Electrical drain Options

[Tom73]

Another newbe question here. Just got the car Sunday. Put in a new battery last night. Everything seemed all right and all electrics worked just fine. Went out this evening and battery is dead.

So apparently I have a major battery drain. Is there any quirks in a 914 that would cause a drain in any specific location/fitting/outlet/etc? What is the best way to track down the drain? Any special tricks you all use?

tom...

[scruz914]

First question is what was the condition of the new battery? New batteries can sit on a shelf a while and loose some power. It is obvious that you do have a drain with everything off but the condition of the battery may have been low enough for that drain to wipe the battery out.

I am trying to think of what could drain a battery overnight without causing other problems. To drain a battery overnight must be a considerable load.

There are several approaches to trouble shooting an unwanted load. No matter which you will need a volt/ohm meter. I am thinking that you may want to pull all of the fuses and check the current (amps) with no fuses (should be zero, I think) and then add one fuse at a time. You will have to disconnect either the ground or positive battery connection (for this kind of test I don't think it matters) and connect your meter between the battery post and the clamp in the current (amp) mode.

As you add fuses you should see some kind of increase in current that will point you to the source of your problem. That is if you don't see a current reading with no fuses. If that is the case then it means you have a drain before the fuse panel.

Debugging that will require the patience of Sherlock Holmes, and a knowledge of the wiring diagram for your car. I'll leave that kind of investigation if you do not find the problem down stream of the fuse panel.

Good luck!

-Jeff

[Tom73]

Any other thoughts out there????

tom...

[sgomes]

I'm not an expert but I think I'm the only guy on this board that has 20 batteries in his car. <_<

First thing I would do is disconnect the battery from everything. Just yank the positive cable off the terminal. See if it goes dead overnight. You might have a battery that is internally shorted or sulfated.

Next, I would invest in an "amp clamp". Basically it's a meter or an attachment for your DVM that lets you just clamp around a wire to see how much current is flowing through it. They are less expensive than ANYTHING you might buy for this car. It's going to save you a HUGE amount of time though.

First, put it around the unswitched +12V going to the back of the fuse box. The current you're looking for is going to be very easy to see. Hell, I could sit here and list the top ten contenders but I'll let you have some fun.

My bet is on the battery itself.

[scruz914]

I like the 'amp clamp' idea. Easier than my suggestion with the same end result. Do pull the fuses though to isolate the drain.

-Jeff

[Tom73]

I like the 'amp clamp' idea.  Easier than my suggestion with the same end result.  Do pull the fuses though to isolate the drain.

-Jeff

My fuse cover is missing, so does anyone have a diagram as to what each fuse is for? It is a '71.

tom...

[Tom73]

Last night I went looking for an "Amp Clamp" but could not find anything. I did find them for AC only but nothing for DC. Check autoparts stores and hardwear stores, nothing for DC.

So any info on brands and who sells would be appreciated.

tom...

[sgomes]

http://us.fluke.com/usen/products/Fluke+32...ukeUnitedStates

That is just an example. When I get to work I'll find out what ones we use. They are a bit smaller and would be great for tight spaces.

[Tom73]

Always worries me when, under price, it just says "Call for Price" (IMG:style_emoticons/default/sad.gif)

[sgomes]

Ok, at work we have a bunch of Extech 380941's Cute little things. Looks like they might be pricey though.... I think an accessory clamp for your DVM would be cheaper. I've seen them for $60-70.