Battery Drain

Somethings up with my car. At first I figured it may have been the battery calling it quits (optima red top going to be 3 years old this March) but found out today that there is definately a drain somewhere in the car.

Charged the battery on the charger at work, went to put it in the car when I got home, but after hooking up the - terminal I put my meter in line on the + terminal and the + cable (No other accessories hooked to the battery) and the meter read 11.75 volts...meaning something is pulling approx 12volts from the battery when the igintion is off. Next problem is finding it.

It seemed to have started when I was swapping the computer chip and had the computer pulled down from its cradle in the passenger side underdash. Now it's back up with the stock chip in all secure. This was also the last thing I messed around with before it started getting cold. Since then it will be good for a day or 2 then dead battery.

I'll have time to mess with it on Tuesday, but untill then just hoping somone here can help me maybe narrow down my search. The only thing I can think of is while dropping down the passenger side underdash, maybe I did something to the neon tube that I have mounted there which is causing it to be the drain. I feel its highly unlikely for it to be anything with the computer since when it starts up and runs, it runs fine but who knows with my luck.

what kind of vehicle do you have?

Ok, there is basic information missing, What kind of car? Also what other aftermarket equiptment is installed?

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Certified Security Specialist
Always check info with a digital multimeter.
I promise to be good.
Tell Darwin I sent you.

I've been sick lately, sorry I won't be on much.

You may have a bad cell inside the battery.

88 Pontiac Grand Am

When I tested for draw with the DMM power cable for the audio 4 gauge,1 farad cap, Fog lights, and neon underbody weren't hooked up, so I can rule them out as a source of draw.

Other added on accessories left in the vehicle not recieving power directly off the battery: Underdash neons(my first suspect of the problem), DEI 550ESP alarm rem.start, PS2 (wired to switched power from column), NOS Sneaky Pete system (power from column), nitrous purge valve (power from Column), Audiovox 5.6" monitor (switched power from Radio harness).

Basically what I plan to do is one by one, disconnect each of these items (especially ones wired to constant power) test for draw on the battery and see what my results are. Liek I said, I was poking around the passenger side underdash, and very well could have done something to one of the neon tubes I have on the underdash pannel. Guess thats my starting point and working from there.

Sometimes new batteries can go bad. But I doubt it. Did you check to see if you left any dome lights on? I know it sounds stupid but it happens sometimes.

na, no dome lights were left on.

Now am I doing this right? Had to do it once before and it was a while ago, talking close to 10 years ago..... Disconnect a battery terminal and put the volt meter in line with that terminal on the battery and its coresponding cable If you have voltage it shows their is something on in the vehicle pulling current? Because when I do that I get the same voltage as just the battery alone reads.

Also did this on another vehicle and had the same results. I very well could be a dumbass,especially just for the simple fact I'm working on my own personal vehicle. lol

Set meter to mA scale. Disconnect terminal at the battery, place meter leads accordingly, then the measurements should be there. If the domelight is on or anything else that draws alot of current then POP goes the fuse in the meter. You can't use voltage to diagnose the problem.

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Certified Security Specialist
Always check info with a digital multimeter.
I promise to be good.
Tell Darwin I sent you.

I've been sick lately, sorry I won't be on much.