[Steverino]

I'm pretty sure if you have it set to "do not charge now" then the car won't draw power from the wall. Otherwise, if plugged in the car will heat the battery depending on temps. See Volt thermal management system temperature band?

also

Volt thermal management system temperature band?

Battery Management and Cell Balancing The pack is divided into 4 distinct management blocks each with there own group of 24 triplets to monitor. This is accomplished by four interconnected Battery Interface Control Modules (BICM). Each BICM monitors the 24 voltages and 4 temperature probes...

www.gm-volt.com

 

[Lug_Nut]

I've occasionally, on cooler days, seen my power meter indicating 40-ish watts of consumption during 'peak', hours after my off-peak charge has completed. I've presumed this was battery temp maintenance. I suppose the battery isn't being 'charged', so my setting of "off-peak only" for charging has nothing to do with when a battery warmer might be active.
I have no idea how long it was pulling before I noticed, nor how long it was until this ended. I'm also not concerned enough to unplug to save this draw.

 

[Steverino]

I've occasionally, on cooler days, seen my power meter indicating 40-ish watts of consumption during 'peak', hours after my off-peak charge has completed. I've presumed this was battery temp maintenance. I suppose the battery isn't being 'charged', so my setting of "off-peak only" for charging has nothing to do with when a battery warmer might be active.

If the car is plugged in with less than 100% State of Charge, it's going to charge. Setting the car NOT to charge until some later hour would of course prevent that. Your data seems to indicate the car can and will pull power from the wall for thermal management or other applications not directly related to replenishing a low battery. If so, cool beans and thanks for the info!

 

[fhteagle]

Thanks for the links, @Steverino and for your experience @Lug_Nut . I did search this forum, and read quite a few threads but search didn't seem to offer me ones that old. Not sure I got the exact answer that I was looking for. But I'm inspired by the testing and measurements that were done back in the day to understand this crazy engineering project known as the Volt. Fortunately my OpenEVSE has an amp display with <30 second update rate, and a total energy delivered in the current session. I'll do some more specific checking once it gets cold enough here for the battery to possibly want to heat overnight.

 

[fhteagle]

Quick update on this:

It hasn't really been cold enough to guarantee the volt will want to heat overnight yet. Will keep watching and see if I can make a definitive conclusion.

More testing required

 

[fhteagle]

Okay, so I got my OpenEVSE connected to my Homeassistant instance, so HA is recording what the OpenEVSE does. That and it's finally cold enough here that the battery is wanting to heat overnight.

So I can confirm that the Volt definitely will heat the battery while stationary and plugged in during the mid-peak rate time window.

I'll rearrange my settings and see if it does heat during peak too.

 

[Lug_Nut]

I've occasionally, on cooler days, seen my power meter indicating 40-ish watts of consumption during 'peak', hours after my off-peak charge has completed.
I have no idea how long it was pulling before I noticed, nor how long it was until this ended. I'm also not concerned enough to unplug to save this draw.

The EVSE and power meter are in the garage with the Volt plugged in outside. I can hear the relays in the EVSE click and it's that sound I notice. I've been spending more time in the garage recently working on another project and am able to report that I've seen as much as 1500-ish watts of power being pulled during my peak rate hours, with a fully off-peak charged battery.
This grid pull doesn't last long, maybe 5 minutes and then it tapers down before ceasing. I don't interrupt it despite being at 'peak' rate. I figure it's either 1500 watts (150 Wh?) from the wall, or it'd be 1500 watts from the battery. That would mean I'd have to put pull 1700 from the wall later to get the 1500 back in. The cost difference for .15 kWh peak and .17 kWh off-peak just isn't worth unplugging.

 

[fhteagle]

Confirmed that the Volt will thermally manage during peak rate periods. I guess that settles that.

Back into the freeze protected garage it goes...