LifePo4 Charge Performance
Thinking seriously about replacing our two GC2's with a pair of 100ah LifePo4's. Hearing a lot of chatter about how lithiums accept a charge much quicker than lead cells. Very familiar with how ou...
Forum Discussion
time2roll wrote:
I assume the Trojan BMS is of superior capability to throttle the current based on temperature.
The others are just connected or not.
Don't see it saying the BMS does that. The guide says that current must not exceed the max currents for the temp ranges, but it does not say the BMS will do that.
Seems like it is your job to have your charger's current limit match the situation. You can't adjust the current from a 55 amp converter! So if it is 35F, what are you going to charge it with? Who has a 15 amp charger handy?
My question is what happens if you hit the battery with a 55 amp converter at 35F? The Auto Shut Off safety the BMS (I guess) does, says only that it protects against "over-current", namely 120 amps.
What protects it from 55 amps at 35F? Over-voltage will make it shut down at any point, but would voltage spike immediately to 15.X if you start with 55 amps at 40% SOC, eg?
It says if you do cause a shut down, you have no power at all, so if you need 12v for the RV you need a way to have that until the LFPs can be restarted. Itinerant1 told us about his episode with that. Similar to the classic low battery at 3am and now no furnace fun time that can happen.
If you hit a FLA with a high current above its "natural acceptance rate" it just accepts what it can and nothing bad happens. I always made sure I didn't go over the max amps for my AGMs and now the SiO2 mod-AGMs, but I don't know what would happen if you go over their max amps.
I am really surprised this current limitation with LFPs has not come up with all the talk of "faster charging". Trilliums say you can only do the 110 amps if the battery is above 73F, under that and it is 56 amps.
it seems the LFP guys here have at least 200AH worth, so that would allow 100amps charging most times and they likely have 60 amp chargers so it just doesn't get noticed I guess. Still wonder what they do at 35F. 30 amp max with 200AH. Turn on the 60 amper and stick your fingers in your ears in case they explode? :) That can't be right.
