Thought I share a couple of hybrid battery test results. I found the test here Predictive battery failure analysis for the Prius Hybrid Basically, monitor the max and min voltage from all the cells while discharging the hybrid battery. You do this by putting car in reverse + step on brakes, wait until ICE stops and step on the accelerator and until ICE comes back on. The time duration (depends on starting SOC) and voltage different curves shows the health of the battery. 2001 Prius 208k miles with original battery. 55% starting SOC. Test lasted 2.5 min before my Techstream tool ran out of memory. ICE started fairly soon after that. Basically about 0.2-0.3V difference. Not bad. Test starts at the line with down arrow. Cell resistance is between 0.021-0.024 OHMs. 2007 Prius 137k miles with original battery Ran the test 3 times. Each time about 100+ seconds so total about 5+ min worth of testing. Max voltage difference is 0.2V So my understanding is 01 looks reasonably healthy and 07 looks pretty good. Is this correct understanding?
Very cool! I'll have to pull the current and do a chart like yours. Regardless, I'm assuming grid charger helps at these miles and have read about them before. Need to figure out how to setup one and the associated dangers of playing with these batteries
Yes and some background. The shop manual, Volume 1, describes how to do this test. There is a hack to edit one of the Techstream files to increase the recording time. But you can trim the amount of data recorded and get more depth. It is not hard to quickly save and restart recording. Bob Wilson
