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I bought my truck used in the March of 2006. The battery died in October (21st) in it. I had to have it hauled to the dealer because it wouldn't even jump. I had the battery replaced (with a Truestart) and the charging system checked clean.

It seemed to run fine on Sunday when I last drove it (I walk to work) but it's dead now than a door nail. I've been keeping an eye on the guage and it was fine on Sunday. What would cause a drain that bad, other than a bad battery?
 

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I bought my truck used in the March of 2006. The battery died in October (21st) in it. I had to have it hauled to the dealer because it wouldn't even jump. I had the battery replaced (with a Truestart) and the charging system checked clean.

It seemed to run fine on Sunday when I last drove it (I walk to work) but it's dead now than a door nail. I've been keeping an eye on the guage and it was fine on Sunday. What would cause a drain that bad, other than a bad battery?
Interior light left on would do it. Also, any accessory that should be switched but isn't turning off would do it as well(like an aftermarket radio that was wired to constant +12V rather than switched). You bought the truck used, does it have any aftermarket stuff like a radio, amp., aftermarket lights, etc.?
 

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Discussion Starter #3
Interior light left on would do it. Also, any accessory that should be switched but isn't turning off would do it as well(like an aftermarket radio that was wired to constant +12V rather than switched). You bought the truck used, does it have any aftermarket stuff like a radio, amp., aftermarket lights, etc.?
As far as I know, there is no aftermarket anything and I don't think anything was on. Must be something I can't see off hand, I guess.
 

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It's not uncommon for a bad battery to ruin an alternator, and vice-a-versa. If your alternator is bad and not charging at 13.5+ volts, then that could be the reason. If it were charging, for example, at only 11.5 volts, then when you put a brand new (and fully charged) battery in it, it could easily take weeks or even months for the battery to get low enough so that it wouldn't start or the lack of charging finally burned the battery out prematurely.

I had this problem with my work truck, an F-250. It took me 2 years and three batteries to figure it out. After it sat for more then a few days, it would be dead. Otherwise it usually ran fine.

You said they checked out the electrical system, but are you sure that they actually did? I would take it down to them again, and watch them test the alternator. It's quite simple, they just hook up two wires and look at a readout screen that will indicate what voltage it's putting out.

Good luck. Let us know what you eventually figure out.
 

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if leaving dome lights on all night run your battery down you have a bad battery. They don't draw enough power to flatten a battery.
I'm with willy, have your alternator checked out.
 

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Discussion Starter #6
Thanks... I'm getting ready to have it towed. They supposedly checked my alternator last time.. but I'll have them look again. Thanks for the help.
 

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While you're at it check your cabling to the battery. A loose or bad connection can do the same thing. Check the ground wire connection to make sure it has good contact and replace them if they look questionable. New cables cost less than a tow, a lot less.
 

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Well.. they didn't find anything wrong again. They replaced the battery, checked the charging system and said that there was no draw on the battery when the truck was turned off.

He did say that I may not be driving it enough (letting the battery charge), that the battery could be being depleting because of the starter and I'm just not driving it enough (longer trips) to recharge the battery.
 

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Well.. they didn't find anything wrong again. They replaced the battery, checked the charging system and said that there was no draw on the battery when the truck was turned off.

He did say that I may not be driving it enough (letting the battery charge), that the battery could be being depleting because of the starter and I'm just not driving it enough (longer trips) to recharge the battery.
Any quality battery should last at least a few months when unused. The historic car club I belong to has a 37 Chevy firetruck with an Optima battery in it that we use for 4th of July parades. It gets driven once a year, at most twice. When it's parked, we unhook the battery. It'll sit an entire year, and then fire right up.

I still suspect an alternator that's not charging enough, but if you physically watched them test the alternator, then I suppose it's something else. Next time your battery needs replaced, try running an Optima. The Tundra takes Optima #34R.
 

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You should either go to another shop or test it yourself. Turn on the truck with headlights, ac with blower to max and stereo on then using a digital multimeter check the voltage to the battery. If you see anything less than 12.5v (which is weak) time to replace the alternator. I don't know if the tundra has the voltage regulator built into the alternator but if it doesn't then you'll need one of them as well. If it is separate then it should be checked along with the alternator.
 

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You should call your local auto parts stores and ask them if they carry the optima. The exide orbital is a clone of it so if you can't get an optima you might think about that one.
 

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If your driver's door isn't closed properly and you don't lock the doors, your cargo light (and/or interior) may stay on and drain your battery. Don't ask me how I know.... :eek:
 

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did they check the amps? a lot of shops don't have the equipment
to check amps. amps are much more important than volts.
just so you know, an alternator can't charge at less than 12.6 volts.
goes againist the laws of physics. yspert
 

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They replaced the battery, checked the charging system and said that there was no draw on the battery when the truck was turned off.
There is going to be some draw, however minor. I would check this myself by placing an amp meter inline with the battery. Should be around 50ma or less. If it's higher, start pulling the fuses to see which system is draining the battery.
 

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True start is the Walmart brand battery I had 3 of them bad off the shelf before I went to a shop that sold interstate batteries. Napa gold would be better. Optima are agm batteries they do carry a premium price.
 
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