vegan takes great focus, determination and a strong willingness to protect all life, our environment and their own health. When Nikki claims that she is a vegetarian and in fact not she is not, she is simply confusing those that do not understand the subject and claims a status that is not yet deserved.
        Being a vegetarian or Vegan is so much more than a simple food choice or cool label for a personal blog description. It reflects a highly-dedicated and often ridiculed person that has a unique understanding and respect for all life by not taking part in the killing and consumption of “any” animal. There is no real grey area to the subject. You either take part in the torture, murder and consumption of our animal friends or you do not. In this case Nikki does so using the term “vegetarian” is not only false but a complete contradiction and insult to the meaning of the word and to those that truly dedicate themselves to the no harm lifestyle.

        I too use to hunt, kill and consume fish until I slowed down and became mindful when going through the catching\killing ritual. Next time you hunt fish pay close attention to your sea life victim, first notice their stunning beauty and power, then notice the amazing struggle for life, the want to live is very strong with all life, then notice the panic, the fear, the reaction to the pain you inflict, quite often you will also notice the friends and family of that sea life helplessly following your victim\their loved one all the way to your boat of death (from their perspective of course). Then realise the choice you make to destroy one’s life for the sake of a tasty meal instead of using your power to protect those which cannot protect themselves. The difference between a vegetarian\vegan and omnivore human is huge and far from trivial.

        The answer to all this is simple, do what you do so well and educate your followers with truths and factual information or better still lead a life of no harm and kindness for all life and actually help make this world a better place for all life.

        Peace 🙂

        • Michael

          Excellent and accurate explanation. Thank you.

        • Wave

          Some good points but in that case why would most “vegetarians” with your rationale for not eating meat not eat meat from an animal that died from natural causes? Not criticizing your main point but seems like killing and consumption are different things. Peace!

      • Michael

        I don’t think it is any more difficult than lacto or ovo; as in lacto/ovo vegetarian.

  • Jim Langley

    I found y’all completely by accident while checking out an Oroville dam report on YouTube. You were a suggested post, glad I did, very informative & entertaining ! ! !

  • Jim Langley

    Remember when plasma screen tv’s were so expensive ? Then, they came out with lcd’s, led’s etc., now you can buy a 4k smart tv for what a Magnovox cost in the 60’s ! I think I’ll wait & see ! You have encouraged me closer to building my totally off-grid houseboat. .Thank you for the info

  • Robert Dyas

    It would be great to see a video explaining PSOC partial state of charge issues … another reason why real world Li battery life cycles are soooo much better than AGM.

    Also a video on Firefly carbon foam would be great. Slots between Li and AGM… probably what I will do next.

  • RJ

    Lithium batteries are an awesome choice. Yet it has to be understood that power management is crucial in any battery choice. Lead acid’s can be recovered, Lithium’s can be extended. Powering back to full charge each time reduces the life of a Lithium. The experiment on hand to increase the life of a Lithium, It is shown that charging only to 3.85 volts and using only to 3.4 volts can increase the D/C 5 times. To say, 500 D/C’s turns into 2,500 DC’s. A friend is looking into how to get to 5,000 D/c’s. Lithium’s, as I say are an awesome choice, Understanding Power Management, and using them correctly, is the key of these batteries.

  • John Lennie

    Thanks. Classicly funny but informative. Cheers.

  • Bob Sprengel

    Thought this might be of interest to you since you’ve sailed the Bahamas…

    Dragged Behind a Boat, Shedd Team Searches for Queen Conch in Bahamas

  • George Sears

    My gripe is that I would be paying a huge ‘first’ adopter’ premium for lithium that is configured into the RV market. The action is all in more energy dense batteries, generally 18650 batteries that go in Tesla products. But GM and LG make pouch cells, Tesla now makes a larger cell, and everything is aimed at making the electric auto price something like $100 per kWh. The prices you quote are almost 10x higher. The LiFePo, or the newer variants, are low density and they are considered ‘safer’. They have a long cycle life, at least in theory. But they are much heavier and much bigger. The Tesla Powerwall was offered in a 10 kWh configuration for $3500, which is $350 per kWh for a pack that is ready to mount.

    I just don’t understand the price discrepancy, although it’s clear the RV and boat markets and are small and very specialized. There are so many Gigafactories in the works right now, many in China, and the only goal of this investment is to get the price of electric car packs down as low as possible. The typical 200 mile range car will have 60 kWh. So at $100 per kWh, the goal, the pack costs $6000, at least for the cells. Right now if the price is $200, it is another $6000 for the car.

