Dying Battery or Phantom Drain

I am experiencing a frustrating issue with my car. About a month or so ago, it wasn't driven for 4 or 5 weeks. During that time, the battery on the car died completely. Wouldn't turn over, wouldn't have enough juice to turn on any lights, interior or exterior. So I charged my battery with a battery charger. Now, unless the car is driven regularly (2-4 times a week) the car's battery won't have enough juice to start the car.

My question is this: is this more likely to be the symptoms of a battery nearing the end of it's lifecycle? Or, is there some component in the system that is draining power faster than it should? It is worth noting that I have installed Toby's remote lock/unlock system. It was installed by me, and I am nowhere near a professional electrician or mechanic.

If it is the battery, should I consider replacing the battery? Which brands have you had success with or are happy with?

If it is a phantom drain, what is the best way to go about discovering the culprit on our cars?

Any help is greatly appreciated -- it's getting old having to charge the battery every week or so.

As a test, just leave it disconnected to see if it is a drain...

If you get a full charge into the battery and it won't start after a week then you may have a curtisy light not shutting off or the battery is shot. Pull the #12 fuse and leave it out. See if that cures your problem.

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Originally Posted by Bitsyncmaster

If you get a full charge into the battery and it won't start after a week then you may have a curtisy light not shutting off or the battery is shot. Pull the #12 fuse and leave it out. See if that cures your problem.

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If it is the courtesy light switch your simple fix (at least it was for me) was to simply install a shim on the door to get the plunger to fully depress when the door is closed. I had the same issue, battery drained only after a few days. Noticed when I drove the car at night the interior light would blink, pushing on the door made it stay on. I think it was just at that point to make contact and drain the battery.

Just as a point of reference - Last summer I disconnected my battery and put my car away for 2 months. To my surprise the car fired right up as soon as I connected my battery

I don't think it would have started if the battery was connected.

If the battery is over 5 years old, replace it. If it is younger have it fully charged and load-tested. To reduce the standby drain install a master switch. You can also check to make sure the radio is hooked up correctly, the cigarette lighter is not stuck, and upgrade or disconnect the door lock module. Make sure when the doors are closed the courtesy lights are all off. Add rubber tips to the plunger switches if they are missing.
David Teitelbaum

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Originally Posted by orbitron3000

If it is a phantom drain, what is the best way to go about discovering the culprit on our cars?

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If leaving it disconnected works, then it's likely some parasitic draw. If you have an amp meter handy, wire it in series with the battery and see how many milliamps are being drawn. Typical parasitic draw on a car with everything off is 30-50mA. If you're getting a lot more, that's likely causing your drain. To find the cause, pull each fuse and use the meter to connect the two terminals in the fuse box to measure how many milliamps each circuit is using and see which is the culprit. Let us know if you need more explanation.

A few years ago, all of a sudden, my battery would drain within a week, so that my weekend drives would start with a battery jump.

Soon thereafter I traced the leak to my radio's standby current requirements (for preset stations/options) having gone haywire. I fixed that and I can now start the car up after 3 weeks w/o use (which was a record for me in not using the car), battery plugged in.

You can easily diagnose the source of the leak with a multimeter that measures DC current (most do). Here's how:
1. Open fuse access panel.
2. Disconnect (or tape off) the door plunger switch, of the door that will be opened during this test.
3. Disconnect the battery ground.
4. Set your multimeter to DC Amps
5. Hook the meter between the battery and the cable you removed from the battery (big wire clips work well here).
6. Check reading.

That reading with the car off is your standby current draw. It should be well under 50 mA. The draws on standby would be: Radio, Clock, Keyless entry (if you have one), door locks.

If you have a high current draw, then the next step is to try to isolate it's location.

7. Keeping the same set up from above, pull one fuse at a time, check reading, put fuse back in.

Once you find a fuse that drops the standby current the greatest, now you have isolated which circuit to follow. That is how I traced it to the radio, and corrected the current leak.

Thanks everyone for the responses! This morning I disconnected the positive terminal from the battery and will see if the battery drains all by its lonesome.

If it turns out to be a phantom draw, then is it necessary to disconnect the ground (negative) terminal? Or can I disconnect the positive and wire in the multimeter from there?

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Originally Posted by orbitron3000

....is it necessary to disconnect the ground (negative) terminal? Or can I disconnect the positive and wire in the multimeter from there?

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lol. I've seen raging forum debates on this, but I generally follow the recommendations to remove the ground cable from the battery. Check this reference for um, well, reference:

"...always remove the battery's ground clamp before loosening the positive. If you remove the negative clamp and inadvertently complete a circuit to ground, there will be no current flow because the ground clamp is already grounded. Subsequent shorting of the positive terminal to ground will then produce no current flow because the current has no return path to the negative post. And, of course, always reconnect the ground last."
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