A graphical analysis of my Insights Subpacks after I got an IMA and Check engine light. The pack did not ever do recalibrations, and set the IMA code several days before setting the check engine code.
P1447 set the IMA, P1449 set the check engine. A system reset would not clear the codes. Each subpack was charged most of the way, topped off, then discharged while watching the temperature and voltage across each cell.
I looks to me like subpack 10 and 12 are the guys that set the code. I hope to be able to replace the cells that are bad, cycle and rebalance the rest and try the pack back in the car.
Please feel free to comment on the graphs with your opinions about what they show, my comments are very preliminary since I have only put them through a single cycle so far.
I charge @ 5-6A, and can do a high rate charge of 30A. The discharge is at 30A, and can be increased to ~70A.

Graphing the cycle


charge discharge charge

The new code has the ability to log both the charge and the discharge, and with the automatic discharger, we can do automatic cycles to fully exercise the pack right on the bench or in the car.
The graphs show the log from cycling the prius pack below. Notice how we start sampling the discharge at 6 second intervals instead of minute intervals so we can more accurately and quickly detect a cell drop out. seems to work well. The graph also shows how the plateau detection with a 10 minute sample time does not do as good of a job as the 30 second sample timer. Also the graph shows how one can set the cutback higher to speed the charging process, but better not go so high that the topping never starts. A good reason to graph the charge so you can better determine the best cutback for your pack.
I cut the topping short on the final charge as it was 2AM and I needed to go to bed.
Will run another cycle

(Posted 12/29/2011 by mikey)

Smart discharger


Cycling a Prius pack

To fully cycle the packs and therefore recover as much capacity as possible, I am exploring two possibilities. the first is a charger controlled load for the full pack. A 250VDC power mosfet with an optically controlled gate is the HV switch, and the present configuration of the dis-charger is a series parallel configuration of six 100W tungsten bulbs.
This is about 2 amps at 144v. The charger automatically charges to the plateau, then turns the charge off, and runs a timed discharge to a setable minimum voltage. If the discharge rate of change accelerates due to a cell drop out, the discharge will stop, and the charge starts again. The charge MAH will hopefully measure the improvement in pack capacity as the pack gets into balance, and the cells with memory effect get exercised to increase their useable capacity. The second will be a diagnostic discharger which will discharge all sticks separately at the same time and compare capacity, as well as fully discharging all sticks without danger of cell reversal.
whole pack discharger

(Posted 12/28/2011 by mikey)

Time to get serious about determining what actually fails in the sticks


Getting ready to start testing

Since Hybrid battery repair has abandoned the pursuit of cell level rebuilding of the subpacks, and I have already built the welder, and other fixtures and test systems,that he does not want, I will use the equipment to dig deeper into determining how the subpacks look at the cell level.

A look at the traces below will show that many subpacks only have one cell that is a bad actor, others show overall deterioration that may or may not respond to charging.
Time to pin down some of the failure modes, and with the new smart chargers, we should be able to troubleshoot a problem pack and determine which sticks are acting up, and then which cells within the sticks require replacement to get the pack back into a useable condition for the least cost.
I grabbed all of the packs and sticks I have, and have assembled them so I can begin the testing.
The automatic whole pack discharger is working well with the 6 100W bulbs, so I will run capacity recovery test on all the packs I have available to see what we see.

(Posted 6/20/2010 by mikey)

Zap test of MP 10


Zap test on MP10

MP 10 has some obvious issues, so I tried the zap fix to see what would happen.
I started the run charging at ~5A, with a pulse of 30A. Next I zapped C2 and C4, which caused no change to C4, but jumped C2 up a notch.I ran that with 5A and a pulse of 30A. Finally I zapped each of the rest of the cells and did the same 5A and 30A pulse.
This seems to have jumped the voltage of all cells so the C2 again fell to the bottom of the group.

(Posted 3/29/2010 by mikey)

Subpack 20


Subpack 20

(Posted 3/27/2010 by mikey)

Subpack 19


Subpack 19

(Posted 3/27/2010 by mikey)

Subpack 18


Subpack 18

(Posted 3/27/2010 by mikey)

Subpack 17


Subpack 17

(Posted 3/27/2010 by mikey)

Subpack 16


Subpack 16

(Posted 3/27/2010 by mikey)

Subpack 15


Subpack 15

(Posted 3/27/2010 by mikey)

Subpack14


Subpack 14

(Posted 3/27/2010 by mikey)

Subpack 13


Subpack 13

(Posted 3/27/2010 by mikey)

Subpack 12


Subpack 12

(Posted 3/27/2010 by mikey)

Subpack 11


Subpack 11

(Posted 3/27/2010 by mikey)

Subpack 10


Subpack 10

(Posted 3/27/2010 by mikey)

Subpack 9


Subpack 9

(Posted 3/27/2010 by mikey)

Subpack 8


Subpack 8

(Posted 3/27/2010 by mikey)

Subpack 7


Subpack 7

(Posted 3/27/2010 by mikey)

Subpack 6


Subpack 6

(Posted 3/27/2010 by mikey)

Subpack 5


Subpack 5

(Posted 3/27/2010 by mikey)

Subpack 4


Subpack 4

(Posted 3/27/2010 by mikey)

Subpack 3


Subpack 3

(Posted 3/27/2010 by mikey)

Subpack 2


Subpack 2

(Posted 3/27/2010 by mikey)

Subpack 1


Subpack 1

(Posted 3/27/2010 by mikey)