Lithium drop ins?

[Sailshabby]

In olden tymes (like a whopping couple of years ago), it was cheaper to order Lithium cells from China and build one’s house bank from scratch. My impression these days is industry might have caught up with reliable and financially comparable drop in batteries, but I don’t have a ton of data points to back that assumption up. I plan on switching from my 440aH LifeLine AGM house bank in the near future and would appreciate any feedback, including what you might have purchased (or avoided. TIA!)

[Avionics_Joe]

I bought 16 cells from:
CALB USA Inc.
5565 Daniels St., Chino, CA91710
Tel: +1 909-591-8881, Fax: +1 909-865-8881
This was in 2020, love them. If you have all programable charge sources you don't need a BMS.

[CharlieJ]

#2

If you have all programable charge sources you don't need a BMS.

IMHO, operating a LFP bank without a BMS is like driving without a seat belt, going out in a boat without a PFD, working on a construction site without a helmet. Like this safety equipment, the BMS is there primarily to protect the bank should all of the microprocessors on charging source and control over load discharges fails. A sophisticated BMS does other functions, but its main function is to provide ATC and ATD signals when all of the conditions are met.

If you want to insure your vessel, you will need a BMS.

[Cari Laut]

Sure you could run lithium without BMS, but it’s not wise as far as I’m concerned. A thermal runaway is nothing to take lightly. If there was something to add another safety feature, I’d add it. Rather spend more money than risk losing the boat.

[Avionics_Joe]

I do have alarms if anything goes haywire but in 4 years it's worked perfectly.

Mark explains this system far better than I can: https://svreach.com/boat-blog/li-batteries.html

[wholybee]

Originally Posted by Avionics_Joe

I bought 16 cells from:
CALB USA Inc.
5565 Daniels St., Chino, CA91710
Tel: +1 909-591-8881, Fax: +1 909-865-8881
This was in 2020, love them. If you have all programable charge sources you don't need a BMS.

Strictly speaking, you don't need a BMS. But it is a very negligent install, and the sort of DIY crap that causes insurance companies to require lithium to be installed be professionals. All to save about $100 on a battery bank that in 2020 probably cost you thousands. Idiocy.

You do need a balancer of some kind, and the easiest way for that is to get a BMS. Quality cells will stay balanced for a long time without one, but eventually even quality cells will go out of balance.

I have a bank made from Calb cells also built in 2020. I have never had an HVC event. However, I did *one* time have a LVC event when I had to leave the boat for 2 weeks, and with 2 weeks of rain the solar couldn't keep up. If I followed your design with no BMS, my very expensive battery would have been ruined.

So in reality, you really do need a BMS, even if you manage years without a disconnect, and have all your charge sources programmed correctly.

[hjohnson]

Originally Posted by wholybee

I have a bank made from Calb cells also built in 2020. I have never had an HVC event. However, I did *one* time have a LVC event when I had to leave the boat for 2 weeks, and with 2 weeks of rain the solar couldn't keep up. If I followed your design with no BMS, my very expensive battery would have been ruined.

I'm similar in that during the cold snap we had back in January, we had a low temperature event. The BMS detected that the battery was at 2C (I was conservative in my settings) and not only did I get an email alerting me of this fact (Thanks Victron VRM!), it immediately set the current limit on the batteries to 0A, and stopped both my solar and inverter/charger from trying to charge the battery when this shouldn't be done. The battery eventually got down to -2C before I was able to get aboard and open up the compartment and turn on the electric heater.

Had I not had the BMS and the monitoring, we likely would have destroyed the battery.

I also had a semi-accidental HVC event, where I absentmindedly shut down the BMS while the engine/alternator was running. Fortunately this worked perfectly because the BMS sent an alarm signal to my Wakespeed, which in turn killed the alternator field before anything on the DC bus got fried.

[GILow]

Originally Posted by Sailshabby

In olden tymes (like a whopping couple of years ago), it was cheaper to order Lithium cells from China and build one’s house bank from scratch. My impression these days is industry might have caught up with reliable and financially comparable drop in batteries, but I don’t have a ton of data points to back that assumption up. I plan on switching from my 440aH LifeLine AGM house bank in the near future and would appreciate any feedback, including what you might have purchased (or avoided. TIA!)

It worked out much cheaper here in Oz (one month ago) to build my own 304 AH, 24 volt LiFePO4 bank than buy drop ins.

Even had it been more expensive I would have gone with DIY build just to have control over the component quality. The videos by Will Prowse show a huge range of build quality from the drop ins, and price was no real guarantee of quality either.

I bought the bits from EEL Battery. Their communication after the sale was abysmal, but the stuff arrived reasonably fast and was as I ordered. Prices were very good.