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Strange HPWC Problem

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wdolson

Well-Known Member
Supporting Member
Jul 24, 2015
10,476
26,872
Clark Co, WA
This may have just been a glitch, or it may be the first instance of a problem that might get worse.

I drove the car for the first time in 2 days on Saturday. When I got in the 90% charge level only said 264 and it's usually 268 or 269. I was thinking the battery might need conditioning, but went about our errands.

When I got home and plugged in the car, I happened to notice an error message on the instrument screen as I headed into the house. I came back and the charge port was lit up red and the HPWC also had red LEDs showing. After some experimentation, I turned the breaker to the HPWC off and on. It worked after that and the car charged to 269 miles range like normal.

This may just be a one off thing or it may mean something is going bad in the HPWC. I was wondering if anyone else has seen this problem and if it happened again.
 
I think there is nothing for you to worry about. I've had my HPWC go red exactly once (don't know why), but resetting it cleared it up and it's been fine ever since. The rated-miles you see is totally unrelated. The car uses a complex algorithm to estimate battery charge and it doesn't always produce the same answer.
 
When you don't drive your car, charging doesn't take place until the car thinks it's required. This is typically about once every two days (in an 85, I don't know what it is for a 90). What you are seeing is vampire drain.

The red LED usually indicates the pilot circuit isn't talking properly. Sometimes just unplugging and replugging the car in fixes it. If you've had your car for some time, the contacts could be dirty. Use a Q-Tip to gently clean them.