HV battery testing

Hi Randy,

I'd suggest measuring the voltage produced by each of the 38 modules when the battery is not in use. They should all be within a few tenths of a volt. Usually a failed module will produce much lower voltage.

If you see battery modules leaking electrolyte, those would also be candidates for replacement.

 

The modules are counted from the control electronics to the other side. We're looking for module(s) that are ~1.2 V lower than the others.

Bob Wilson

 

That is right. Pull the service plug out so that breaks the serial connection then you can just volt it out one by one and looking for weak one. I did mine 38 of them one by one. Good one 7.2V and up, 4 bad one 6.2-6.4V. Naturally i had battery code and at the time i did not know about individual subpack replacement and forked out $1k for a used one. Outch I came across this idea when i found Ebay listing for a used subpack and asked seller about it. He even gave me an idea on how to charge it too. I am no longer afraid of traction battery pack error code and definitely will not replace the whole battery pack again.

 

I am in process of checking my cars batteries and would like to know how difficult is this to do? New to the Prius and just bought a 2001. What do I search on ebay or where to buy replacement parts if I do find bad cells in the traction battery?

 

From what I can tell (by reading), it is not difficult as long as you're careful and wear proper safety gear. You should also be comfortable working around electricity. DC is not as dangerous as AC but, it is dangerous nonetheless. Seilerts and jdenenberg are the resident experts (and they are experts). There is some delicate wiring that is easily damaged so be very careful.

You can do a search on ebay for "2001-03 prius batteries" for replacement cells.

Are you having problems with your traction battery? How do you know its in need of repair? If it ain't broke, don't fix it. The best way to check for problems is if you get DTC's. No DTC's = no problems (typically).