How to detect on Prius a weak cell

Everyone loves a happy ending. Share your diagnostic success stories here.
Post Reply
victor2k
TwoWaves
TwoWaves
Posts: 250
Joined: Thu Jan 28, 2016 7:17 am

How to detect on Prius a weak cell

Post by victor2k » Tue Apr 24, 2018 9:47 am

Hello,
The car is a Toyota Prius /NHW20/2009 year with warning lights in dashboard.Using a scanner I see in HV Battery ECU P0A80-Replace Hybrid Battery pack.
P0A80.PNG
Then I looked at the freeze frame for this fault code.
BLOCK 05.PNG
Using this I found block 5 and 8 faulty(the voltage drop too much in the discharging phase).The HV battery use 28 cells(7,2v each,6 elements in one cell),in diagnose you will see 14 blocks(2 cells in 1 block)
Now is the time to find the faulty cell.Both cells were taken from the same HV battery(block 05),so the discharging rate must be the same. I placed in series this two cells and a 21w/12v bulb- the discharging process was captured with the scope:
the voltage from a good cell on channel A,
the voltage from a bad cell on channel B,
the discharging current on channel C
Toyota_Prius_2009_Petrol_20180424-0001.psdata
(3.43 MiB) Downloaded 125 times
At the minute 15 you can see a drop of cell voltage(only at the bad cell) so the bad cell was discovered.
The voltage drop is easy to see,the current drop not.
How can be used this infos to calculate the cell capacity(a new one must have 6,5Ah)?Will be needed more datas?Just tell me what you need ...
Best regards.

victor2k
TwoWaves
TwoWaves
Posts: 250
Joined: Thu Jan 28, 2016 7:17 am

Re: How to detect on Prius a weak cell

Post by victor2k » Thu Apr 26, 2018 4:30 pm

Hello again,
Today I made a full discharge,do not try this at home!
Here you can see how the different 1.2V cells fails in the discharging phase...
here is the bad cell
Toyota_Prius_2009_Petrol_20180430-0001.psdata
(417.52 KiB) Downloaded 91 times
And here is other cell
Toyota_Prius_2009_Petrol_20180430-0002.psdata
(511.55 KiB) Downloaded 74 times
Attachments
IMG_20180430_124702_HDR.jpg

Post Reply