Fully charged but charger keeps turning on

cecil-t · Oct 31, 2018

I have a 2017 FFE. Last night, as (almost) always, I plugged in the car to charge. Value charge kicked in at the specified time and car was charged in the morning.

I didn't drive it today, just kept it plugged in, past the Go Time. This evening I'm working in the garage and keep hearing the EVSE click on and off, with corresponding clunks from the car.

I wander over during one of these cycles and the car is drawing 0.23 kW on the display of the charger (0.9 amps, 245 volts). Cycle seems to repeat fairly quickly, maybe 2 minutes on and 3-5 minutes off.

Any ideas what is happening? I don't know if this is good, bad, or otherwise. Also don't know if it just started happening, or if it's been happening and I just noticed it.

Ambient temp is maybe 50°F in the garage.

triangles · Nov 2, 2018

Sound to me like the TMS is kicking. It heats the battery when it's below 50F and cools it when the battery is above 95F

cecil-t · Nov 7, 2018

triangles said:
Sound to me like the TMS is kicking. It heats the battery when it's below 50F and cools it when the battery is above 95F

Thanks. I didn't realize the heating began as soon as 50F.

triangles · Nov 8, 2018

Yeah below 50F lithium ion batteries start to get weaker and somewhere near freezing they really fall off a cliff. I learned this the hard way using a lithium starting battery on my motorcycle that I ride year round unless there is snow/ice on the road. Much below freezing and I'd have to "warm up" the battery to get it to even turn the engine over.

gunther · Nov 12, 2018

Could be the TMS, but another possibility is it could be kicking on to charge the 12V battery. When my 12V was basically on its last leg and couldn't hold a charge hardly at all, I noticed the EVSE clicking on from time to time. If you haven't changed your 12V battery in a while, you might want to get a new one before it causes you real problems!

Paul