No power within 20 minutes

So I just got a 2013 Tundra Limited with 126,000 miles on it in late February. I love the truck. However, today I went to service a pool, turned the truck off, was out of it for about 20 minutes. When I went to leave, had no power at all. No ding, no dash lights, completely dead. The weird thing is, the voltmeter showed 0.7 volts with the cables connected, but then 7 and then 5 volts with the cables disconnected. My brother showed up a couple of hours later to give me a jump. After jumping, voltmeter showed about 12.6 volts with the engine running. I did not wait long to drive off, but when I did, I drove about 50 yards, thought I left the tailgate open, so put it in park and it cut off. Had to jump it again, which it immediately started. Drove to Autozone about 8 miles away with no issues. When I had them check the battery, it showed 0 volts even though it started right up. We then disconnected the cables and it showed 7 volts on his device while my voltmeter showed 12.6. He said that he could not check the alternator while his device was displaying charge battery. Now, when I was there to service the pool, I had the rear window rolled down. When the truck cut out the second time, the rear window was also down. On my way to Autozone, I rolled it up. I will check it out, but is it possible for a bare wire to completely drain a battery in 20 minutes if there is a short, or something touching when the window is down? That is my starting point of investigation, since that is the only thing that was different from every other day I have driven the truck.

 

Start with what could be the most obvious issue - the battery. How old is it? Pull it, throw it on a charger, see what happens. Battery should read 12.5v+ after it's charged and resting. 12-12.5v is weak, below 12 needs to be replaced. Often times, you will get a bad cell that will temporarily hold a charge until a load is placed on it (starter, headlights, etc) or bleeds off after 20 mins and the battery will read 9v. 7v usually says two dead cells.

Start with the battery and work your way out from there. The truck needs to be running to check the alternator, but the simply way is with a multimeter - should read ~ 14V. Less than 13.5 usually indicates a problem, or a battery problem so its important to have a battery that is known too be in good before looking at the alternator.

Once you've chased both of those down, if they are both good, look for a draw somewhere. Any aftermarket accessories? Any recent repair work or maintenance to the vehicle? Draws are difficult and time consuming to find, but you need a good battery to chase them.

I've replaced the battery twice on my 2013. Both times I felt like I got my moneys worth. Last year, the truck sounded a little weak on startup but started, even in sub freezing temps. But I got a phone call just before arriving at my destination, so I parked, shut the truck off except continued the call through the hands free system. After 10 mins, the speakers sounded really tinny and quiet, then the truck completely shut off. Dead battery.

 

Welcome from NY.

I would start with a new battery since you bought it used you really don't know how old it is.

 

Welcome from LA (Lower Alabama)!

I 2nd the replacement battery. It sounds like a dead cell or two.

 

https://youtu.be/B__DqK90IIc?si=gZqTM8GRHDeekmvv

 

If the battery proves to be ok, check the ground wires for corrosion.

 

So after being home for about an hour, the battery voltage had gone down from the 12.6 volts down to 12 volts, a bit later down to 11.8. I went to the zone and got another battery. When I pulled the old one out, it was from 11/23 so I am hoping just a crappy battery and not some short somewhere ruining batteries. With the new one in, while running, the voltmeter was reading 13.44 at an idle of about 1000. I guess I will check the voltage in the morning to see if there is a draw. Thank you everyone for the input.

 

Glad you made some progress on it.

 

As well the battery clamps.
I had issues with my 2005 having the thinnest layer of corrosion on the battery clamp.
You couldn't hardly see it, but this cleared it right up.

Welcome and good luck..

 

I would still check to see if you have any vampires drawing on the battery. Put an amp (current) meter in series with the positive terminal and the battery. You shouldn't see more than 100mA when the truck is off and no courtesy/door lights are on. If you do have a higher draw then you pull fuses until you find the vampire. If you're under 100mA you should be good to go. And make sure everything is cleaned (wire brushes ) and tight. Double check chassis ground for corrosion and clean if necessary. A used truck always needs new owner TLC to get her on the good foot.

The good news is your alternator apparently is working if you are getting 13+ v while running.