My 97 T4R SR5 3.4 is having issues. Ive had the battery, alternator and starter tested. First 2 are less than a year old and tested perfect. Just rebuilt the contacts in the starter 3 months ago and it tested fine too. Its been a week since this started and i have had to charge the battery every night. Its draining by 50% on 10-15 mile trips so its a pretty significant drain. I have not added anything new electrically to the system in years. I do have an amp (750 watts) but its been in the truck for 4 years and works fine too. Any ideas????

I had a volvo plague me for months before I got my runnah...tested the battery at least 3 times at 3 different places and all said was good...Finally took it to one shop and said it was good just not fully charged and would hook it up to the charger since I wasnt in a hurry...As soon as they hooked it up, that sulpher smell and the thought of an exploding battery quickly prompted them to unhook it and tell me I had a bad battery...I believed them for some odd reason (haha) and bought a new one...fixed with no other problems till I sold it...

I will put my money (or warranty) on a new battery.

If it's draining while you're driving either the alternator is truly bad, or one of the connections between the alternator and battery are bad. I'd start by taking the wiring of at the alternator and the battery first to make sure there is no corrosion on the undersides that would be causing charging problems.

Ok Guys..... exchanged my battery under warranty yesterday and unfortunately still have the drain. Drove 12 miles and it drained by 30%. This sucks. May give in and take it to the dealer.

I agree with Big John, it has to be either your alternator is not charging or the charge is not getting to the battery. You should have 14 volts at the battery terminals when the engine is running.

this amount of drain seems excessive. You should be able to test things out with a voltmeter or take it somewhere and get the alternator tested.

How are you able to tell it was 20%, 40% 60% drained ?

Based on what you have said I would try the following:
Charge the battery fully at 5pm. Check it out the next morning. If everything is fine then it isn't draining overnight.

You said it was draining while being driven.
Check:
1) the voltage is at 14.4 when running, as opposed to 12v turned off.
2) if batt is draining while driving and the alternator (or component of) has failed, then you might be draining the battery by using it up while driving (eg spark plugs, lights and radio) to power car's electrical components.

Not very technical explanation but hope it helps.

Hey Brian I was using a battery charger to tell how much drain. I doubt its 100% accurate but its all I have to judge it by. I also am convinced its the alternator, I am going to have it tested again tomorrow. Anybody think I need a high output alternator? As I said before it only has the after market amp and i never had a problem until now.

I had a serious battery drain and believe it was the CAP in my car audio system. What was happening was a slow drain that killed my battery every 4-6 months. After it killed an $150 optima battery I decided to start looking for the drain. The only thing that solved it was replacing my 3 yr old Tsunami CAP with the R.F. If the issue comes back again I am going to install a circuit breaker and kill it when I leave the car.

Last summer I replaced the CAP and the issue seems to have gone away although I have no solid proof other than the fact that battery isn't dead.

I am running a pretty decent sound system and still have the stock alternator. I used to have an issue with the lights dimming but the CAP fixed that.

97 4Runner Limited 4x4 @ 196k

Sound System @ > 1000 W RMS

* Alpine V-12 - 4x100 W RMS
&
* MTX Class-D mono amp - 650 W RMS
Powering:
- Two 12" MTX subs
- Front: 6.5" component Infinity Kappas
- Rear: 6x9" Infinity Kappas
- 1F Rockford Fosgate CAP

I have yet to need a new alternator and I have been running this setup for ~ 5 years.

Its ridiculous to try to diagnose an electrical problem with out a volt meter. They don't cost much.
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Like stated above you should have between 13.5 and 14.5 volts at the battery with the engine running. After you turn the car off the battery will have a surface charge, turn on the headlights for 30 seconds to remove the surface charge. Turn the lights off and then recheck the voltage. 12.6 is fully charged, 12.2 and below means your battery needs to be replaced.

To check for a voltage drain put one volt meter lead on the battery negative and the other one the ground wire on the body or the engine. You should get 0.00 or 0.02 or less. This tells you how much voltage is traveling through the wire. If you have a voltage leak there, start pulling fuses until you find the circuit which has the drain. I would start by unhooking your amp and see if that changes anything.