With fire being the worst disaster facing a boat I have been hesitant to consider switching to Lithium batteries. I understand that they have built in smart components to monitor and act against overheat or overcharges but my question is more on the practical and proven side of the issue. I understand most batteries come from China but that not all are manufactured to the same quality standards. Could I get a couple of Brand names that have a proven and safety record, but not necessarily being in the high price category and avoiding the cheapo market. I'm seeing the improvements in battery life and capacity that the lithium provide, but would like to start my research with a base of good and safe reliable batteries.
Lithium Batteries
- Thread starter Benny17441
- Start date
I bought my first lithium iron battery from Litime. 100 Ah 12.8 volt trolling motor version. Absolutely love it. Deep cycle battery expired in the RV. We bought another Litime 50Ah for it. It’s been amazing. So small and powerful we take it on our sailboat.
I have been flying R/C for 25 years. We use lithium ion and lithium polymer. Those are the battery types that we have developed our concern from. I have had no issues and always feel safe around the lithium iron. The best part, if you have to pack it around, they’re so light. A+
I have been flying R/C for 25 years. We use lithium ion and lithium polymer. Those are the battery types that we have developed our concern from. I have had no issues and always feel safe around the lithium iron. The best part, if you have to pack it around, they’re so light. A+
Rod (aka Mainesail) has an article on this question…
This article may be a bit out of date, as I believe Rod is now “promoting” WattCycle batteries (or at least some specific ones).
Other name brand ones include Battleborn, LiTime, and many others.
I went the discount route, and replaced 2 older 6-volt GC batteries in series with 2) HumsiENK 100Ah Smart batteries. The LFP batteries were about $10 more each than replacement GC batteries at Sam's Club. I wanted to try the technology so gave these a try.
I did buy a new Victron charger to maintain the LFP batteries. I kept my lead acid battery as a starter battery, and rewired things so the starter circuit and house circuit are totally separate. Each has its own charger and cut off switch.
My batteries are “smart” batteries that I can keep track of with an app. Maybe a curse because I get a bit anal about voltage differences, etc.
My only issue ( and I am not sure how big of a deal it is), is that sometimes the 2 batteries (wired in parallel), get “unbalanced”…one has a higher voltage or higher SOC than the partner battery. Or one seems to be servicing the house load and the other one is not putting out any juice. Would it correct itself after a while? I assume so, but it bugs me. I fix it by recharging each battery separately at 14.6 volts until it is at 100% SOC, then the other one and then put them back in parallel.
I recently saw this video discussing the issue with WattCycle batteries...maybe all “smart” batteries?
I think the safety features have improved tremendously, and I am pretty comfortable with my LFP battery bank.
But you can pay 3x or 4x for Battleborn if it makes you feel better.
Greg
Our Recommended Drop-In LifePo4 Batteries - Marine How To
Rod, What are your Recommended Drop-In Batteries for Marine Use? Disclaimer: I still type with one finger as my left arm is still 100% paralyzed. Typo's happen and I try to edit them when I see them or readers point them out.
marinehowto.com
This article may be a bit out of date, as I believe Rod is now “promoting” WattCycle batteries (or at least some specific ones).
Other name brand ones include Battleborn, LiTime, and many others.
I went the discount route, and replaced 2 older 6-volt GC batteries in series with 2) HumsiENK 100Ah Smart batteries. The LFP batteries were about $10 more each than replacement GC batteries at Sam's Club. I wanted to try the technology so gave these a try.
I did buy a new Victron charger to maintain the LFP batteries. I kept my lead acid battery as a starter battery, and rewired things so the starter circuit and house circuit are totally separate. Each has its own charger and cut off switch.
My batteries are “smart” batteries that I can keep track of with an app. Maybe a curse because I get a bit anal about voltage differences, etc.
My only issue ( and I am not sure how big of a deal it is), is that sometimes the 2 batteries (wired in parallel), get “unbalanced”…one has a higher voltage or higher SOC than the partner battery. Or one seems to be servicing the house load and the other one is not putting out any juice. Would it correct itself after a while? I assume so, but it bugs me. I fix it by recharging each battery separately at 14.6 volts until it is at 100% SOC, then the other one and then put them back in parallel.
I recently saw this video discussing the issue with WattCycle batteries...maybe all “smart” batteries?
I think the safety features have improved tremendously, and I am pretty comfortable with my LFP battery bank.
