Fixing Hybrid battery.

What's the mystery? You found another module that's low. This will happen over and over again as the modules age.

To make a longer lasting repair, you would need to balance the entire pack when you're done replacing the weak/failed modules.

 

are you testing the cells under load?
a volt meter alone is not the way to do it

 

Further, module #28 at 7.43V is also getting low compared to the high module voltage of 7.76V. A difference of more than 0.3V between high and low may trigger a fault code.

 

With the traction battery installed and using Mini VCI to track module pair voltage, one way would be to make the Prius READY, shift to R and hold the car stationary with the parking brake and foot brake. Then floor the accelerator pedal to run the powertrain and watch the module pair voltage as reported by Mini VCI.

Another way when the battery is out of the car would be to fabricate a load of some sort such as light bulbs across the battery output, then use your meter to measure voltage of each of the 28 modules. However you would need several bulbs to create a reasonable load. For example, since the battery voltage is ~220V, regular 120V household bulbs need to be put into series. Suppose you had four 500W halogen bulbs available for making a load. You would wire two bulbs in series so that they would withstand the battery voltage. Then you would assemble another two bulbs in series, just like the first two. Then connect both assemblies in parallel across the battery. The net result is that your load would dissipate ~2000W and require ~9A current. That should present a pretty good load for the battery.

 

I remove the pack from the car and I use an old fog light 12 volt, I hook it directly to the cell (2 of the modules) for 2 mins than read the voltage...bad ones will drop to around 11 volts than I check the individual modules, one will be bad in most cases.around 6 volts.i have only rebuilt 3 packs so far and this has worked for me, so far no rebuilds. im sure there are other ways but i used stuff I had around the garage..if you see the modules swelling that's another way to tell they are bad

 

So what code or codes does it give you?

LG G3 T-MOBILE phone ☎