    For what you are doing it’s fine, but an RVer can look at a big solar install and a cheap generator, and just nurse some $90 Costco golf cart batteries along. It was very wet in Arizona this winter when I was down there in the trailer. I was amazed by how well the small generator worked, and the solar was a bust. It was still a battery system, 22 hours a day.

    So to me it’s nuts. It’s an old and heavy lithium formulation. The cells they use in ebikes are the Sanyo GA’s. That’s a 3.5 amp hour by 3.6v cell. You need 80 to make a kWh. They weigh 50 grams, so under 10 pounds for the cells. They can be robotically spot welded into packs. The weights you are ending up with seem a bit ridiculous. There’s a lot of structure, circuitry, safety stuff, but that should get simpler. They use an 8 ounce BMS in very large ebike packs.

    • swaan

      Sure the pricing is much better for residential and commercial products – that shouldn’t be any news to you 🙂

      The problem is marine use and not only thanks to it’s corrosive and humid nature. Fires on water are far more dangerous than on land. So far the other popular li-ion variants like NCA or NMC have not proven to as safe as LiFePo4, especially in thermal runaway situations. Sure the hazards can be contained (and they are in industrial use cases) but no marine grade off-the-shelf products exist yet.

      LifePo4 advances quite rapidly still – for commercial use I see noticeable positive changes every few years. I wouldn’t consider it old just yet. Google “Ampetus Super Lithium” for example and look at the warranted specs.

  • Shelby Jamison

    It’s good to have the right resources on board. Have you two looked at more than just solar to keep your bank charged like wind-chargers or a towed water turbine for when the weather isn’t cooperating?

  • Tom

    Hi guys. I really enjoy what you’re doing. You do a great job of presenting information without being too technical and keeping it light hearted. I’ve got one tiny little bone to pick… when you compare the weight of AGM’s vs Li, it isn’t quite fair to say 624 lbs vs 93 lbs. You’ve only got two AGM’s installed at a time, so shouldn’t it really be 312 lbs vs 93 lbs? Still a HUGE difference. Here’s to smooth sailing, good food, and great company!!

  • What a super fun & approachable overview of the cost advantages of lithium – great job guys! And I got a tickle out of seeing our name associated with RVers AND motorboaters. (That makes it just about as official as our Coast Guard Docs, I think).

    Installing solar and lithium on our new vessel is one of the top upgrades we’ll be approaching soon. So exciting to be diving back in deep to the current state of the industry. So much has improved since the olden days when we did our RV install nearly 6 years ago.

  • Great little overview and video. And cheers much for the shoutout too!


  • Michael

    These are great videos. We follow them routinely. But, with all due respect to those who have contributed, I don’t think I’ve read a straight answer to my earlier question, ” When you changed to lithium batteries, did you have to replace your existing battery charger (3 phase) or your inverter to accommodate the new lithium batteries”?

  • Jim

    thanks for the article on lithium which seems to be all the rage lately….we just installed 960w of solar on our mh and went with AGM batteries….we looked at the lithium option but decided not to move ahead with that option this time…maybe in 5 years or so. I think if you are a full time sailor or RV’r then lithiums are a no brainer…but for our use the AGM’s fit our lifestyle fine…thanks again for the article! Happy sailing 🙂

  • Chris B

    Thanks for the fantastic vid and documentation on your real-world experience with this tech. My next boat will definitely be lithium equipped. I just wanted to point out one little inaccuracy in your written comments above: you say, “But first things first. Let’s eliminate lead acid as an option” which isn’t exactly what you mean. All of the common battery types – Flooded, Gel, and AGM – are lead acid, with the lead and the acid arranged somewhat differently depending on the technology. So what you really meant to say was, “Let’s eliminate Flooded lead acid as an option”. Which I whole heartedly agree with. I can’t imagine how people have enough patience to deal with those things. I would think that to most people like us that would be the exact opposite of a viable option!!

  • Clive

    Fantastic video – entertaining and informative. While we wait for Elon Must to design a ship a marine-safe version of Power-Wall [heck, if he can power New South Wales in Australia in 100 days, how hard can it be?!], then the only other question I’d have regarding Lithium-Ion batteries is one of thermal safety. There have been some really scary Lithium Battery fires in the news [such as those on board the Boeing 787 Dreamliner, as well as countless different mobile phones.

