Battery Killer

just wondering if anyone has encountered a problem with repeat dead batteries. The original battery lasted a solid five years, then one morning woke to a dead truck. Quick trip to the truck hospital, standard transplant procedure, and she was rolling in no time. Till I go out of town, and within six months, she had killed two new batteries - dead, not just drained. Upgraded to a more powerful model and this one just gets drained after a week of no use. Took her in to my local shop, they spent a day checking all the relays but no luck locating the drain on the battery when the truck sits idle. Anyone got any ideas what's up?

 

Your alternator is dead most likely roll into any autoparts store and they can check it for you. Your truck most likely isnt charging the battery it is just using all the battery to run everything on the truck not the alternator

 

do you have a multitester?

 

There is more to the alternator than it just producing power when it is turning. You also have to make sure that it isn't shorted out. It is possible for the alternator to be charging the battery and also draining it when not running.

The alternator seems to be the most likely culprit, however, it may be necessary to test the entire truck for continuity (shorts).

Also; if there is no apparent problem, maybe try a different BRAND of battery, or a different store. A lot of batteries are "set up" by the store itself. If the store you are going to is a bunch of total fools, they could be setting the batteries up wrong and they could all be dying like this.

 

You mention they die after periods of no use. Has anybody checked how many milliamps of parasitic draw are present when the vehicle is just sitting there?

Alternator should also be tested.

 

Quite possibly the alternator. Mine went out a few years ago but was still under warranty....replaced that along with a new battery and no issues after that.

 

thanks ya'll, and yes, have already tested the alternator, each time the battery went dead and at the last recharge. but will check out if there's any draw when the truck is off. With my limited knowledge of the hi-tech systems, I was just wondering if there was some reset requirement after the electrical system experiences a comlete power loss.

 

How many miles on the truck?

 

Do you own a digital multimeter?

 

i have this problem. not with the taco but with my TL. if i leave it for 3 days, it'll die. if i know i will not be using it for more than 3 days, i would remote start it at 2 day the most to let it run a bit to charge the battery.

 

the way i see it..we cant take a guess from way over here.

you will need to post up some numbers you read off a multitester..so our guesses can be..better guesses.

i would love to know the voltage at the battery at idle.

 

I would also like to know if you leave your headlights on all the time. I know they are supposed to shut off when you open the door, but I've seen two Tacomas that, if even only once, don't.

 

Do you have any modifications to the truck? Install a new stereo or lights recently?

 

I agree with those above who think you have a draw from something. Batteries typically hold their charge for 6 months or better with out driving, and even then we are talking about a year for a new one to go down enough not to start.

Find a buddy with an amp meter. You need to know if you are drawing any current, and if so how much. If I get the chance I'll let you know what a healthy system draws.

 

To add clarity, here's some more data: My truck is just over the 97K mile mark and still running great!!! I don't have a multi-meter, but know a couple of guys in my riding group that carry those around, will get with them and do a check. Learned from experience in the first couple years of ownership, the truck has auto-shut-off for the lights (inside & out). No new stereo or lights, but had the speakers replaced about over a year ago... can't see how speakers would draw on the system when not in use, but will have those points checked out too. Thanks for the input.

 

Your truck will draw some power from the battery when the truck is off and the key is removed to keep things like the computer, clock, and alarm system active. But all this combined should draw less than half an amp. When you check the system, make sure everything is off and the key is not in the ignition. If you are drawing more than half an amp, you probably have a short in the electrical system somewhere. I can tell you that your speakers won't be an issue because they are a load device. They can only operate if the amplifier (JBL behind the back seat or the dash unit) is sending them a signal. If you had the amplifier replaced that would be a good place to start. Hope this helps your troubleshooting and that you get your truck up to 100% again soon.

 

+1 if it is not the battery. Had this issue on my old integra after installing aftermarket stereo and alarm. The draw when the key was out would drain the battery if left for more than a couple days.

 

So...how does one SET UP a battery or even better how does one SET UP a battery wrong?

 

If a battery is completely flat, it is possible to hook the charger leads up backwards and reverse the polarity of the battery.

 

check the ac compressor relay