Hello Prius Chat! So, I have been carrying out a battery re-build on a 2005 Gen 2 following a disruptive failure. Unfortunately, when using the car I'm currently getting an itermittant P3020 block 10 is weak code. My question is, does anyone know what the parameters are for this code to be set? Unfortunately, the manual describes the monitoring strategy as 'Toyota's intellectual property.' However, if anyone happens to know what it is, I'd be very interested to know. The re-built pack was made by selecting the best 28 modules from a previously replaced pack in a seperate car (aftermarket modules used, working well) and the suriving modules from the original car, used in order of capacity to achieve similar pairs for the supervision. Using charge / discharge testing, block 10s' two modules discharged 6152 mAh and 6134 mAh, discharging to 6.0V immediately following a 7500mAh charge. I believe the modules are well matched, the MFD displayes a normal battery charge pre and post code being thrown & the car behaves normally beyond the intermittant code. Ultimately, I can swap out the two modules in block 10 for the next best pair & see what that does, however, before I try that if anyone knows what the module monitoring strategy actually is it would be great to hear from you. Thanks Oracle
The HV battery ecu monitors the voltage of the 14 blocks. The ecu sets "replace battery" or "block # x is weak" codes when it sees the voltage difference between any two blocks go "too high". On good cars with no problems I see voltage difference values of 0.1-0.3V, maybe up to 0.5V for a second or two while driving hard. When a cell in a module fails, voltage diff is 1.0-1.5V. I don't know the actual monitoring thresholds that are used to flag a code, but I assume that the higher the voltage diff is, the less time it takes to code. Posted via the PriusChat mobile app.