    Do you have special precautions against thermal run-away? Do you use or would you consider cooling or fire suppressant in the compartment? Are there special recommendations for that?

    Also – I appreciate that your configuration is specifically geared towards off-grid power, but I’m curious to know whether or not you can “boost charge” your Lithium batteries whilst you are in a marine [i.e. from shore power] to give you a “full tank of juice” before leaving port? I see no reason why this would not be possible; just wondered if you’d considered it?

  • ed

    did i do the math correctly, $18,000 for the batteries

  • Well, I have to say, perfect timing for us on this one. We just shoved off about a month ago for our first bout of real cruising. We’d been living dockside for several months prior, with limitless shore power, and a few days ago found our DC power on the fritz. (Fridge a bit warmer, DC amper meter jumping around, certain devices not powering.) Then last night, after plugging in for the first time after about a week at anchor, we noticed the battery charger breaker wouldn’t stay flipped even while we were connected to shore power. We have an electrician coming out right as I type but needless to say I think we have too, sadly, abused, tortured, and killed our house batteries. I feel slightly better knowing y’all learned that lesson yourselves on the RV years ago–misery loves company, I guess?

    Thanks for all of the info here, it’s been illuminating to me as someone who knows next to nothing about the electrical parts of this boat. And also for all the info on the lithium batteries. I knew exactly none of that prior to reading, including the toxic output of the lead acid batteries. Yuck.

    Question, do y’all happen to know whether switching to lithium batteries (from 4 12V lead acid batteries) would require reworking our solar panels? Not sure if that’s too far off topic and/or if you’d need a bunch more info re our solar to answer but thought I’d ask just in case!

    Take care and thanks, as always, for the thoughtful, informative posts!

    • swaan

      There are many components to a solar set up but generally speaking the panels do not need to be changed. Panel wires might need to be moved around.

  • Bob

    Very well presented! You guys certainly seem to have your power needs covered and sorted. I do think, however, that I might have saved myself some money (without worrying about performance) by going with AGM for the starting batteries. Anyway, that money has already been spent, and I’m sure you’re happier with the all-lithium arrangement. Looking forward to the next tech episode, and I’d still like to see that davit system in operation. Never seen one quite like it.

  • ken

    Thanks for the information. It was well thought out. I am looking at designing a Diesel based RV which actually uses electric motors and batteries. This will come in handy

  • Rebecca Ingle

    Great video! Guess what, I understand it! That says a lot about how you present information and all your research and experience ? Looking forward to your next video .

  • Mark Hanlon

    When you were looking at converting to lithium, did you give any thought to using Tesla’s powerwall? At $7800 for 14kWh, it seems significantly cheaper than the 8D batteries, but would require more modification.

    • Curious Minion

      The Powerwall is great, but it is not rated for marine use, it must be mounted on a *stable* exterior wall for ventilation, and it’s really heavy.

      • swaan

        Powerwall 2 can be mounted on the wall or on the floor both indoor and outdoor but yes it is not intended for marine use (bye bye warranty). Considering it has 13.5kWh usable energy, is water cooled and includes an inverter – 276 lb / 125 kg is not THAT much.

  • Paulo Nehring

    Parabéns adoro seu canal.
    Tenho intensões futuras nesta vida, e suas informações tem me ajudado.
    Gostaria que vocês falassem sobre segurança, quando estão navegando, quando estão fundeados e quando saem do barco quem olha por ele.
    Paulo Nehring

  • Why do think you need all that power?
    Isn’t getting away about really getting away?
    I lived many years off the grid and did not need any electric to make passages. I found the most cost effective batteries were two golf cart batteries I bought used in the ABCs.

    • Curious Minion

      A lot of people certainly do live a lifestyle that uses a lot less power, but bringing you all these videos and blog posts means there are a ton of gizmos that need constant charging, as well as the kitchen appliances, the water heater, etc. Aboard Curiosity, more power is good!

  • Lynn Thomas

    Hi guys!

    I know it’s super pricey but have you guys considered converting your two diesel engines to fully electric? Check out We are moving from our rig to a Cat in 2018 and we just received a price from them to convert our two engines to electric. We’ll be fully off the grid with these things. We’re super excited! Yes, it’s a little pricey, but to us, it’s worth it! You can get an idea of cost by going to their website (yep, you’ll have to give your email address).

