Battery problem

[jornvango]

2013 Chevy Tahoe with 120K miles. Battery was last replaced Jan '17.

For the past 8 months, especially after a cold night or when we haven't driven the car for a day or two, the car shows low battery level indicator and has trouble starting (but hasn't left us stranded ... yet).

A few months ago my wife left an interior light on which drained the battery enough so the car didn't start. We charged it by hooking up our solar panel to recharge it.

A few days ago after a very cold night (10 F), the battery was so low (as indicated by the gage on the dash) that it barely started.

Yesterday morning, after overnight temps around 35 F, again the battery level gage showed low and the car barely started.

We have been to Autozone / O'Reilly's multiple times and every time the battery, alternator and starter tested 'good'.

This morning I plugged a volt meter into the car. It again had trouble starting. Here are the readouts:

1. Before car start in the morning 12.0 V
2. During start 10.8 V
3. Started the car and during driving 14.7V
4. Stopped the car after driving 30 mins 12.5V
5. After 1 hour of not running 12.2 V

Any idea what is going on? It reallyfeels like one of these mornings the car is not going to start which will be a problem if we're camping off grid.

Thanks!

[jornvango]

Lynnmor wrote:
Family member has a Tahoe that is a few years older that had a similar problem. Turned out to be in the instrument panel so a complete replacement was the fix.

Would a 'complete replacement' mean replacing the Tahoe, its instrument panel or just the battery? :@

[Lynnmor]

Family member has a Tahoe that is a few years older that had a similar problem. Turned out to be in the instrument panel so a complete replacement was the fix.

[Krusty]

You should get a battery charger and charge the battery up fully. Also, if the battery and charging system test good, perhaps there is something drawing the battery down overnight.

[Roger10378]

What happens if you let the battery charge longer? 30 mins of driving is not enough to bring a battery up from 12.0V to fully charged. A fully charged battery is 12.7V.