Electrical: Battery is draining Options

[hi4head]

OK - I got the opossum taken care of and have figured out the windshield washer system, now time for a real problem.

Since the car has been sitting for the past eight years without a battery, I put a fresh battery in about 1-1/2 weeks ago. Friday I noticed that the battery was about dead. I figured that maybe we'd left the cabin light on or something and didn't give it much thought, just hooked up my trickle charger and let the battery recharge.

Yesterday it was about dead again and I started growing suspicious. I figured something was either making contact and it shouldn't be, or I had a bad battery.

I've disconnected that battery and hooked my multimeter up to the positive strap and the ground strap. I would expect that it should show an open circuit, but no, it shows that current can be passing. When I flip the cabin light switch on, it shows no resistance (as expected).

I've left the meter connected and started going through various visible connections and points in the system. (i.e. disconnected each of the connections on the relay board in the engine compartment, removed each of the fuses there and on the fuse board under the steering wheel, disconnected the clock) Nothing that I've done has changed the resistance level shown on the meter.

Anyone have any ideas on how to procede?

Thanks,

Chris

[Hoss]

Chris,

There are plenty of folks on this board who are much more familiar with 914 electrical systems, but I will offer some thoughts in order to understand what you have posted.

1. Battery condition - You mentioned that you have a new battery, and that you fully recharged it. Subsequently it was dead within a short amount of time. I would suspect an internal short or defective battery. A fully charged and new battery would not be drained down that low unless you had a large drain. An operative clock will not pull enough current in that short amount of time to fully drain a battery.

2. Current test - You said that you measured the current between the positive strap and the ground strap. If you are actually trying to measure the circuit current, you should have the DVM in serial. Placing the DVM (set on current settings) from the negative post on one lead and then the other lead on the negative strap will give you the current flow. It is unclear what you think you are measuring based on what you posted.

3. Battery internal resistance - I would check the internal resistance with the battery completely disconnected from the car and compare it to the specifications to help determine if it is bad.

4. Resistance level - I am not sure where you are measuring the resistance, and it probably will not tell you much information. If you determine that the battery is indeed good, then measuring current draw step by step as you tried makes sense to see if you can isolate where the draw is coming from. If you are hunting a fairly significant draw, you could do a quick and dirty by checking the voltage across the battery as well. There will be a voltage drop across the battery that you may be able to see. For example, instead of a baseline 12.75 volts without a load, it might be 12. 5 volts hooked up with something on the circuit drawing a load.

Good luck with the efforts to isolate the problem. I would first suspect the battery since it is new, and there are times a new battery is in fact bad. Assuming you have a good and fully charged battery, conduct the current test with the DVM in series to see what the current draw is originating.

Cheers.