Let's Discuss LiFePO4 Batteries

[HawkinsHollow]

I couple years ago I bought 4 AGM 140Ah batteries from a guy that refurbishes data center battery banks. These batteries are over $400 new, I bought them for $70 each. I use them for things such as lights for camping, running the tailgater pellet grill while camping, running a trolling motor in the canoe/row boat, really anything I need off grid power for. The main drawback is they are HEAVY, like REALLY HEAVY!!

The reason for this thread is as these batteries lose useful life I would like to get a couple LiFePO4 batteries to put in their place. I have noticed on Amazon these batteries have come WAY down in price. You can now get a generic 100Ah LiFePO4 battery from anywhere between $180-$250. That is a significant decrease in price from even 3 years ago. Does anyone have experience with these batteries? Do they last?

 

[scootr]

Ensure the maximum discharge limit exceeds you application. LifePO4 is a good battery chemistry. We use them in golf carts, gate cams, RC toys, remotes and more. Some are many yrs old. The main thing to remember is store at or about 50% capacity not full like a lead acid battery.

 

[ponytug]

@HawkinsHollow Can I suggest looking at a few YouTube reviews and teardowns? There several good videos around salvaging Nissan Leaf battery packs for other uses that go into the nitty gritty.

The general issue with the low cost lithium batteries on Amazon is that many of them have been assembled out of cells that were rejects from a major producer. Ideally in any multi-cell battery, one would like to have the discharge curves as close as possible so every battery is performing equally under load. Battery management systems (BMS) can equilibrate cells within a pack to a point, but if the cells are too different in their charge/discharge properties, the pack as a whole won't perform well.

Lithium packs are going to be a lot lighter, but I would be prepared for shorter lifetimes on the "off brand" LiFePO4 batteries. I think that the cost / benefit analysis is very individualistic. I looked at replacing a tandem group 31 AGM set up that I had, and after the cost for the lithium batteries, and new high power lithium chargers, the lithium set up was about twice the cost of the AGM batteries that I ended up buying (Renogy). I just don't use it often enough to rationalize the cost difference. YMMV!

I do buy the lithium packs for use in UPSes, but not always. Often the AGM batteries can be more cost effective, even if the AGMs are on a 2-3 year replacement cycle.

All the best,

Peter

 

[HawkinsHollow]

@ponytug Excellent info. Thanks!

 

[ponytug]

Happy to share!

Good luck.

All the best,

Peter

 

[Skeletor]

We use them all the time at work. I have my own setup at my house aswell with a power station. It runs my living room and salt water fish tank setup. They are vastly superior to lead acid. Get yourself a good charger like a nice victron. Only real drawback is they don’t love the cold.

 

[square1]

Only real drawback is they don’t love the cold.

That's my main sticking (to AGM) point. Using capacity (albeit minimal) to warm the battery so it will take charge seems like a vicious cycle. In a warmer climate, I'd definitely go LiFeP04

 

[Skeletor]

That's my main sticking (to AGM) point. Using capacity (albeit minimal) to warm the battery so it will take charge seems like a vicious cycle. In a warmer climate, I'd definitely go LiFeP04

I still think it’s worth it to make the switch personally.

 

[John_Mc]

Almost bought a LiFePO4 battery for my forwarding trailer. It's a gas engine to run the hydraulics, but needs a battery to run the solenoids which control the hydraulic winch (They could have just used another hand-operated hydraulic valve, but the previous owner opted for the remote control option, which requires the solenoids, so they switch the whole thing over to electric controls.) The engine has no electrical system, so without the battery, I lose the winch function (though everything else on the loader works). Since I use this trailer a lot in the winter, I gave up the idea of a LiFePO4 battery due cold weather issues and went with AGM.

 

[newkiotiguy]

Most LiFePO4 batteries are rated to be used down to 0° F. You aren't supposed to charge them under 32° though. I have 4 of them in my boat and have never had an issue with them. I live on a pool of the Mississippi River with a nuclear power plant that keeps it ice-free all winter. I've used it in single digits every year for the last 3 years. Hope to get another 7+ years out of them.