i3 generator came on when i plugged it to charge

[alpine788]

VERY ODD! My i3 2015 w REX had around 65 miles left on battery.charge. Wife brought home and plugged it in.. and I heard a sound coming from the generator... it was the generator running. I unplugged and it went off. I plugged in, it went on. Three times.. and third times the charm it stopped. Very odd. ANYONE ELSE HAVE THIS ISSUE? PLease help.

 

[alohart]

Just checking to make sure that it wasn't the A/C compressor that you were hearing. It will turn on to cool the battery pack while charging, especially in warm weather when charging shortly after driving. Like the REx engine, it is also in the rear of the car but on the left side rather than the right side.

 

[mojo]

I would be very surprised if the car's ECU would allow the REX to fire up with the car unattended. If - for example - the car were to be charged in a closed garage and that happened, you could very quickly build up lethal levels of Carbon Monoxide in the closed space. I suspect that Art is correct and it's the battery cooling system that was running.

 

[alpine788]

Thanks guys! That makes perfect sense...
Just that I came home from a long vacay (17 days) and my sce bill is $795!!!! i WAS thinking that REX was juicing me to death by hvac.... or generator.
How long does it take for it to turn off the a/c unit do you supposed? Thanks again for the help

 

[alohart]

How long does it take for it to turn off the a/c unit do you supposed?

Depends on the temperature of the battery pack and the charging power you're using. You could wait for an hour or so after parking before beginning to charge to allow the battery pack's temperature to drop a bit. You could try reducing the charging power in iDrive if you have plenty of time to reach your charge level goal. Charging with the A/C compressor on would increase the total charging time and energy consumed because some of your charging power would be powering the A/C compressor rather than charging the battery pack. The few times the A/C compressor has turned on when I started charging at home, I quit charging for an hour or so which worked to prevent the compressor from running while charging.