Hello all: I did the load test with a 55w 12 volt bulb and a voltmeter (120 seconds per load test). See below for results of each cell module. My question is: Why could have the Toyota Dealership Diagnostics Report reflect that both Blocks 5 and 6 were "weak", but when I did the individual load test on each cell module, only cell module #10 (Block 5) is showing a big drop. I do not see much of a difference in the others. We have replaced cell module #10. Others that reflected somewhat of a drop, were tested again, but I do not notice a significant drop like in the one that has been replaced (cell module #10 in block 5). Am I missing something? I ask since as per the dealership, I should have noticed a significant drop in cell modules 11 or 12 (block #6), correct? Still confused and Totally lost See below for results. Any suggestions? (Gen 2/Prius 2004) LOAD TEST RESULTS (2ND TEST DONE ON THOSE WITH HIGHEST VARIANCE/DROP) 7.50-7.31=.19 7.50-7.31=.19 7.46-7.27-.19 7.50-7.29=.21 7.53-7.32=.21 7.51-7.31=.20 7.54-7.31=.23 7.55-7.33=.22 7.53-7.31=.22 6.01-5.72=.29 **CELL MODULE #10 in block 5-**TO BE REPLACED** 7.66-7.41=.25 **block Number 6-2nd load test 7.49-7.30=.19 7.63-7.39=.24 **block Number 6-2nd load test 7.53-7.31=.22 7.67-7.40=.27 **block Number 7-2nd load test 7.55-7.32=.23 7.63-7.37=.26 7.63-7.38=.25 7.67-7.41=.26 **block Number 8-2nd load test 7.55-7.32=.23 7.66-7.41=.25 7.48-7.29=.19 7.67-7.43=.24 7.63-7.41=.22 7.66-7.41=.25 7.67-7.43=.24 7.61-7.38=.23 7.59-7.35=.24 7.65-7.42=.23 7.65-7.41=.24 7.66-7.42=.24 7.32-7.14=.18
If you say your home's thermometer is wrong because it's 100° - & you want it to only be 70° - getting a new thermometer won't help. You better check your AC. Similarly, if you have bad traction modules, the ECU that controls cell leveling might just be shot. Not saying it is ...... just sayin'. Be careful you don't just throw good money after bad. There may be more to your issues than meets the eye. .
The suggestion depends on your goal. It you want a dependable car, but a new Toyota OEM battery pack. If you want a project car to repair but not depend on, you could replace bad modules with other used ones and re-balance & test the pack How long this repair lasts usually depends on the care taken to perform the necessary steps. A grid charger & discharger. are the recommended tools Hybrid Automotive has the Prolong brand of units which are well trusted here.
thank you. Not ready to buy a new battery yet. The Prolong charger and discharger are on their way. Just wondering why the load tests did not show any additional bad cells (in block 6 as per the dealership). Another member advised on looking into the ECU? what do you think? thanks again.
@TMR-JWAP could better advise but since you have the Prolong system coming anyway it may be worth running the pack through at least one cycle and check to see what modules stand out. He has used some Android apps that can chart out the battery statistics to help troubleshoot and assess pack health. Here is a link to some of his testing. The Prolong system will be easier than his bunch of smaller chargers. Just Another HV Battery Thread and Experiments | PriusChat
are you reading voltage while modules are under load or after removing the load? watch for voltage rebound after removing the load. ie: 1 hour I'd take the modules to lower voltages in stages/multiple tests, so you'll see more data and get closer to the types of loads the car puts on the modules in the pack. prolong is a decent pack balancing toolset, so learn as much as you can about testing modules while you have access to them individually. And of course remember the safety cautions while reassembling.
I'd suspect that is why you see different results for what the techstream report is showing. Lots more info, links and reading to similar issues Testing Tool for Modules / Cells (with load) - Step 1 | PriusChat It takes time to digest all the different descriptions and testing results. As Always - YMMV - and no surprises when it does.
I'm on the same quest that you had trying to replace individual cells on my 2016 avalon hybrid. Its very interesting that my pack also was reading weak blocks 5 and 6 but ONLY cell 9 had low voltage when i static tested it. No load test was completed. I replaced cell 9 with a used cell and moved cells from block 5 and 6 into blocks 1 and 2. Upon reassembly my check hybrid system lights stayed off.... for a while. But came on 3 times in the last 400 miles. My autophix code reader is reading the replace hybrid battery pack code but it is no longer reporting that any blocks are weak. I was expecting it to say blocks 1 and 2 were weak since i moved blocks 5 and 6 into that position but that hasn't happened yet. What ended up happing with your rebuilt battery where you replace cell 10?