  • Eben Olivier

    Very informative, has been looking forward to this post for a while now. The one thing that might be worth mentioning also and probably most important is how to take care off them and make sure they last as long as expected. I am not sure how the LiFePO4 batteries has evolved over the last couple of years, but this( post gives a lot of detail about degrading batteries over time and because of keeping you batteries at full charge and in a too warm environment. I think it is also worth a read as any bit of information can go a long way for the upkeep of such an expensive battery

    • swaan

      Not mentioned in the article but I suspect the degradation problem is in 2 related parts, one of which you mentioned: too high temperature too high “float” voltage.

      1. Your battery pack has to be suitably sized for the loads you intend to use. High loads on small packs can create a lot of heat. All of the heat is also lost efficiency. Even when talking specifically about LiFePo4 – some batteries are intended for higher loads than others. (Don’t expect otherworldly performance from the cheapest battery.). Suitably sized li-ion banks hardly generate any heat (they have minimal losses).
      2. You need to factor in heat dissipation capabilities of the enclosure/cupboard of your battery. You can operate LiFePo4 in the hottest regions (much much better than SLA/AGM) but you need to be able to dissipate the extra heat from operation.
      3. As Eben Olivier mentioned, li-ion doesn’t like to sit at 100%. If someone says 80% DOD (depth of discharge) is best then it doesn’t have to be 100%->20%. This depends on how much power is available – if your battery is full most of the time then it might be wise to lower the max charge level and perhaps lower the max discharge level so you will end up getting 90%10%. These days even laptops do this (not all). If you get expensive li-ion cells then don’t scrimp on the controller!

  • Nancy Fernandez

    Great video guys! You go the extra mile printing out comparison charts and all. Thx, you two are so cute and yes funny 🙂

  • Mike

    Have you given any consideration to utilizing a windmill or water driven propeller to charge your batteries?

  • Carl & Grace Layton

    We converted our RV from 4 x 6v 200ah (400ah series parallel total) lead acid, to 4 x 12v 75ah (300ah parallel total) Relion Lifepo3 lithium batteries. Lead acid x 50% = 200ah usable. Lithium x 80% = 240ah. I’m still using the lead acid profile on the Xantrex modified sine wave inverter converter, which floats about 0.2 volts lower than the lithiums need to reach 100% charge. Modifications to the RV were sealing up and insulating the battery compartment, since these particular batteries won’t charge well below 32F. I added a 75 watt light fixture to the compartment for cold over night conditions. I plan to add solar and a full sine wave inverter. I haven’t boondocked yet since installation last summer, but will be heading west this summer where there are more/better boondocking opportunities. If you install Lithium, make sure all the interconnecting cables are exactly the same length so that the bank charges and discharges equally. We really like these batteries.

  • David Hall

    As I understand it you transferred your solar panels, inverter and other assorted equipment from the Bounder to Curiosity. Did you have to add any more panels and how did you get the right balance between energy gathering (solar panels) and energy storing (lithium batteries)?

    Thanks, very informative.

  • Claudio Cesar Bertoldi

    I’m following you about a year now and saw the LiFePO4 advantages from the begining, I even bought the Soda maker from your video “Living in the Wild” and many, many other things you bring to us, that’s why I’m very grateful. I’m trying to buy a 600 Ah Lithium batteries for my RV project since that time but dozens of stores in the US and even another countries said me they just can’t sell due to Air transport security restrictions. A maritime freight to Brazil would cost me several times the batteries cost. I would love to have any hint about this…

  • Michael

    Did you have to replace your existing battery charger and/or inverter to accommodate the lithium batteries?

  • Ken hollis

    Thanks,,,,my wife and I are just getting ready to install solar on our rv in the Mohave desert at mining camp,. Lithium is very expensive , But if two equals 4 and lasts 2 times as long, also our heat problem. They do seem right for me. Thanks

  • Roger B

    If I switch to Lithium-ion, can I still use my 3-stage charger in my RV or do I need to change to a different charging system?

    • swaan

      Only if the li-ion pack is intended as a drop-in replacement for lead acid. Those will also shut off completely if voltage drops too low.

