Boat Batteries – Help me Make a Final Decision

[Tomthumb62]

I think I read on one of the forum or video comments you could install the JBD app to see cell voltages on Aolithium. Don’t know how reliable that is though.

That would be nice if these lithium BMS's could be read by any bluetooth app out there...I think we could see some really great apps then.

Looking more at the Aolithium - that does look like a nice battery. Tempting. But it would require me to upgrade my system to using bus bars (another $60+ cost), which while I would love to do, it's not necessary if I stick to a single battery rather than 2x100Ah in parallel.

While a battery with an openable top would give better peace of mind knowing I could replace the BMS if needed, I think if I get 5 years out of a cheap(er) lithium like the Powerurus, that would be great. Will Prowse has been saying that if you win the quality-control lottery of all these cheap $300 batteries, your battery is likely going to last you a very long time if you take care of it. If this wasn't a limited-use leisure rig, I'd probably just go with SOK for both replaceable cells and BMS, but it doesn't make sense to spend that kind of money on a leisure rig.

 

[Sam Cho TX]

These were on my radar but they were OOS for a long while. Pricing per Ah is in the same neighborhood as EG4, PowerUrus, and Aolithium. Paying for assembly puts them in SOK and KiloVault territory. The value proposition starts to get interesting when you use cells from 18650batterystore. Brings the cost down almost to budget battery levels.

haha smart minds think a like I was going to do the same thing get some 304 grade B and kits from SFK... then I tested them:

EVE 304 Cells from 18650batterystore & zke-40 testing.

Notice the end of discharge voltage decay drop off on cell 303. It is quite different of the other cells and is indicative of a cell that has not had enough initial cycles where the cathode and anode capacity curves have not reached their final alignment. It may gain in AH's after a few...

diysolarforum.com

Trash.

Maybe the 280K, but from what my experience is that that is a marginal cell and is 276-278 AH on a tester and about 270 AH in a battery pack vs the 304 which are 310 on average while in a pack with a BMS so 40AH difference in the real world.

 

[markpj23]

A better than average chance that if you do not use a UL listed battery, your insurance would not cover your claim should something happen. The new ABYC standard also requires an audible alert from the BMS prior to reaching low voltage cutoff, etc. FWIW if this is a concern for you.

 

[4arch]

A better than average chance that if you do not use a UL listed battery, your insurance would not cover your claim should something happen. The new ABYC standard also requires an audible alert from the BMS prior to reaching low voltage cutoff, etc. FWIW if this is a concern for you.

Best I could ever figure on this issue is it became a big scare a couple of years ago on a few boating forums but insurance denials for LFP never were a very widespread thing, except among a handful of mostly non-US insurers. Not trying to be dismissive and I do agree UL listed probably doesn't hurt.

 

[Marinepower]

In my 40 foot sail boat, I decided to go with this system: https://freynewenergy.com/modules/

Good, strong 3/8th copper terminals and a ready made system to secure it to the boat.

Requires an external BMS, but that allows more options for high load applications (windlass) and allows me to have a screen that I can monitor all the cells at a glance.

 

[audiobill5]

Have you considered old school AGM batteries

GENEREX - Energy & Facility Management Solutions

GENEREX is the world-leader in the area of UPS networks and one of the few manufacturers with a production depth of over 90%, with software and devices being assembled in Germany. Along with these products GENEREX offers extensive technical support and consultation for OEM partners and consumers.

www.generex.de

I've always been concerned about the fire risk involved with lithium

lithium ion NOT lithium iron are a fire problem! out with the old in with the new.

 

[markpj23]

Best I could ever figure on this issue is it became a big scare a couple of years ago on a few boating forums but insurance denials for LFP never were a very widespread thing, except among a handful of mostly non-US insurers. Not trying to be dismissive and I do agree UL listed probably doesn't hurt.

Agreed - the difference now, however, is that the new ABYC standard has been published.

