Battery dead after three days of not starting.

I have tried to search and see if anyone else has had this but haven't found much. If I don't start my truck for a few days, ( my work has me traveling, usually two or three days) when I get back the truck might start but is sluggish. Then the next time I try it it's dead. Have taken it to dealership, which is about 30 minutes away. By this time the battery is recharge and they don't find anything.
Last time it happened I took them the dead battery and they checked it and said they didn't find anything and couldn't really check it properly with the truck. Got them to give me new battery. Went on vacation for 12 days and get back and the battery is dead...

 

Get your alternator tested.
Could be a bad diode in it that is causing the drain.

Any place that tests them other than your dealer should work.

 

This would be very frustrating. Have you added any lighting, audio upgrade, or any thing electrical like USB ports? If so that is where you need start looking.

 

This. I had an alarm/remote start in my old 2002 Tundra that would kill a battery in 3 days. Removed the alarm/remote start and never had the problem again.

 

Do you have a digital volt meter?
If so you we can probably help you rule out a few things.

If not, there are a few things you can check yourself. Nothing complicated, just looking for poor connections and, or, corrosion on a couple battery wires.

First thing I would check would be your batteries voltage after the truck has been running for a bit or after being charged with a separate charger. Make a note of the voltage right after its had a charge. Then turn your headlights and high beams on for a couple minutes, then after you turn them off get another measurement. Wait about 10 minutes and check one last time.

Basically you are taking a reading while the batt has its surface charge just to make sure it is at least in the 12.7 to 13 volt range.

Turning the head lights on will burn off the surface charge and some, but the voltage will still fluctuate up or down for a bit and that's what we want to figure out. Will the batt rebound back to an acceptable voltage, or is going to fall off fast. So that the second reading to take note of.

And after about 10-25 minutes the battery should be at its resting voltage. 12.4 and up is satisfactory. 12.4 is a little iffy but can start a vehicle in most cases just fine. 12.6-12.7 is an ideal resting voltage for a flooded cell batt, aka, a typical car batt.

Agm batteries can vary by brand. Optima red tops rest at 13.2 ish volts.

If you don't have a multimeter, grab a few wrenches and clean your battery lugs and wire terminals. And they should be tight and not have any play in them.

Then check the end of the negative wire that is screwed to the truck body right their next to where the battery sits. There's a few others that you can check but it gonna be that negative wire mentioned not grounding out very good.

That's where I would start. Actually I would clean and tighten the wires and lugs first. Cause that easy and it is more often than not the problem.

 

I have added an amp and aftermarket radio. According to dealership this is common for a Tundra and other Toyota models. Suggested getting a battery tender and 300 foot extension cord to bug in while I'm away on work.

 

YOU SIMPLY HAVE GOT TO BE SHITTING ME.

Read my sig line. Good grief Charlie Brown.

 

I wonder if it could be as simple as the remote wire for your amp not connected properly or the amp not shutting off?

Try pulling the amp fuse next time it’s going to sit. Or the radio fuse to rule out either one. Since that’s the only thing you’ve done to the truck. A battery tender is a Band-Aid for something that shouldn’t happen in that short period of time. I know on my past vehicles if they sat for more than three weeks, sometimes they wouldn’t start. But a couple days shouldn’t be a problem at all.

 

I checked the battery, when it was dead. 12.78. Then with a load it dropped to 8.something. With it charged it was 13.04. The dealership checked said it was 650 out of 700 something which they said was good.
I have checked to see how many amps it's pulling with door locked and everything off. 0.02 amps.
Plan to take it back next week to leave there a few days so they can monitor it.

 

No. This is not common. Most likely an install error for the stereo equipment.

 

I installed the radio. Same system I had on my Jeep wrangler, never had any battery issues with it. Used the wire harness from Crutchfield so everything was plug n play.

 

Im almost positive that 12.7v dropping to 8v with a load is well beyond the bad battery threshold. 10 volts is considered a dead battery and on my old load tester anything that tested under that failed if my memory is correct.

Id see if the autoparts store get the same results as the dealer.

Wait, is it the oem battery still? If so, there are a ton of ppl who have had bad experiences them.

 

I'd be tempted to punch whomever said that right in the Jimmy

 

Well yes and no. It is an OEM battery but I'm on my the second battery.

 

I think Tundras may have an issue with something (ECU, etc.) draining the battery too much. that combined with a cheap oem battery ...

My Tacoma battery lasted 8-9 years and at times I had left the car parked for a month or more and never an issue.

If I leave the Tundra parked for a week, the car starts fine but I get abs, Traction control and couple other warning lights and I have to restart the car to clear the faults. I posted here and was told this is due to a weak battery.