'97 Battery dying

[Jeep & GMC]

My truck is a '97 chevy 5.7 vortech. When I leave it for a couple days it's battery is drained till it won't crank. Today there was no clock or anything, completely dead. It had been jumped and driven 4 days before. The battery had been stored on a shelf for weeks since having a charge and worked great, so I think the truck is draining it somewhere. Any suggestions on what to check? Thanks

[ed2552]

have the battery load tested at NAPA or wherever, they discharge no matter where they sit, the wive's tale that concrete discharges it faster is just that, a wive's tale, or myth, that is not true. Make sure it is not the battery b4 starting ANYTHING else

[truckdude239]

if the dieos in the alt are bad it will charge when running but will drain back off the battery when not running they are a one way check valve for the charging system

[89 crew]

Have the alternator tested. I'm betting it has a problem.

[Jeep & GMC]

Originally Posted by truckdude239

if the diodes in the alt are bad it will charge when running but will drain back off the battery when not running they are a one way check valve for the charging system

I didn't see your post last time but that sounds suspiciously like my problem.
Last night I got it running and disconected the positive from the battery to test the alternator and it continued running fine, and whenever I touched the terminal with the cable the idle slowed like the alternator was working harder. But the diodes sound alot like my problem. Can just the diodes be replaced? Or does the whole alternator need to be replaced. Thanks alot for the help.

[89 crew]

They can be if you know how to open the alt and put it back together right. If you have never done that before, I'd recommend replacement.

[Jeep & GMC]

It's had this problem with two different batteries, At first it was the Bosch that came in it, so I changed it out for an Interstate that was laying around. The Interstate started the truck fine, but then went dead after being in the truck for a few days. I will try to have it tested though.

Once it's been jumped, and driven for a few minutes, it can restart itself, so it would seem to me that its not the alternator, but I will look into that also. Thanks for the replies guys.

[truckdude239]

Originally Posted by Jeep & GMC

I didn't see your post last time but that sounds suspiciously like my problem.
Last night I got it running and disconected the positive from the battery to test the alternator and it continued running fine, and whenever I touched the terminal with the cable the idle slowed like the alternator was working harder. But the diodes sound alot like my problem. Can just the diodes be replaced? Or does the whole alternator need to be replaced. Thanks alot for the help.

NEVER EVER remove the batery cables with the engine running it can casue a voltage spike that will burn out your computer.

you can replace the diodes but its not easy if you have never done it normally a good replacement with a lifetime warranty is easier and cheaper

[ChevLoRay]

I'd get the batteries and the alternator tested. You know how to swap batteries, so that ain't gonna be a problem. There's two bolts that affect the alternator. Pull it off and take it in for testing, OR find someone who has a portable testing device and let them hook it up. My experience is those portable testers (hand-held) don't always get used correctly and they go bad. O'Reilly's, AutoZone, etc., usually have an alternator testing bench.

[jgrh64]

while it's not running disconnect the neg terminal and wire a regular turn signal bulb ( 1156) in line between the cable and the battery terminal - if it glows brightly you have a major drain . pull the fuses 1 by 1 till it goes out or gets very dim - that is the circuit that is draining the battery you will have to troubleshoot the circuit or take it to a good electrical service place

[Jeep & GMC]

I've been working out of town so it's taking me a while to get all this stuff done. Last weekend my dad took the interstate battery to the interstate dealer who tested it and said all of the cells tested the same, but they were all less than perfect so he gave me a blem battery (which by the way is an awsome deal). It was in the truck from monday night to friday night when I got home and it started fine. I'm hoping that the problem is solved, but I will keep watcing it. Thanks for all the help you have all donated.

[truckdude239]

any updates did youg et it fixed?

[Jeep & GMC]

Yeah, I still haven't had any trouble since I installed the new battery, it must have just been coincidence that I had two bad batteries. I definetly recomend these interstate blemished bateries. Thanks for all the advice guys.