But you can pay 3x or 4x for Battleborn if it makes you feel better.
Greg
You can’t go wrong with batteries from Victron, Relion, or Mastervolt. Yes they’re “premium” but the price difference might be worth the peace of mind, and maybe isn’t that great. The charging system and controls also need to be chosen and configured carefully. This is a deep subject, but I’m not an expert.
The system on my boat is a mix of Victron and Relion.
The system on my boat is a mix of Victron and Relion.
When we talk about “lithium batteries,” it’s really important to remember that the term is so broad it almost loses meaning.
Within the rechargeable family (lithium-ion), there are several very different chemistries: LiCoO2, NMC, NCA, LiFePO4, and others. Each has distinct characteristics in terms of energy density, cycle life, and - critically - thermal stability.
That’s why general statements like “lithium is dangerous” or “lithium is safe” don’t really hold up. A LiFePO4 bank on a boat behaves very differently from a high-energy cobalt-based pouch cell in a laptop or drone. Most of the earned reputation of lithium batteries being fire hazards comes from experiences with LCO or NMC batteries. Thankfully, these days, when people talk about lithium marine batteries, they are talking about LiFePO4 which has generally better performance characteristics for the application but, critically, virtually none of the safety risks of LCO or NMC.
So, any meaningful discussion of safety has to start by naming the chemistry. Without that, we’re lumping together things that shouldn’t be compared.
Within the rechargeable family (lithium-ion), there are several very different chemistries: LiCoO2, NMC, NCA, LiFePO4, and others. Each has distinct characteristics in terms of energy density, cycle life, and - critically - thermal stability.
That’s why general statements like “lithium is dangerous” or “lithium is safe” don’t really hold up. A LiFePO4 bank on a boat behaves very differently from a high-energy cobalt-based pouch cell in a laptop or drone. Most of the earned reputation of lithium batteries being fire hazards comes from experiences with LCO or NMC batteries. Thankfully, these days, when people talk about lithium marine batteries, they are talking about LiFePO4 which has generally better performance characteristics for the application but, critically, virtually none of the safety risks of LCO or NMC.
So, any meaningful discussion of safety has to start by naming the chemistry. Without that, we’re lumping together things that shouldn’t be compared.
This is definitely not typical. It seems to be a part of the BMS “Full charge protection“ that has been showing up in more batteries. Epoch has “Full charge protection“ on some of its‘ batteries, but it doesn‘t affect the ability to discharge… which is what is going on here. I would try to charge to a lower voltage and see if you can prevent the BMS from disabling the discharge FETs. Start at 13.8V with about 1 hour of absorption, then see if both batteries will discharge together. If that works, try it again, increasing the voltage by 0.1V. I wouldn’t go higher than 14.4V. Charging to 14.6V can cause some issues if you have slight imbalances in the cells. I used this technique on my Epoch 48V battery to keep it from engaging Full Charge Protection and causing a voltage spike.
Epoch batteries. You can order them here:
At the end of the day all the cells are coming from a couple of companies in China, even when you buy from a “premium” brand. The main difference is in cell “grade” and BMS quality.
My general rule is to buy from companies who have a vested interest in preserving their brand reputation and/or who can be held legally accountable, as they have incentives not to sell unsafe garbage.
LiTime is active about ABYC certification and ABYC standards in general, which gives me a measure of confidence in their products.
My general rule is to buy from companies who have a vested interest in preserving their brand reputation and/or who can be held legally accountable, as they have incentives not to sell unsafe garbage.
LiTime is active about ABYC certification and ABYC standards in general, which gives me a measure of confidence in their products.
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Also cell matching, which is extremely important. Some cheaper brands don’t match very well and then you could end up with a large imbalance in cell SOC, causing reduced capacity and even rendering the battery useless if the imbalance gets too large. I have several LiTime small batteries (6Ah and 12Ah) and one of the 6Ah is so imbalanced it goes into HVC at around 13.8V. Still, it works and is much better than the lead acid version, so I am happy with it… But with the larger batteries I wouldn’t buy one without Bluetooth monitoring, so at least you can see the problem and hopefully get a warranty exchange.
The manufacturer gave me the 14.6 volts at 5 amps charge plan to equalize these batteries. The BMS usually turns off the charging circuit at some point. I did them this week, and put them back in the boat. Seemed “in sync“ yesterday after my sail and today when I checked them. Voltage was exactly the same.
