12V charging while HV charging

In my OP, that was after sitting overnight and before charging, during charging, and right after charging. But the before and after were with the EVSE disconnected from the car. I'll repeat it with the EVSE connected, but use the timer to delay charging and test battery voltage after resting overnight but with the EVSE connected.

I'll also check the current on my wall meter while the EVSE is connected but waiting to charge and with it disconnected.

 

More numbers:
After it sat overnight, I checked the 12V voltage. I also checked my power meter to see what the car and the L2 EVSE were drawing from the wall. For a baseline, the EVSE uses 1.2 watts plugged into the wall but not the car.

• Before connecting the EVSE to the car -- 12.62 V (1.2 watts at the wall)
• Plugged in but not charging (timer set) -- 12.62 V (1.35 watts at the wall)
• Charging -- 13.53 V (2,348 watts at the wall) I didn't monitor for a whole charge, just initial check to see that it's charging.
• Re-enable timer so it's again plugged in but not charging -- 13.2 V and slowly falling. After 2 minutes it was 13.1 V (1.35 watts at the wall as before charging)

This mainly tells me that the EVSE is only charging the 12V while it's charging the HV battery.

I'm not sure what it says about the health of my 12V battery if anything. One thing I observed was that the 12V took a temporary dip when I first connected the EVSE while the timer was stopping it from charging. So the system is doing some work as it senses the connection and makes its decisions. There is also some noise from relays clicking open and closed, which you have probably noticed in your PiPs. But the voltage bounces right back, so it's not using much power to do that.

The whole objective was to help me better understand what was going on with the 12 V system while using the HV charging system and I think I've done that. So, even though I don't know everything, I'm happy with what I've observed and hope it's at least a little informative for someone else.

 

Probably. I haven't taken a good look at it.