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A Honda that kills batteries

I have a 1996 Honda Accord EX that has killed four batteries in the past two years. I’ve investigated the alternator, and it is not the problem. If I go for more than a week without starting it, the battery dies. After several rounds of this, the battery quits holding a charge. I don’t use the car often, but I never go for more than two or three weeks without trying to start it.



Any ideas?



Steve

Two or three weeks of inactivity should not hurt the battery. I have a '97 Accord that routinely sits that long and the battery is fine.

If the alternator has been tested and is good, there has to be something draining the battery. Is the trunk light on all the time, perhaps? Have you installed any non-factory equipment such as an alarm system or a stereo?

A shop that specializes in automotive electric/electronic systems may be able to track down the current drain. Or you could start pulling fuses one at a time until you find the circuit that is causing the problem.

If nothing else works, a Battery Tender will keep the battery properly charged while the car sits unused. Not a charger, a Battery Tender. They start at about $40. I use one on my battery over the winter, when the car may sit for 6 or 8 weeks at a time, and it works great.

Obviously a current drain… you need an ammeter to measure the drain (put between the battery positive and the battery positive clamp) and pull fuses until the meter reads 0.

I had a misadjusted trunk light switch that would allow the light to stay on. That’s a quick fix. If it’s worn insulation allowing a short it might be harder to find and fix.

Thanks

I got the car from my mom, who did have an anti-theft system installed. I’ll check that out. If it’s not that, then I’ll take it to a automotive electronic specialist. It’s not the trunk light. I’ve checked that.

Steve

If the anti-theft system controls the ignition, that is a bad idea. An anti-theft system is safest (for the engine computer, especially) if it acts to prevent starter operation, or some other system…not the ignition system.
After the engine gets hot, and you shut off the engine, the radiator fan will (often) come on and run a few minuets. Sometimes, when there is a problem with the radiator relay (or, its control), the radiator fan will come on, again, when it needn’t.
After the engine is shut off, go back a half hour, an hour, and later, and listen for the radiator fan. If you hear it running, change the radiator fan relay.
If that doesn’t cure it, the engine coolant temperature sensor may be sending a “coolant too hot” signal to the engine computer (which would then turn on the radiator fan to cool the engine).
At a different time, after you shut off the engine, and the radiator fan has run its course, do some amp draw tests:
The only things still drawing power are: the radio/cd player, the ECM (engine computer) memory, the clock, and ? Pull all the other fuses.
After a half hour, start your amperage draw tests. Put your multimeter probes into a fuse socket, or you can use this little amp meter: http://www.toolsource.com/fuse-buddy-tester-blade-p-98602.html (which I prefer).
Everything that’s not running memory, or that anti-theft should be at, or near zero amps. When you test the fuse socket, you are testing the circuit that that fuse serves. If you check a fuse socket and see an amperage, that circuit may have a problem (short, etc.)

Check your glove box light, if you have a glow around the glove box at night, that could be the problem. This vintage Honda Accords can have that problem, especially if the glove box is loaded with junk.

One more thing, is there anything that doesn’t work, like the door locks or power window. This vintage also has a history with the power door lock module. A quick check on this would be to drive down the road and hit the power lock button to lock the doors. If it keeps cycling, then that module is defective. It tends to start pulling the locks very late at night or early in the morning when its coolest.