Greg
Mid to high quality marine lifepo4 batteries can be procured from Victron, BattleBorn, SOK and Epoch. SOK have a built-in fire extinguisher. SOK and Epoch have CAN-BUS (Victron) communication to regulate the charge voltage and current, which avoids inadvertent BMS disconnects (if you have a Victron ecosystem onboard).
Before making the swich, it might be a good idea to have a marine electrician review your current dc electrical architecture and advise on required modifications. Will you wire the alternator to the house or starter batt? Starter is easy, but you won't get much benefit from Lithium unless you hook it up to the Alternator. Then you may need an external alternator regulator, larger wiring, Class T fuses, etc....
Unlike Lead Acid / AGM, you can't just parallel multiple Lifepo4 batteries in parallel just based on voltage .... they have to have the same state of charge. Bottom line is there's a large learning curve.
It's not a drop-in change, it requires a complete review of the DC electrical system and likely extensive modifications.
I'd suggest a Lifepo4 with a built-in heater if you are in norther climates (Mayne, Washington state)... not required for Florida. Better brands offer IP67 sealed batteries. Some offer Victron comms to manage your full charging system (alternator, solar, inverter/charger). You'll likely need one or more DC-DC charger. Do you wan to be able to start the engine from the House Bank? Then the specs of the BMS have to be looked at very carefully, as many BMS will disconnect when trying to do this.
Given that fire is the single greatest risk aboard a boat, I would not go with budget batteries. Many brands have been tested and it was demonstrated that their BMS often don't perform as advertised and may lack essential safety protections. There is very little difference, in terms of safety between a quality and cheap Deep Cycle flooded batteries. It is not the case for lithium... you get what you pay for.
To update my 2001 sailboat to lithium, the cost of the modifications, rewiring, fuses, alternator regulator, lithium friendly charger, DC-DC charger, etc... was about the same cost as the batteries ($3000 CAD for batteries, about $3000 CAD for all the rest).
Here's a good place to start to learn more:
ABYC E-11 and E-13 standards
www.pysystems.com
Before making the swich, it might be a good idea to have a marine electrician review your current dc electrical architecture and advise on required modifications. Will you wire the alternator to the house or starter batt? Starter is easy, but you won't get much benefit from Lithium unless you hook it up to the Alternator. Then you may need an external alternator regulator, larger wiring, Class T fuses, etc....
Unlike Lead Acid / AGM, you can't just parallel multiple Lifepo4 batteries in parallel just based on voltage .... they have to have the same state of charge. Bottom line is there's a large learning curve.
It's not a drop-in change, it requires a complete review of the DC electrical system and likely extensive modifications.
I'd suggest a Lifepo4 with a built-in heater if you are in norther climates (Mayne, Washington state)... not required for Florida. Better brands offer IP67 sealed batteries. Some offer Victron comms to manage your full charging system (alternator, solar, inverter/charger). You'll likely need one or more DC-DC charger. Do you wan to be able to start the engine from the House Bank? Then the specs of the BMS have to be looked at very carefully, as many BMS will disconnect when trying to do this.
Given that fire is the single greatest risk aboard a boat, I would not go with budget batteries. Many brands have been tested and it was demonstrated that their BMS often don't perform as advertised and may lack essential safety protections. There is very little difference, in terms of safety between a quality and cheap Deep Cycle flooded batteries. It is not the case for lithium... you get what you pay for.
To update my 2001 sailboat to lithium, the cost of the modifications, rewiring, fuses, alternator regulator, lithium friendly charger, DC-DC charger, etc... was about the same cost as the batteries ($3000 CAD for batteries, about $3000 CAD for all the rest).
Here's a good place to start to learn more:
ABYC E-11 and E-13 standards
Video | Pacific Yacht Systems
Pacific Yacht Systems can design and install exactly what you need, so that you feel safe and enjoy your boat to its full potential. We offer design, installation, service, and support for marine electronics and electrical services.
A few considerations... sounds like you have some significant issues that could result in equipment damage and/or total loss of DC power...
Were the batteries matched in terms of state of charge or voltage when they were wired in parallel?
Are they quality batteries with matched cells?
Did you cycle each battery 2-3 times before wiring them in parallel?
14.6V is pretty high.... but depends on the actual cells inside the battery. 13.8V might give you 98% capacity, do you need that last 2% or prefer risking cells going over 3.65V and becoming permanently damaged? (14.6V / 3.65 V per cell ... which is the MAX for most lifepo4 cells....) 3.45 to 3.5 V / cell is a much gentler charge regime for Lifepo4 Cells. 3.45 x 4 = 13.8 V.