  • Al

    Hi Guys, great video, and a couple comments/questions. I know that Tesla has Powerwall 2 for homes, and after looking at the Wiki on them (44 in × 29 in × 5.5 in (112 cm × 74 cm × 14 cm), 264.4 lb (119.9 kg), US$5,500, 13.5 kWh, 7 kW peak / 5 kW continuous, Cycles (during Warranty) 5000 (PW 1, PW 2 not stated), Operating temp. −4 to 122 °F (−20 to 50 °C)) I’d say that those would look Very appealing. Of course, they are designed around a (stationary) home installation, but if they could design if for the rigors of life on the open sea, that looks like it might be a home run.

    For my questions, will you be going into detail on how you determined that you only needed 4 dedicated house batteries right now? I know that writing that check had to be extremely painful, so that might have been the controlling factor. I’m still in the beginning stages of looking at joining this lifestyle, and the small amount of research I’ve done in this area so far seems to indicate that 24v is a more common voltages for systems, smaller wires being one advantage, potentially lower voltage drop as well I believe. You sort of indicated that you’d momentarily looked at a higher voltage setup, but you’d have to replace much of your system? Is cost the main reason you didn’t do the upgrade, or weren’t the advantages of the higher voltage system enough to sway your moving into that direction? Or both?

    How quickly in full sunlight (with minimal house draw, say you are anchored and away doing something ashore for the day) would your current solar setup charge your batteries, or don’t you know yet? Do you have more room or even a need for any more solar cells? Do you have or have you considered a wind generator to suppliment your power production? I’ve heard on other blogs/channels that there are good ones (reasonably quite) and not so good ones (horribly noisy, and because of such, either not regularly used, or even just removed). Thoughts on those?

    Have you gone through your system and isolated each draw, to document it’s max amp draw? That might be something you could consider, for diagnostic purposes down the road. Well, looking forward to you digging in even further in your next video, with more juicy technical details. There are those of us who (sadly) sort of geek out on these types of things. lol Thanks, hope Sailboat Tech vid #2 is coming out soon!

  • swaan

    Nikki and Jason did a good job but I feel like sharing some other important differences between SLA/AGM and Liion batteries:

    1. SLA/AGM likes to float at 100% charge level. If it stays (partially) discharged for a long time it will start crystallize and thus lose capacity. Liion (and its varieties generally) don’t like to stay the 100% charge level – They are left best somewhere between, even for years. No batteries (general use) like to sit empty. So to extend your SLA/AGM – keep the topped up. To extend you li-ions – avoid having them stay full or empty (a correctly set up battery management system takes care of that).
    2. The type of li-ion N&J use is LiFePo4 and they are arguably more safe than AGM. Even when pierced they won’t pose immediate danger even continue to provide power. That does not mean you should continue to use them after such an event.
    3. Li-ions work much better in extreme weather. SLA/AGM will age considerably faster in hot weather – 30C/86F means roughly half the life. Freezing temperatures wont directly kill either of them but SLA/AGM can be damaged when subjected to very low temperatures and high loads.
    4. Liion batteries age slower. Even after your rated 2000 or whatever cycles the useful capacity will not fall off the cliff but depending on chemistry, the degaradation can actually slow down when used as intended.

    • swaan

      Also keep in mind that N&J needed a drop in replacement for lead acid – if you are starting from scratch then this might not be the most economical route for you as you might be better off with a charge controller that is already intended for li-ion. Then you don’t need li-ion batteries (cells) with a management systems (BMS) of their own.

  • Thanks for the great summary. It certainly was more concise than the LeFePo4 thread on cruisers forum (5600+ posts and still growing 😉 I need to have my wife watch the video and try and talk her into the upgrade. Only trouble is, with our boat being brand new, it’s hard to justify the swap so soon.

    Anyway, for future videos, I’m looking forward to hearing your plans on upgrading your navigation equipment. As a big fan of B&G I hope they make your short list.

  • Mike

    I’m curious why you couldn’t take your Lithium battery bank from the RV and install it in the boat instead of buying an entirely new bank. Were they not compatible? Also, were you able to maybe exchange the old ones or sale them to help offset the cost of new batteries?

    Thanks for the great info you’re sharing!

    • swaan

      On their RV they had bare li-ion cells that had their own li-ion charge controller that ensures the safety of the battery pack. For the boat I assume they wanted to keep the existing system and simply swap the batteries. The voltages are different, the charging process is different – they aren’t not compatible.
      For the engines and generator you really have no other (sane) option. In an older blog post they discuss selling of the RV battery pack.

