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Twice now my 2020 Ascent (1500 miles) has suffered a dead battery at the end of a weekend camping trip. This happened after having doors and lift gate open to load the car - but not for hours, more like 45-60 minutes, on and off.
Also, on the second occasion I started the car successfully 10 minutes before it failed.
The rear cargo light was also switched off on the second occasion.

One theory I have is that charging a device via the front dash USB ports -- while the car is turned off -- results in a dead battery and a non-start. On the second occasion, with the car turned off, I plugged a walkie talkie into the USB charge port for 3 minutes prior to the dead battery. And I believe had did the same with a GPS device on the first occasion that the battery died (4 weeks prior). Despite the car being turned off, the walkie talkie was actually charging on the second occasion. I can't remember if the GPS was charging on the first occasion.

Has anyone else linked USB charging to dead batteries after 2-3 days of the car not moving? Can a USB charge drain the battery voltage that quickly? Or is the OEM battery just weak sauce?
About to head on 1,600 mile road trip - and I'd like to know if I can rely on the battery as long as I don't charge USB devices while the car is off.
P.S. I was able to self-jump the Ascent on the second occasion using this portable jump starter (BEATIT G18 QDSP 2000Amp Peak 12V Portable Car Jump Starter): https://www.amazon.com/gp/product/B07FTG9PBK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
 

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2019 Ascent Touring (CWP)
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You may want to read the various threads here about battery drain...

Personally, I would not leave anything charging unless my vehicle is actually running, anyway.
 

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Discussion Starter #3
You may want to read the various threads here about battery drain...

Personally, I would not leave anything charging unless my vehicle is actually running, anyway.
Thanks. I did read the threads. I also experienced the rear gate beeping noise on the first occasion, along with the steering wheel lock - as some of those threads mentioned. During that dead battery occasion the rear gate would not open (now I store jumper cables and battery booster under the driver's seat). But I didn't see any mention of USB charging as a contributing factor - so I wanted to raise that potential factor.
 

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I know of no link between USB charging and battery issues. The Watt-hr capacity of phones and small tablets is a very small fraction of the Ascent battery has, so fully charging them from dead would only put a small dent in the battery. That's not to say it's not possible for some related electrical gremlin to cause a problem...but I'm not aware of any.
 

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Starting the car just briefly will drain the battery more than it can charge it, possibly contributing to it dying on that occasion.
 

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Starting the car just briefly will drain the battery more than it can charge it, possibly contributing to it dying on that occasion.
True, that's one of the reasons to replace the OEM battery, it has a poor reserve capacity.
 
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