Battery running hot

Is the fan running? Or just clean?

 

There is nothing you can possibly have happen to the inverter that's going to cause uneven temperatures in the HV battery.

The Gen 2 HV battery has 3 temp sensors that mount on the underside of the battery (the air outlet plenum). One mounts on the bottom of the module nearest the ECU end of the battery, one mounts near the middle module and one mounts at the far end (block 1).

Each is just a thermistor that has a resistance change based on temperature. Quite often, I see the sensor on block 1 get damaged because that's where everyone jams there hand for lifting the battery when swapping them out, bit I don't currently remember which sensor matches to which number on that app.

Your likely issues are a damaged sensor (usually wiring gets bent or cracked) or an actual high temp condition due to blocked air flow or inadequate airflow. Hard to tell without actually seeing the battery. There's a handful of components that are installed in the case specifically to direct airflow. Sometimes they get missed on rebuilds. There's always the chance that the actual module with the sensor mounted to it is running a bit hot.

 

Does the battery actually get hot? If you disassemble the back of your car to gain access to the battery, then drive until the app shows it as hot, then pull over, shut down, and feel the pack (or use an IR gun to measure temps) is it actually really hot in one area?

If the pack really is getting hot, does a dog or other source of fluff or hair ride in your vehicle? If so some of that might have gone through the fan and packed up parts of the battery to restrict air flow. Also, you said this was some sort of rebuilt battery, so who knows what the inside was like when you got it. Perhaps it would be worth opening it up just to see if there is some obvious problem inside.

 

How dirty was the fan?

 

The timing of this thread is perfect for me. I just finished assembling and installing a battery pack from Hybrid Reconditioners in Philadelphia. I have the MFD out to be replaced/repaired so I'm using the Dr Prius app to get up to speed with this car. Been driving it around here on the Big Island (we have some huge hills as well!), and observing that braking while going down one hill in particular which drops from 1000ft to around 500 in a half mile the voltage goes into the red (247 was the highest I observed), all the bars go red when I brake. Battery temps are not as high as Wrecit, more like 110 or so. But since I'm a newbie with this car I was concerned about both the overvoltage and battery heat. I know the fan is clean and working, I can hear and feel airflow, so my question is, is this normal and to be expected with charging and braking on steep hills.

 

Do you ever use B transmission mode on downhills instead of braking?

 

Don't be concerned about the voltage going "up into the red". The battery and hybrid ecu's will take care of things. Voltage increases during charging as the battery is "filled". If voltage gets high enough (State Of Charge is at the max value) then the car will stop charging and rely more on the friction brake.
Your temperatures sound normal, and you mostly want to watch the voltage differential as that usually is the first indicator of most HV battery problems.

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