 

[4arch]

So as an update, I’ve eliminated what were options 1 (Aolithium 100Ah) and 3 (DIY) in my OP. Still standing are options 2 (EG4 LifePower4 400Ah) and 4 (cheap Amazon battery but instead of multiple 100Ah as I originally proposed I’d go with larger capacities).

This thread has been helpful in that I’ve been convinced 1 or 2 larger capacity batteries make more sense than 3 or 4 100Ah wired up in parallel.

My thinking is evolving on low temp protection in that it seems occasional charging below freezing at rates below .1C is not likely to result in notable capacity loss. The likelihood that my batteries would receive any charge at all on days 32F or below let alone above .1C is so infinitesimally small I’m just not that concerned about it.

Still debating if I do go the cheap Amazon battery route which one to buy or if I just bite the bullet for the EG4.

 

[Odom1957]

I have done a few installs with LITime (Ampere Time) batteries, and even more with Life Blue batteries with zero issues, but on all our trolling motor installs on boats, we use Abyss batteries exclusively.

I am currently doing a 30kwh system with 4 5k quattros on a 65' Donzi, and using LI Time batteries.

The need for low temp charging cutoff is pretty rare in offgrid type installs, as the batteries would never reach freezing temps in the location they are installed, which is one of the reasons why we use Abyss batteries for trolling motor installs, as they could reach freezing temps regularly, and are normally located somewhere where they could get wet, like an anchor rode locker or forward storage compartment on center console boats.

As others have said though, a simple external temp sensor would solve that problem and eliminate the need for the protection inside the battery.

Personally, in a sailboat, I would use a Life Blue or LI Time battery, as they seem to be the most cost effective in our experience.

Just remember that you'll need either a special alternator/external regulator, or a Lead battery in the system to keep from ruining the alternator when the lithium disconnects itself due to some fault, like over volt, under volt, excessive current draw, etc. We use an AGM for starting engines/generators, and DC-DC to charge the lithium in all our installs, unless the boat has a special alternator.

 

[JoeHam]

We use an AGM for starting engines/generators, and DC-DC to charge the lithium in all our installs, unless the boat has a special alternator.

So if I understand correctly the LiFePO4 batteries are connected to the starter batteries via the DC-DC charger only.

No connection to the alternator.

Then a common negative connection with the starter battery and the positive connection via DC-DC charger like a Victron Orion or similar device ?

 

[Tomthumb62]

Did you end up deciding yet?

We went with the Powerurus. Was leaning that way anyways but then Will now lists it has his "best value" battery pushed us a bit more. Which looks like perfect for our needs. $730 with coupon, no tax, free shipping, free charger. Since you need 400ah, the budget model eg4 looks better, though.

 

[Nobodybusiness]

Sun Fun Kits 304AH is nice and easy build, $1256 makes it the cheapest option while still having quality components and genuine cells: https://www.sunfunkits.com/product/54/sfk-v4-premium-heated-w200amp-bms-wbluetooth-ready-to-build

Their is also the prebuilt but its $250 more: https://www.sunfunkits.com/product/...f-heating-136v-lithium-iron-phosphate-battery.

I have 3 sfk kits, very pleased with the performance/price ratio.

Whole thread on here about Sun Fun Kits.

A lot of folks in here might disagree with you unless things have changed significantly since that thread.

 

[Nobodybusiness]

Look for batteries that are fully field serviceable, such as SOK (could be others these days):
- case opens, bolted conns vs welded, etc.

If one "battery" fails, not only is it fixable in the field, but you can overhaul it in various ways:
- replace the bms with your choice, to gain more features, etc
- one cell dead, the others are still good ... carry one space cell, field fix a "dead" or problematic battery

Sooner or later, everything fails or gives grief ... how it fails, and how field-fixable, and the support from the vendor to get there, is also important. Perhaps more so on a boat, depending on excursion lengths & such. Basically, a spares program, and a field-serviceable program ...

I replaced wiring harness in one of my SOKs because of a bad Temp sensor.

Very serviceable batteries.

 

[Supervstech]

lithium ion NOT lithium iron are a fire problem! out with the old in with the new.