Sounds like you have some random BMS disconnects, possibly due to high cell voltages.
Does your battery have a remote (Bluetooth) monitor?
Sounds like those batteries would not do well on a boat and there's risk of damage to your alternator if they randomly disconnect....
What is your charge current? What is your absorption time?
That article is very misleading. I still see it being referred to, but it should be deleted from the memory of the internet as it is doing a disservice to many boaters that don't know any better.Rod (aka Mainesail) has an article on this question…
Our Recommended Drop-In LifePo4 Batteries - Marine How To
Rod, What are your Recommended Drop-In Batteries for Marine Use? Disclaimer: I still type with one finger as my left arm is still 100% paralyzed. Typo's happen and I try to edit them when I see them or readers point them out.marinehowto.com
This article may be a bit out of date, as I believe Rod is now “promoting” WattCycle batteries (or at least some specific ones).
There is a small sentence in the article "drop-ins are not suitable for every boat " which gets missed by most... in reality, drop-ins are not suitable for MOST boats. Don't trust me .. research what Nigel Calder has to say and what the ABYC E-13 standards include....
We have a local marine electrician who's main source of income is spending a week on boats fixing everything, after the owner tried to do lithium on their own and things didn't quite work out ... (BMS disconnects, slow charging, no DC power at times, blown alternator diodes, etc....)
That's too high a voltage and too high amperage to balance, they have no idea what they are doing, is this a budget battery?? If you value your life and your boat, ditch them on Marketplace and get some mid range cells like SOK.
The battery balancer likely can only do 0.1 Amps.... Research how to balance Lithium packs. You'll need an adjustable voltage/current power supply and lots of patience. If the cells are not matched, they will constantly drift out of balance.
On a boat, you should NEVER see a BMS disconnect. If you do, something is not right in your installation.
I suggest that you spend some time reviewing DIY Solar Power with Will Prowse You'll find a lot of good relatable info from his channel
This indicates they don’t understand what is going on. They are giving advice on balancing two batteries at different SOCs, but not addressing why they are at different SOCs. Apparently they are unaware of how their BMS protection can prevent a battery from discharging after charging when it is in parallel.
You should not let the BMS stop the charging this way. It may be a “Full Charge” protection, which is not as bad, but at 14.6V it is more likely a cell over voltage (HVC) event. This is a safety feature of the BMS and shouldn’t be a normal event. It would be like pulling into the garage and letting the front bumper stop the car when it hits the back wall.
This BMS disconnect will cause a voltage spike that could damage some electronics on your boat. Also, it could be the reason one battery won’t come out of protection mode and discharge after charging to 14.6V in parallel. Really you should lower the charging voltage to 14.2V and see if that prevents the BMS disconnects.
Also, when you charged them at home and then brought them to the boat that is different than charging them on the boat and then immediately discharging them. You don’t want to have to disconnect them everytime you charge them.
THIS is the key! Back when I built my own EV there were a lot of guys (myself included) building packs out of ThunderSky and CALB cells. There were a couple of fires, but they came from poorly designed and/or poorly installed BMSes. Likewise, a majority of cell imbalances were caused by the quiescent currents in the BMS. Several members even came to the conclusion that they'd be better off without one. They ignored the inevitable voltage mismatch that will come from the cells' inherent self-discharge rates and the primary cause of lithium fires generally, which is over-charging, but they had a point. Even in my professional career, as an EE, I have witnessed poor BMS design - by a company that designs and builds OEM packs, no less - cause a fire. I've also seen enough circuit boards "let the smoke out" to be uneasy with the idea of having one taped to the side of a lithium battery, especially a high power circuit like a BMS protection switch subjected to extreme electrical stress like an emergency disconnect. I would never run without a BMS, but I'd be just as nervous with a low quality one.
I prefer to charge LFP to 3.475-3.5V/cell, but it's probably overkill: cycle life at 3.6V is still better than you're likely to need in most sailboats. Note also that, depending on the design of the BMS, deliberate under-charging may prevent proper balancing. As for the risks of 3.65V, my understanding is that LFP has the same 4.2V absolute maximum as other chemistries, but that going above ~3.6V adds no capacity while also significantly degrading cycle life. The wide 0.6V margin between full charge and over-charge (compared to about 0.05V to 0.1V for traditional Li) is a major component of why LFP is safer. Note that charging to 4.2V significantly degrades the life of traditional cobalt cells too, but that's another topic...
