1988 Acura Legend Draining Battery

Get a test light and disconnect the negative battery cable now put the light between the cable and battery negative post is the light On? If so start removing fuses one at a time -the fuse that turns off the light is the trouble circuit. Then break out the electrical wiring diagram.

In the event you removed all the fuses and the light is still On disconnect the alternator batt. feed and the connector-if this one turns off the light-the alternator has bad diodes.

Or you can use an ammeter which is the preffered method to check for an excessive parastic drain

Thanks Ras,
I have one of those 'multi-meter' voltage meters. I set it to 50V and when I test the batt with the car off it reads between 12 & 13, which (I think) is good. But when I disconnect the -ve cable and put the VMeter between the cable and the -ve post it reads nothing. Actually it jumps backward below zero.

I put the VMeter on lower settings (like 10V or 2.5V), but still nothing. I even tried disconnecting the +ve cable (after reconnecting the -ve cable of course) and running the meter between the +ve cable and the +ve post, but still nothing.

What do you think?

Paul.

Disconnect the negative battery cable-put the VM on 50v scale-Now put VM black lead to the Neg. battery post and Red lead to the Neg.cable if you have battery voltage start removing fuses as stated earlier.

Thanks Ras,

The VM worked this time. But I pulled out every fuse, even the big ones that were screwed in, and disconnected the alternator and nothing made it drop to zero.

However, when I pulled out the big 70A "Battery" fuse the VM dropped from about 12.5 to about 11, does that mean anything?

If not, what would you recommend I try next?

And I forgot to say earlier that the alternator is about a year old.

Thanks,

Paul.

Disconnect the alternator connector and battery wire from it-do you still have battery voltage? Let me know.

Yeah, I disconnected the only two wires coming into the alternator. There was a small one on the side (near the top) that lead to the battery, and a combo plug at the back which lead to a large electronic cluster. Then I checked the battery voltage again and it was still about 12.5.

Also, just in case there was something up with the neg battery cable I also grounded the +ve pin of the VM on the engine block instead of the -ve terminal while checking voltage and that didn't change the reading.

What about the 70A fuse that made the reading drop from 12.5 to 11, is that significant?

Thanks again,

Paul.

But when I disconnect the -ve cable and put the VMeter between the cable and the -ve post it reads nothing. Okay try starting the vehicle and check the battery voltage you should atleast have 13.5 volts while engine is running

Ok Ras,

I started the car and checked the battery with the neg cable attached and also detached. The VM read 14 with the cable attached and 13 with it detached.

Then with the car still running (just for fun) I hooked the VM between the -ve battery post and the -ve cable (as you described in an earlier post) and the VM read zero. And remember when I do that with the car off, it reads between 12 and 13.

What do you think that means?

Paul.

You're good to go-14volts for me running your alternator is doing its job-so whay is it doing now. Maybe you might consider another battery.

Hi Raz,

Ok, we seem to have lost sight of the original question, so let's recap.

Something is draining power from the battery when the car is off. If I don't start the car for about 4 days the battery is dead, dead, dead. Once I recharge it everything is fine. The battery is brand new and the alternator is about 1 year old.

Per your advice, I hooked up a VMeter and pulled every fuse one by one, but none of them dropped the VM to zero. The only fuse that made any difference was a 70A 'battery' fuse which dropped the reading from 12.5 to 11.

Then I also checked the alternator.

What do you think I should check now?

Thanks,

Paul.

The only fuse that made any difference was a 70A 'battery' fuse which dropped the reading from 12.5 to 11.

Your meter does it have a milliamp scale-its normal to have a draw below 25milliamps due to the memories-radio/clock etc-

Do a battery case drain-put the meter neg. lead to the neg. post and red lead positive probe on top of battery-do you have battery voltage. If so you have a case drain that needs some serious cleaning with baking soda and water and also might need charging after the cleaning.

Hi Raz,

Not sure you are understaning my question, so let me try to explain it better...

I hooked up the Voltage Meter as you suggested and pulled each fuse separately as you suggested. There is a 70A fuse that is labelled "Battery". When I pulled that one the VM reading dropped from 12.5 to 11.

Is that normal? Or can that help me to figure out where the drain is coming from?

And I tested for case drain, there is none. Remember, the battery is brand new.

Thanks again,

Paul.

There is a 70A fuse that is labelled "Battery". When I pulled that one the VM reading dropped from 12.5 to 11.

Remove the fuse Check for power before the fuse-power should be present and not after-if power is present after-something is back feeding it.

The draw is still excessive-might want to check out that circuit origin and where it terminates. Also check the glove compartment/dome light/trunk light circuits-

Also use the amp scale of the meter and till me the amperage draw.