Battery dies in accessory mode

Even if you stop using accessory mode to kill it, and even if it starts reasonably reliably, there is the "my truck is losing its mind" problem. Radio forgets settings, "tank MPG" resets mysteriously, ... all symptoms of the battery seeming to "disappear and reappear during the night" even if it seems to be there most of the time.

 

Thats exactly how my OEM battery died too (found out after playing the radio for not quite an hour while cleaning the interior). Same thing as mentioned with the MPG monitors resetting too.
×2 on Costco. Their batteries are pretty good, especially for the price. No Costco card? Walmart's Everstart brand is a good second choice value if you don't have unusual demands such as offroad winching/running a camp refrigerator, etc.

 

Just grab whatever standard middle-of-the-road Group 24F battery is at your local auto parts store. It should run you around 200 bucks after tax.

 

Sometimes we just "need to jump ourselves"...

 

https://www.ebay.com/itm/2565102914...HlWiW87L/HRiMcHZciaDAefanA==|tkp:BFBM_OOJn61k

 

I would say that turning accessory mode on for 10m and an observing a subsequent dead battery is the very definition of a failed battery capacity test. However, this is very strange. I’m surprised a battery that bad could start your truck when fresh. Do you have any heavy lifting aftermarket accessories that draw in accessory mode?