Benny, I went Lithium about 5 years ago and I find it quite frustrating that so many so-called DIY experts and even some actual professionals make a big deal, over complicate things and tell you all sorts of things that must and must not be done. Many here will absolutely disagree they will make all sorts of statements about misleading people etc, so I am out all most on my own here. I tell you this in essence to be clear to you. When I went (lifpo4) and I agree with someone above, you shouldn't confuse lithium and Lifpo4, i went with the view that my install would be a test or experiment to see what was correct about all the experts. So I did things that most said would go bang or my boat would catch fire or they wouldn't last etc etc. So I retained AGM start battery, i didnt use any DCDC chargers, I didn replace regulators or charge controllers, didn't change settings. A long the way I learnt some of the myths and why some of the statements that were true and others weren't. So I will ignore the flakt that comes back unless you have genuine questions. Buy only Lifepo4 batteries, mine were relatively cheap Chinese brand, that were often used in cars, supposedly fire resistant etc, I bought individuals cells, simply because 9 out 10 conventional batteries (ie Gell agm, standard) when those batteries fail it usually one cell dies and the whole battery is useless. Buy buying individual cells the thinking was if one dies i can replace just one cell and as this was an experiment what does it matter. Every one here will tell you can't do it because of balancing etc Keep in mind every conventional battery (ie non Lithium) will have the same misbalance potential as Lithium, its just we never knew or monitored it as we do to day with a BMS. Some of the very old wet cell batteries you could actually get your meter on the cells, or if you had say multiple agms or gels, in parallel they almost never aligned if you split them apart and measure each battery. I actually put my BMS across my AGMS as part of my project. LifePo4 is no different, yep in the ideal world you want it balanced and the closer the better. Then came all the charger changes etc, be it solar controllers' alternators start batteries etc. Bottom line to all of that (and I changed nothing by the way) is none of that needs to change provided it was at least 3 stage charging systems working correctly and within spec of your original batteries and you at least have a BMS. Like any battery technology you may not get the best it can be out of it, but you will not damage it or shorten their life, if your existing charging systems was working correctly. The biggest risk in this area is boats that are mains powered 24x7 for 9 months of the year, only get used at xmas and have high float settings. The last point I will make is that most even here will agree with is that Lifepo4 can deliver more current for a much longer time than many if not all other conventional batteries. This good for us, but also bad for us if there is a problem. Unlike a conventional battery that will die quickly with a short, Lifepo4 wont. So consider say 200amps of AGM. The chances are that if that install was done correctly that the cabling from the battery would deal with a very heavy load or short for the time it takes while the battery would slowly die assuming its fuse didn't blow. With LifePo4 it will supply many more amps to that short continuously and for longer, then just stop ( assuming the BMS hasn't shut down as it should) There is your fire risk, not the LifePo4, but what is capable off. My suggestion if you have some technical skills buy single cells start small, make sure you have a BMS and a decent fuse. If you have say 100amps now of AGM or Gell, get 100 amps of LifePo4. That will at least double your useable power. If you have no Technical skills buy a name branded complete LifePo4, drop in, make sure it has a BMS you can monitor, again have decent quality fuse and don't worry about all the rest. Its not that complicated.
Like you say "The best solution is usually the simplest that meets your specific needs."
Like you say "The best solution is usually the simplest that meets your specific needs."
It really is not as complicated as some would make it out to be. Sure, there are a few things you need to be aware of, but in most cases, the conversion is very simple.
The problem is that most people who are talking/writing about marine lithium tend to not well-intentioned and sincere, but honestly, not very well-informed. On Marcham's suggestion, I sought out what Nigel Calder had to say on the subject. Honestly, he is hit-and-miss on the topic. I find he makes a lot of statements that do not apply to all chemistries.
But, that led me to run across this fellow who gives 24 minutes of good information ... which is rare on this topic:
The problem is that most people who are talking/writing about marine lithium tend to not well-intentioned and sincere, but honestly, not very well-informed. On Marcham's suggestion, I sought out what Nigel Calder had to say on the subject. Honestly, he is hit-and-miss on the topic. I find he makes a lot of statements that do not apply to all chemistries.
But, that led me to run across this fellow who gives 24 minutes of good information ... which is rare on this topic:
