Here's some background. The battery is the Optima Red Top Performance sealed with 925 cold cranking amps. Alternator is charging fine. When the car sits for a while, like say a month, I go to start it and it's dead. Is is possible the radio is draining the battery? The radio has a program memory so it can remember your stations. There's an itys, bitsy red light on the radio that remains on after you turn the car off. Once the battery is charged and you run the car around, it fires up for days, but let it sit for any length of time (more than two weeks) and nothing. Can something thats so minute be killing my battery or could there be another cause?

I can let my 72 240 sit for months and go out there and she starts like a charm with the factory Nissan battery.

Vicky

I found my map light drains the battery even though I didn't have it "plugged in," per se. Door switches could be actuating...hmm. Could be the radio, the clock, a lot of things. Any ideas?

Thanks gema

I think we'll try and un-hook the radio to see if that's the cause. It really is useless in that car because you can't even hold a conversation, let alone listen to some tunes, the engine is so loud:cry:

Vicky

Vicky,

I had the same problem.

Ran test to find the problem. No luck.

Bought a battery kill switch.

No more dead battery.

Originally posted by 2-4-T-Z-MAN

Vicky,

I had the same problem.

Ran test to find the problem. No luck.

Bought a battery kill switch.

No more dead battery.

That sounds like alot easier install than undoing the darn radio. Thanks 2-4-T-Z-MAN :classic:

Vicky

Does this car have an alarm or immobiliser? because that would drain teh battery also, so would the clock.

This was my phantom battery drain (the latest one, I mean). I had the map light actually disconnected from the ground wire (it broke loose and I haven't reconnected it yet). The switch would be pushed into the "on" position and my battery would drain. Even though the light was not illuminating...does this make ANY sense at all? 'Cause when I touched the ground back to it and made sure the switch was "off," no more battery drain. Silly Z.

Disconnect the + terminal from the battery and hook up a simple light type circuit tester, or just a simple 12v bulb. If it lights up, no matter how dimly with the key in the off position, then you have a current drain. If it doesn't you do not. It's that simple.

Now, to trace down WHERE the current drain is, simply hook up your bulb again, and go inside the car and start disconnecting likely candidates for the drain. Typically: the accessory relay (mounted on the kick panel on the 240); or the Glove Box Light. Those are the easiest to find and detect. When the light at the battery goes off when you've disconnected an item, that's the item that's causing the drain.

Memory keeping circuitry on radios or alarms is usually so low as to take literally months to drain a properly charged and in good condition battery.

2¢

Enrique Scanlon

Enrique's method is really the easiest way to find the drain. The battery cutout switch may be the quickest way to solve the problem. Mr. Camouflage's comment about the immobilizer is quite correct. When my homemade immobilizer red LED is "off",the main solenoid in the circuit is constantly energized and uses a substantial amount of energy, and will drain the battery within a few days. Sounds counterintuitive, but when the light is "on", the main solenoid in the circuit is not energized, with the only energy drain being the LED, which wouldn't drain the battery for many weeks. Thus, whenever I turn the key off, I turn the unit on. Victor.

Thanks for all the info guys. Scott is going to try Enriques method this week and see what the cause is. There is no immobilizer on the car so that's not it. Again thanks for all the input.

Vicky

On a well maintained car you probably just have a short in a wire.

i had similar problems, took to auto electic, they said my alternator was draining the power due to faulty part within alternator. (5 min job to test). paid roughly $150 to fix.

But turns out my wiring from by alternator was draining the power. get this checked before refurbishing alternator.

ps. my 260z has had alternator replaced with internal regulator version. a few others i know have had similar problem with their Z's