LIFEPO4 Battery discussion thread

cavedog said:
So the UVP disconnect means that it leaves the pack with roughly 20% capacity left in the other 15 cell packs.

View attachment 1910457

I'm just going to use it like this and see if it ever improves but I have my doubts.

If I'm really keen to fix it I will get 6 of those cells and see if I can chisel the busbar off and then just drill small holes in it and replace them with cells that have studs on them for example. That would probably be the cheapest way to repair if it doesn't get fixed. Replacing the whole pack with prismatic will probably only be worth it if I buy cheap 2nd hand cells or if the entire pack fails.

View attachment 1910458
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What happened to the top balancing?
 
wingnut771 said:
What happened to the top balancing?
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Yeah that is an option if it gets to that. Replacing is a last resort. I'm just thinking it's going to be quite the job even to do top balancing given how this pack is I need to remove it from the case and the wires are soldered onto the busbars not bolted so I need to disconnect it at the bms. To do that I need to remove the bms its quite a process.
 
cavedog said:
Yeah that is an option if it gets to that. Replacing is a last resort. I'm just thinking it's going to be quite the job even to do top balancing given how this pack is I need to remove it from the case and the wires are soldered onto the busbars not bolted so I need to disconnect it at the bms. To do that I need to remove the bms its quite a process.
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What is voltage of cell group at 56V?
 
Battery 3 still hasn't woken up from its UVP alarm... I'm keen to see if it automatically wakes up and starts accepting charge. If its constantly going to need manual intervention it can be a problem.

Screenshot 2026-05-25 093944.png
 
wingnut771 said:
What manual intervention?
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Okay no it wakes up automatically and exit fault mode when the other 2's voltages goes 200mV higher then it starts charging.
 

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wingnut771 said:
What manual intervention did you do before?
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Switched the battery breaker off then switch bms off wait a minute or 2 then on again and it wakes up unless it pulls power from it then UVP for cell08 kicks in again.
 
Most people have seen the balancer doing around 100mah to 200mah

Lets say the battery needs to balance out 10ah

At 100 mA (0.1 A):100hours
At 200 mA (0.2 A):50hours

Rushing it to much being impatience.

The battery does not sit at balancing voltage 24/7 either
 
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FIRE OPS SA - Batteries catch fire at Standard Bank offices in South Africa

“Fire Ops teams were dispatched at approximately 09:00, where they encountered an intense blaze inside a container housing two 300kWh lithium-ion battery racks,” said Koekemoer. “Despite nearly two hours of conventional firefighting methods, the fire continued to escalate — a behaviour typical...
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From Powerforum
 
denmendez65 said:
That is a good price. I wonder if it comes with a BMS? Curious how they got the price so low.

I paid between 1 and 1.2k for each battery. Was buying them in stages over a 3-month period. Spent just under 12k for all 10 if I recall correctly.
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They always come with a BMS. I think its cheap because of 60A discharge limit.
 
wingnut771 said:
They always come with a BMS. I think its cheap because of 60A discharge limit.
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I dont think so. You can build batteries without a BMS. There were some videos I watched a long while back of people building their own without a BMS. You dont need one.
 
denmendez65 said:
I dont think so. You can build batteries without a BMS. There were some videos I watched a long while back of people building their own without a BMS. You dont need one.
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Of course you can. You can also mix 15s with 16s if you really want to or LFP with NMC.

Were they selling them on the internet? Lets see them offer a warranty with their strategy.
 
wingnut771 said:
Of course you can. You can also mix 15s with 16s if you really want to or LFP with NMC.

Were they selling them on the internet? Lets see them offer a warranty with their strategy.
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I dont see a warranty on the one cavedog posted.
 
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