F.Y.I. all batteries with lithium in them are Lithium Ion…

LFP is a lithium ion battery, but it does not have an exothermic reaction to overcharge, or failure like LiNMC cells or LIpolemer cells…

 

[4arch]

Did you end up deciding yet?

We went with the Powerurus. Was leaning that way anyways but then Will now lists it has his "best value" battery pushed us a bit more. Which looks like perfect for our needs. $730 with coupon, no tax, free shipping, free charger. Since you need 400ah, the budget model eg4 looks better, though.

Congrats on your choice, I’m sure it will work out great! I went with 2x LiTime 200Ah. Got two for $1071 out the door. For some reason they’re $95 cheaper from eBay than Amazon even though they’re the same battery from the same seller. While I won’t have Bluetooth, I have an existing Victron monitor I can reuse for state of charge. I figure I can capacity test these once a year to verify performance.

The Powerurus would have been almost $400 more for me and the EG4 even on sale $500 more. And since people keep talking about SOK, I could have gotten four LiTime 200Ah for the out the door price of two 206Ah SOK. Just couldn’t justify those prices based on my use case.

 

[Sam Cho TX]

Whole thread on here about Sun Fun Kits.

A lot of folks in here might disagree with you unless things have changed significantly since that thread.

Link?

 

[TimE]

It's so easy to build your own. I did that. 8x280Ah CATL cells. JK bms, class T fuse, Victron Smart shunt. Victron B2B and MPPT. I purchased a spare BMS as they are so cheap. Couldn't be happier with the set up. I still carry lead as back up, for now

 

[Tomthumb62]

Congrats on your choice, I’m sure it will work out great! I went with 2x LiTime 200Ah. Got two for $1071 out the door. For some reason they’re $95 cheaper from eBay than Amazon even though they’re the same battery from the same seller. While I won’t have Bluetooth, I have an existing Victron monitor I can reuse for state of charge. I figure I can capacity test these once a year to verify performance.

The Powerurus would have been almost $400 more for me and the EG4 even on sale $500 more. And since people keep talking about SOK, I could have gotten four LiTime 200Ah for the out the door price of two 206Ah SOK. Just couldn’t justify those prices based on my use case.

Sounds like a good deal. I did find some open box SOK 206Ah, but still with tax and shipping, it was $900.

I’m guessing you’re in a warm enough marine environment to not need to worry about low temp cutoff protection? I know you can add it externally with Victron gear, but at added expense and wiring complexity. I would have considered LiTime if I didn’t need low temp protection in our three season camp trailer.

Main thing I wanted Bluetooth for is to view the voltage of the individual cells, you can’t do that with a shunt. Seems to be perhaps the best way to tell if a cell is faulty, which could lead to a warranty claim, but I’m doubting I’ll ever need to do that.

 

[jberger]

You will really appreciate cell level monitoring when you have issues beyond just overall battery voltage.
The shunt options are great for tracking the status of the bank, and triggering actions like disabling charging when the temperature is too low, activating a charger when the voltage is low, etc.
The cell level monitoring is ideal when you are trying to understand the state of health, cell imbalances, IR, etc.
Ideally, you would have access to both, even if you don't use them all the time.

 

[4arch]

I’m guessing you’re in a warm enough marine environment to not need to worry about low temp cutoff protection? I know you can add it externally with Victron gear, but at added expense and wiring complexity. I would have considered LiTime if I didn’t need low temp protection in our three season camp trailer.

It does get below freezing here but I would rarely if ever be in a position of the batteries receiving charge current in freezing conditions as the boat will be winterized and usually on land and unplugged. Also, the more you dig into the issue it seems charging at <0.05C in temperatures down to about 10 deg F is unlikely to have any negative effects, especially if it only happens occasionally. If there were ever a reason I didn't want to disconnect my charger when it was likely to go below freezing, I could turn it down to 10 or 15A max charge current to stay under 0.05C. These factors just make low temp charge protection seem unnecessary in my use case, though I still wish more manufacturers would include it by default.