Yesterday I just picked up a scan gauge 2 and programmed in some prius specific codes and played with it on my commute. I was very interested in the HV battery current to maximize regen braking but when I also switched over to the HV voltage it was jumping around a lot which didn't seam normal to me. It danced around between 193v accel at about 40amps to 255v braking at about -53a. When I stopped the SOC was 57.5% and 6 bars with a voltage of 215v. Are these normal readings to get? And if so is there anything that I can use the scan gauge to watch out for possible HV battery failure. I've still got 1 year of hybrid system warranty and in a few weeks the prius will become the wifes daily driver instead of mine so I'd like to be able to test the HV battery if I can. Also I did a test of the 12v and it's around 11.5 after 8 hours, doesn't drop too low and I will be planning on taking it out and reconditioning it. Also the HV current draw is about 1.2 amp with the vehicle in the ready position and the ICE off. Thanks
Your HV battery readings all look similar to what I see on my Gen III 2010. From what I have read, when the HV battery begins to go you begin seeing wild swings between SOC highs and lows. I would think you would see the wild swings on the battery voltage on the SG also. Your 12V battery either needs reconditioning or replacing. Anything under 12V after 8 hours is not good.
Sounds normal. Things to watch: battery temperatures (there are 4 probes -- anybody know the xgauges for those?), cell soc delta/delta soc, battery block voltage highest, battery block voltage lowest, Soc. Being in Ontario, Canada, battery failure is much less likely, as compared to Southeast or Southwest US.
I put the battery temp max (in C) code in and the first day it was 12 and 14 on my two trips. Today it got a lot warmer and it was 19 and 21. What is the upper safe limit? I also used the code for measuring the difference in cell voltage but it keeps reading 0.0 and I would be expecting at least a minor difference so I'm thinking that may not be working proplery. Overall though I must say I am loving the SGII. I have ICE RPM, HV battery current and TPS on all the time and at start up I have engine coolent temp to know when I'm at full operating temp. That one I then play around with as I drive. The HV current is interesting because it's like an instant fuel economy gauge for the battery. So far since getting it my avg on the tank has dropped from 5.0l/100km to 4.6. My avg on the SGII is about 4.4.
Allowing for a few volts due to changes in state of charge, what have you got, a (delta V)/(delta I) of about 600 millohms. Divide by 28 and that's about 21 milliohms per cell. I think that sounds somewhere close to the mark.
Can you tell me or point me to more information on this line of your quote? "Yesterday I just picked up a scan gauge 2 and programmed in some prius specific codes and played with it on my commute." I have the GoPoint GL1 cable that connects OBD-II to my iPad and there's apps for it, but when using it I don't see any information specific to the Prius or Hybrid system, etc. What should I buy to be able to monitor the specific Prius information like you're mentioning?
This is what the HV battery voltage looks like during a normal commute. RIKLBLOG - My Commute As A Voltage Graph The wide variation is largely due to the high current across the internal resistance of the battery. Richard
