can LiFePo4 be totally discharged (from a dealer)

[pianotuna]

Hi all,

This video is pretty clear. It seems it would be best to have a battery management system that would not go below 20% (1/5th) state of charge.

https://www.youtube.com/watch?v=HCIlaXaVeF0

[time2roll]

Easy to have the BMS cut at 20% capacity if you build your own.
Can sit at 20% for 6 to 12 months without issue.
Dealer proof 😉

[dougrainer]

My take on the video is what I KNOW and have experianced for both Li and AGM batteries for the past 10 years. LI are GREAT as are AGM's. BUT you can fully discharge a Lead acid DEEP CYCLE battery and as long as to do a slow steady recharge the battery will resume almost 100% efficiency. It has lost some of its life cycle, but minimal. Li and AGM, you completely drain them dead and leave them dead for more than a few days, well you now have a very heavy small boat anchor. They will NEVER recover their life cycle or even stay charged. This has been a big headache trying to get the idiots in our sales dept to keep our B vans that now come with LI(used to be AGM) plugged in and charged. They rant and rave when they have to buy NEW batteries for when they sell that Motorhome and we try to educate the Sales manager, but they keep buying new batteries because WHY? Because the Makers of the Li and older AGM KNOW the only way a NEW battery could be bad because they were allowed to discharge completely. Doug

[Lwiddis]

I have read from a number of other sources that like wet batteries, the depth of discharge greatly influences Lithium battery life.

[3_tons]

I’m not sure why he chooses to use the word ‘Lies’?? After watching his presentation, seems to me like an overstated use of a ‘trigger word’ to illicit audience clicks, while in the end he’s merely providing some fair minded information that might seem self-evident in actual practice…Another case of unnecessary hyperbole (trolling confirmation bias??) subsequently cloaked within some facts…’Viewer Discernment Required’…

Either way, in the ‘real world’ of drop-ins, the actual battery capacity can often be slightly greater than even the mfg’s advertised spec’s - Case in point: my LFP bench test at 7% over mfg’s spec capacity, so even at an indicated zero SOC, 7% capacity remains in reserve (meaning longevity unaffected), suggesting the advantage of bench testing…FWIW, I’ve even brewed the Keurig at 125amps at zero % SOC…

A 20% SOC BMS Cut-out, really?? (why so??)

3 tons