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Strange charging behavior, timer shut off, home location lost, pulling some current even when waiting for timer to call for charge.....

66 views 2 replies 3 participants last post by  hightech-guy  
#1 ·
I am new to the EQEV so not that many charging sessions. I setup charging timer to be ready at 6 AM about 14 days ago. Charged once to 80%, next night I requested 100% in anticipation of a longer trip. Followed that by an 80% charge the next night. Gave me 81% -- no problem.

Next 7 days or so were local driving. I was very pleased to be right at 35 miles for every 10% of battery ( you learn to run computations like this when driving a Nissan Leaf for 13 years). Did not plug in at all. Down to 46% today

Plugged in tonight for a modest trip tomorrow. Left things at 80% Changed NOTHING from the charging session a week ago.

Vehicle starts "charging" immediately at 8:45 PM. Light on EVSE goes on that its charging. I am befuddled. I try plugging in/out, several restarts and what's weird is that the whole delay charging screen was GONE. It was like I had never established a home location, never setup any charge times or 80%. ALL GONE.

I go to my computer and read some threads here, return to my car, and reset my home location and then delete and re-enter my charging times.

Plug car in, and bang, charge light on the EVSE again lights up.

Here's what gets a bit more confusing for me. When I plug a Leaf into the EVSE with a delay setup in the vehicle, no charge light on EVSE. But tonight, I go to my EVSE web monitor (Its a fried Juicebox 40 with OpenEVSE MoBo retrofitted) and I can see this strange fluctuating current. The OpenEVSE allows me to see instantaneous current (well I think refreshes every 1 second). Varies between 0.7 amp and at times as much as 15 amps 240v.

So this kind of explains the charging light -- the car is still pulling some amperage. I assume running some fans or whatever its doing. It continues to make some noise for a while after driving. I assume this is normal for an EQEV -- and yes, its shut off.

Chevy app says its paused and the % charge has not budged now in 45 min since I deleted all the settings and started over.

Anyhow, read any number of threads about charging strangeness. Dunno how the settings got changed. Seems to be at least not charging now, BUT for folks with a TOU plan, just why its pulling some current is mysterious, and problematic.
 
#2 ·
There are two reasons that I can think of that the car will pull power when not "charging":
- 12V battery maintenance
- traction battery temperature management

The 0.7A corresponds to what I see that I attribute to 12V battery maintenance. You need to draw that amount for 6 hours to accumulate 1 kWh. I have never observed this draw for that amount of time. Even then, 1 kWh at a peak rate is negligible.

The 15A draw I haven't seen, but I don't live in a high temperature are that would see battery cooling take place. I have not had the chance yet to monitor current during a cold weather battery warming event.

My advice on the charging schedule:
- remove home location
- go from park to drive and back
- enter your schedule
- go from park to drive and back
- set your home location
- go from park to drive and back
- enter your schedule
- go from park to drive and back

Hopefully even if the car loses sense of its location it will use the "same" non-home schedule.
 
#3 · (Edited)
Couple things likely occurring here...

First, the GM Ultium EV's will activate the EVSE outside of the preferred charging times for various reasons. You usually see this when you first plug in, even if you have scheduled / charge-later charging selected. Some of this is checking if the EVSE is ready to deliver power, in which case it clicks back off in a minute. But other times it will stay on for many minutes, starting at full power, and then trailing off to just hundreds of watts. This is a battery safety testing hold-over from the Bolt issue. Then there are other times that the unexpected wall power draw are not fully understood, such as OnStar comms with the mothership - and not wanting to sap range if plugged in and the car is awake doing things. The car also does more thermal management of things when plugged in and able to draw wall power.

Your other issue with the car charging now and delayed charging going away is likely due to how you plugged in. If you plug in and then unplug and replug (within a time window), the car will bypass the scheduled / charge-later setting and charge immediately. This is mentioned in the owners manual, and a way to force immediate charging without going into the settings. Has been this way on GM since the Volt. Sometimes you can also inadvertently trigger this, if you have some trouble inserting the charge cord.

This is all 'normal' for this car. What is abnormal with charging is that if the car sometimes forgets the home location and charge level. I don't think you have that somewhat common occurrence going on here, but just something to be aware of that sometimes you have to reset your home location, delete and re-enter scheduling, and re-set the charge target. Not often, but this is randomly reported - happens unexpectedly, and sometimes after a OTA or dealer update.