After a few hours charging, maximum amps drops significantly. Any ideas?

After a few hours charging, maximum amps drops significantly. Any ideas?

I'm having an intermittent problem when charging on my 60amp 240v setup.

After a few hours, the maximum amps drawn drops from 40amps to 33amps or, currently (no pun intended), 23 amps. I enter the car and try to increase the maximum, but it is grayed out.

I also notice that my portable charger is VERY hot to the touch. I have no idea if this is normal or not.

Lastly, this problem popped up post 4.4 firmware upgrade. Not sure if it is a correlation or a causation.

Anyone else ever see this?

jat | April 28, 2013

Are you doing standard charge or range charges? If the latter, then it is expected that it slows down charging as you get closer to full.

When you say VERY hot, is it too hot for you to hold indefinitely? If so, then that seems like a problem. It should be noticeably warm, but not so hot that you couldn't hold it as long as you want.

pwasserman | April 28, 2013

Yes. WAY too hot to hold for more than a five seconds.

This is happening right now in standard mode on an 85 when the battery is only at 79 miles.

Costa Mesa Service Center checked the logs on Friday remotely as I needed the car for two 220 mile round trips this weekend (Orange County to Lancaster in range mode.... made it home with 30 miles to spare each time!). They saw the problem but obviously could not check it out remotely. He mentioned it might be the charger and wanted to check it out in shop. I'll bring it in this week, but it sounds like it is probably the charger.

jat | April 28, 2013

Yeah, my guess would be some problem with the mobile connector, and it is throttling the current based on an internal temperature sensor. It should be easy to check by charging with another mobile connector, which they can do at the service center.

Vawlkus | April 30, 2013

If it's getting that hot, you're heading for thermal cutoff. There's gotta be a bad connection in there for that much heat to be generated, and you need to get that found and fixed or replaced ASAP.