My 2011 Silverado's (124,000 miles) battery was changed 27 May after the old one lasted almost 6 years. I bought O'Reilly's best battery (Platinum series). End of June after 7 days sitting in the garage without being run, the battery was dead. I took it back to O'Reilly's and they tested it, and battery was dead, and the charging system was working. They gave me a new battery. Since then, the battery has gone dead twice, each after a 6- or 7-day period. I am guessing the truck is causing the problem. I do not see any interior lights on that would drain it. Scared to take to dealership or local shop until i do some research on this problem. Anybody go thru this on their vehicle where it was not a light on. Is Computer powering something that I can't see or hear?

 

Something is drawing excessive current, with a voltmeter on the battery, disconnect i.e. pull indidvidual fuse's see if/when the volt meter stops showing the voltage drop, that's it. Excess current in in the mili-amp range.

 

Thanks for the idea of pulling the fuses. I have a clamp-on meter arriving tomorrow that will read DC amps. Thanks again

 

You really just need a voltmeter.