Does charging the car also keep the 12v battery topped off?

[Anonymous]

I only drive on weekends and would like to keep the 12v battery from going stale. If I keep the car plugged in, will the 12v battery also be charged?

 

[whomadewho]

The Manual specifies to keep the car plugged in for (up to) 4 weeks of storage, so presumably the circuitry keeps the 12v optimal while plugged in.

 

[suparukuibi]

The Manual specifies to keep the car plugged in for (up to) 4 weeks of storage, so presumably the circuitry keeps the 12v optimal while plugged in.

Sorry, but this ^ is guess.

Does anyone know the answer?

 

[CCIE]

The 12V battery is charged while high-voltage charging is active. However, once the HV battery is full, the 12V battery is no longer charged/maintained. That's why the manual says to discharge the HV battery to <50% and disconnect the 12V battery if the car will be sitting for a month or more.

 

[NORTON]

I thought the 12V battery is maintained through the APM when the car is plugged in. Why wouldn't it?
And of course the HV is maintained at the proper temp range.

Do you have a multimeter? Pop the hood and see what the voltage is on the 12V battery when plugged and when not plugged in.

 

[CCIE]

I should probably re-state and say the 12V battery will be maintained whenever the car is drawing power from the EVSE. So, if you do a remote-start, or the car pulls power to maintain battery temp, or anything else that triggers the EVSE HV power relays to close, then the APM would also charge the 12V battery (if needed).

 

[NORTON]

I should probably re-state and say the 12V battery will be maintained whenever the car is drawing power from the EVSE. So, if you do a remote-start, or the car pulls power to maintain battery temp, or anything else that triggers the EVSE HV power relays to close, then the APM would also charge the 12V battery (if needed).

Agreed. Even though the green dash light is flashing the EVSE may not be providing AC voltage to the car.
As you said, when you initiate a remote start if you are near the EVSE you can hear its big relay close.

 

[Nashco]

If you are driving once a week you have no worries about your 12V battery. It is living an extremely nice life compared to the 12V battery on an ICE car and will last you a very long time.

On the other hand, if you aren't driving during the week, it is best to plug your car in to charge at the end of the week, just before you drive it on the weekend. It's only a tiny difference in high voltage battery treatment, but over years of doing this you will be helping the high voltage battery last better.

Bryce