Battery reconditioning - Gen2

Reconditioned hybrid battery failed after 14 months (just outside the warranty).

I removed the hybrid pack, identified failed (and subpar) cells by out of range voltage/resistance, and by cycling individual cells to ID those with poor discharge (below 5000 mAh. Those cells were removed and replaced with reconditioned & tested cells.

When I put the pack back together and buttoned up the car, everything ran fine (at first). Dr Prius app tests showed the battery was in good condition with capacity estimated at 100%+. After a few trips, the red triangle of death returned, P0A78, P0A94, P3000, P3004. Dr Prius showed out of range voltage in block #14, and later out of range resistance in block #3. I did put the weakest cells at either end of the pack, strongest in the center.

I’m totally frustrated. Suggestions appreciated on how to more thoroughly test cells please! I used Volt/Ohm meter testing. Plus 3-5 cycles on each cell with Tenergy T180W with tight records on discharge/charge cycles.

Any other constructive suggestions are welcome!

Thank you in advance!

 

I should have added that i replaced all bus bars and nuts. The existing harness has some corrosion on it…should I replace that?

 

Thank you. New wiring harness kit ordered. Inspection of the pack post removal (#2) shows significant corrosion on bus bars and terminals that wasn’t present the first time it failed. It makes me think the bus bar replacement kit I ordered from Amazon must’ve been junk. I removed corrosion with a wire brush.

I did perform a deep cycle of all cells prior to reassembly and removed all cells that were unable to reach a max discharge of at least 5000 mAh. However, I was over-charging them (6800 mAh) to avoid interruption in the cycle (charger interrupts cycle at max capacity reached).

I will do the trickle charge! Great advice! Much appreciated!