Dead cell row can't load test?

rg12 · Dec 7, 2018

I have this 16S pack that has a dead cell (whole parallel group is 0V in the middle of the pack).
I bypassed the BMS to do a load test with my giant 1500w resistors and before the test the pack shows 61V and while connecting the load it shows 0V as if I had the BMS connected and it cut out the current.
How does it work when a cell is dead? I thought it acts like a short...

amberwolf · Dec 7, 2018

Depends on what's wrong inside, but there's a serious flaw in your testing scheme:

If you pass current thru a 0V cell, you are reverse-charging it, as if you had hooked it up backwards to the charger.

This is a really bad idea, and depending on what's wrong with teh cell(s) and their chemistry, can cause a fire.

If that's in the mddle of your pack, the whole pack could go up in flames before you have a chance to do anything about it.

So...don't load test a pack with dead cells in it.

rg12 · Dec 8, 2018

amberwolf said:
Depends on what's wrong inside, but there's a serious flaw in your testing scheme:

If you pass current thru a 0V cell, you are reverse-charging it, as if you had hooked it up backwards to the charger.

This is a really bad idea, and depending on what's wrong with teh cell(s) and their chemistry, can cause a fire.

If that's in the mddle of your pack, the whole pack could go up in flames before you have a chance to do anything about it.

So...don't load test a pack with dead cells in it.

Thats weird, it just didn't do anything, nothing got hot, no load was applied just like a power cutoff.
When I disconnected the load the multimeter was back to showing the voltage of the pack.

Dead cell row can't load test?

rg12

100 kW

amberwolf

Administrator

rg12

100 kW

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