      • Mike

        Thanks, Swaan! Seems you have some experience with lithium batteries and the various forms and iterations of their installation. If you wouldn’t mind expanding on your answer for me, does this mean that for an install on an RV set up for SLA/AGM, I could either go the way they did (drop-in replacement for lead-acid no the boat with onboard BMS for each battery), or do a complete revamp where I use lithium batteries without onboard BMS and have a BMS unit outside the battery as they did on their RV? Sorry, but I’m geeking out here. I just hope my wallet can afford my enthusiasm.

        • swaan

          First of all different types of batteries have different operating voltage ranges. Nikki & Jason have li-ion batteries that have chargers and protection systems inbuilt so they are very tolerant about what you feed them – anything around 12V goes but looking at Relion datasheets it looks like they take measures so that your solar or RV charger (that tries to maintain a long service life of your SLA/AGM) doesn’t get freaked out about the “alien” li-ion system. The same system also protects the li-ion cells against any type of damage by cutting power – over-charging, over-discharging, over-temperature, short-circuit and over-loading. That definitely adds to the cost.

          A Li-ion (or programmable/multi-chemistry) solar/RV charger has the battery protection included so you can buy bare li-ion cells, arrange them in series (and parallel) and have the system monitor each one separately. (This means more wires.) There are many different li-ion chemistries. Charging parameters should always be confirmed in the li-ion datasheet.

          The latter is theoretically cheaper as you would have 1 charge controller per setup and not per battery (which includes: li-ion cells, charger & protection circuitry). The controller would give you a more detailed overview of the battery as well. Less overall circuitry also means less self-consumption (probably only important when storing). Another upside is serviceability – all the components could be replaced one by one. With the drop-in replacement you (repairman) will have a lot of guesswork after the warranty is out.

          In the end I feel money talks here – it could be that the old SLA/AGM solar charger/controller is junk anyway but maybe it is a powerful top end system with a remote display, dual or triple charging (solar, alternator, shore) and wastes very little power?

  • Carlin Comm

    That really brings it all into focus, showing the total cost, weight, and life cycles. Especially when you look at it long term over all life. Thanks for breaking that all down!

    Are you going to talk about the solar and charge controllers and inverters too? From an RV background, when you’re driving, you are basically automatically charging your battery bank from the alternator on the main engine, I assume if you’re running your engines you’d also be charging the bank on the sailboat, right?

  • swaan

    You guys are adorable, smart and funny too. Great to have you around.

  • Em

    Hey Nikki & Jason,

    Great job on the battery video!

    Here’s my question:

    What is the trendline in terms of battery pricing between lithium and agm?

    That is… Is the agm batteries going down in price faster than lithium!

    Because if space is Not a prob?
    And…If the agm batt is going down in price relative to time faster than lithium! Is lithium still tops in the long run?

    Cheaper to replace than empty out the bank acct for the initial hit?


  • Kim Betts

    Your total weight for the AGM is 624, but when the battery is spent and replaced, are you counting the weight of the now dead, replaced battery? Am I missing something?

  • Charlie

    Hi Nikki & Jason, I seem to remember you had a bunch of lithium batteries out of the R.V. Are you still using those or have they been replaced now. The long thin Yellow ones ?…

    PS – Best Wishes For A Safe Passage …:-)

  • debinvenice

    Can you mix batteries (different brands of li-ion or part li-ion and part agm)?

    • swaan

      Non-techincal answer: don’t do it.
      Technical answer: if you put the batteries in parallel you can do it provided their voltages have been equalized. Damage could occur otherwise as the battery with the higher voltage will forcefully charge the other ones until an equilibrium has been reached.
      Placing different brands or types of batteries in series is Not recommended due to differences in resistance – the cells that have the least of resistance get used the most. If you take that into account and match them (in terms of voltage and resistance) then yes you can. If they aren’t balanced in every way some batteries will end up discharged to death and others overcharged and and damaged too.

      Protip – sell your old ones and get all new ones. Best if all are the same make, model and production patch.

      • debinvenice

        Thanks Swaan!

        I’m a long way from needing or purchasing either type of battery but you have already saved me some future grief! 🙂

  • John Schretlen

    Very informatie video. I have two questions:

    Did your cat originally with with six batteries (1 eng, 1 gen, 4 main)?

    The four ‘house’ batteries look like there are housed in a custom waterproof set of boxes. Is that a Just Catamarans special installation?


Post a Comment