Battery problems -- theft deterrant system to blame?

My 1999 Toyota Camry has gone through a couple batteries now -- the first time I just figured it was about time, and the second time (only about 4 months later), I was suspicious but thought it might be accounted for by my poor driving habits (frequent short trips). The battery indeed had minimal charge, both times, when checked with a voltmeter; I replaced it a third time, and after a week, the battery was dead again.

Now I suspected the alternator, but when I jumped the car while measuring the voltage across the battery, the voltage steadily increased and plateaued over 12 V even after disconnected from the jumper car -- so it appeared to be functional. At this time, I noticed that the negative terminal on the battery had been loose, so I thought perhaps the poor connection had been preventing some charging in the days before it died. I let the car sit for about 4 hrs, and the voltage across the battery was again down to about 2V (fatally low, I'm told, for a battery). Given the supposedly "catastrophically" low charge across the battery before I jumped and recharged it, I'm unsure whether or not the speed with which it discharged is any indication of a "drain" on the battery or whether it's now just inherently unable to hold a charge.

I have a hunch that it should have been able to hold its charge a lot longer, and that the discharge indicates something is draining, possibly the theft deterrant system. So two questions:

1) Has anyone heard of problems with faulty theft deterrant devices draining batteries? I've only owned the car since August, so I'd say it's conceivable that this problem might arise now despite several months of ownership during which I was in fact using the theft deterrant system without noticeable problems.

2) Furthermore, does anyone know how to specifically disconnect the theft deterrant system on a 1999 Camry short of pulling out fuses?

Thanks!

Reply to
chris.mcgraw
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With the engine running at high idle your voltage across the battery should be at or over 14 volts, it's usually around 14.5 volts but I'd sure look askance if was much less than 14 volts.

What I'd do is jump it...then charge the damned thing well, maybe a good long spin up the highway, maybe a couple hours (during the day) then get someone to hold the engine at high idle (maybe 1500 RPM) and check the voltage across the battery, you should see at least 13.5 volts, more likely you'll see over 14.

Now if all seems well, shut it down, make sure everything is off, no lights on etc, take either battery terminal off it's post and check the current between the post and the terminal that you removed. If you're not familiar with an ammeter you can use a small 12 volt bulb instead. (like one you'd find in the glovebox etc). It shouldn't light. Remember that you'll lose the radio presets etc when you disconnect the battery. Good luck (I have a

2000 Corolla which has never had the battery changed - nor anything else either!)
Reply to
Gord Beaman

FYI, if you discharge a normal battery too deeply and leave it in a discharged state, it will lose its ability to hold a charge.

The alternator should be putting out somewhere in the vicinity of 14 volts if the battery is deeply discharged and output will gradually drop as the battery reaches full charge. Assuming that the battery clamps and alternator connections are tight, have the charging system checked at the place you got the battery if it is not putting out at least 14 volts on a discharged battery.

There is nothing in the factory theft deterrent device that can cause the battery to drain in 4 hours unless it is constantly blowing the horn and flashing the lights, and even then it might last longer. I have never heard of the factory security system causing that kind of drain. That is a pretty quick drain and if you are purchasing cheap batteries, it is just possible that you are getting bad batteries You can hook up an ammeter and measure the drain on the battery. Normal parasitic drain should be measured in milliamps. If you are getting more, you can pull fuses one at a time until the drain stops. Things to check first:

1 - aftermarket audio system if so equipped 2 - aftermarket security system if so equipped 3 - aftermarket power socket and accessories hooked up to the power socket 4 - aftermarket lights like fog lights, "mood lights" if so equipped 5 - stuck power door lock solenoid 6 - light on somewhere, like glove box or trunk

Sorry, I've never tried disconnecting the theft deterrent system on a 99 Camry.

Reply to
Ray O

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