Now coming up on my 2nd year with a LifePO4 house bank (also called LFP) , I would never go back to AGM -- because I anchor
out a lot and/or sail a lot without an engine
or genset running. I had two sets of AGM batteries fail in less than 3 years from PSOC sulfation because I didn't plug
in at a slip most nights to charge the bank all the way to 100%.
If you are like me, the cost of Lithium is much less than AGM over a 10 year - or even a 6 year period. My 300AH Killovault batteries each cost $1800 and have a 7.5 year 100% replacement warranty. My last Lifeline 100AH group 31 batteries cost $465 ($1395 for 300AH) and came with a 3 year pro-rata warranty.
With that - some comments to the video:
Yes - the quality of the battery and the repuation of the manufacturer counts. It amazes me that people would buy the cheapest lithium battery on Amazon when they would only buy quality lead acid batteries with brand names like Trojan, Lifeline, Deka - or even West Marine
. My lithium drop in batteries are Kilovault brand - from a large Massachusetts
company that's been around for decades. I bought the through a marine dealer who handles the Victron, Balmar
and other marine electronics gear
you need for a quality battery installation
. Just like lead acid, there are four or five brands commonly installed in boats - pick one of those. Ask for recommendations from other boaters.
Second - all lithium house banks on boats are LFP. Don't call them "lithium" or "lithium-ion" any more than you would conflate the explosion risk of a boat with a gasoline or diesel
As Nigel says - any battery - either lithium or lead acid - should be certified to UL 1973. Low quality lead acid batteries catch fire too. There are several brands of lithium batteries so certified.
Nigel is right that lithium batteries without a heater
should not be used in temperatures below freezing. But few boats mount their batteries in unheated spaces. If you do, get a battery with a built in heater
. Again, my Kilovault has one.The same for high temperature - my Kilovaults can charge in a temperture up to 113 degrees. Unlike a car or RV, boats usually pick a cooler space to mount batteries. If you put an AGM in a 113 degree space its life will be shortened by about 50%.
BMS shutdown - much is made of this but it should never happen in a proper LFP installation
. It's certainly never happened to me in the last two years. The BMS is basically a computerized fuse. If the battery has too much current drawn, is charged at too high a voltage, or is charged too fast the BMS will cut off the power. The BMS is a smarter fuse than you have with your AGMs. While your AGM can be ruined by a too low or too high charge voltage -- that can't happen with an LFP because the BMS will protect it. You can also blow a fuse on your AGM bank that will cut off your power. Unlike the LFP BMS which resets itself, you'll need to install a new fuse on your AGM bank. Neither should ever happen if you design your system properly.
A great deal of handwaving is made about "communication". The worry is that a BMS shutdown can blow the diodes on your alternator
. This is exactly the same as what happens if you turn off your master battery switch while underway. Again, this should never happen. However there are now several good ways to protectd the alternator without having communications
in your BMS - and most modern alternators have "avalanche" diodes which aren't susceptible to this in the first place. "Communication" is just one of the ways you can protect your alternator. There are several others that are equally good.
So if you normally plug
in each night at a slip, there's little reason to go to LFP. But if you anchor
out without running a genset all night, LFP are more economical over the long run and just as safe.
And finally, these batteries pack a lot of power. If you are not very experienced around marine electrical
systems hire a pro to install it. Your insurance
company is likely to ask.