Am I doing this right? Searching for battery drain

[Biggredd2069]

Having some bad battery draw. Took my volt meter, disconnected the negative and tested the negative pole on battery against the negative battery terminal and it's showing like 12 volt draw. No wonder my battery is dieing all of a sudden. But wasn't doing this before. I will admit I have a ton of aftermarket add ons to update the car but it's been holding up. So first thing I did was disconnect the positive battery terminal and the volts went to zero, still connected to the negative stuff. Seems self explanatory. So I have a bunch of positive connections to a hub there and I started disconnecting everything one by one and each time the volts stayed the same till I literally had removed each wire individually with no change in volts still on negative. Then I removed the entire positive terminal and again my volts dropped to zero. So something there is robbing me when parked but when I disconnected each thing individually I didn't get a change but if I remove it collectively it does. I did have a lack of sleep last night but what the hell.

 

[BigblueC]

I have no other input other than good luck. I hate chasing electrical gremlins.

 

[300rag]

Try it again, but instead pull all your fuses one by one until you find the circuit, and chase it down from there.

 

[Biggredd2069]

I did start pulling fuses but got tedious and was hoping that other method would work. Suppose I'll go back to that. Lol

 

[traintech55]

The most common electrical draws are,
1. Stuck glove box light.
2. Stuck trunk light.
3. Stuck cigar lighter, (up to 3 depending on car).
4. Stuck brake light switch.
5. Miswired Volt meter, (if equipped).
Good luck.

 

[Biggredd2069]

I have had stuck brake lights recently now that you mention it. I bet that's it. I'll check. Thanks

 

[BigblueC]

I have had stuck brake lights recently now that you mention it. I bet that's it. I'll check. Thanks

I hope that's your problem. That's generally an easy and cheap fix.

 

[Big_John]

Having some bad battery draw. Took my volt meter, disconnected the negative and tested the negative pole on battery against the negative battery terminal and it's showing like 12 volt draw. No wonder my battery is dieing all of a sudden. But wasn't doing this before. I will admit I have a ton of aftermarket add ons to update the car but it's been holding up. So first thing I did was disconnect the positive battery terminal and the volts went to zero, still connected to the negative stuff. Seems self explanatory. So I have a bunch of positive connections to a hub there and I started disconnecting everything one by one and each time the volts stayed the same till I literally had removed each wire individually with no change in volts still on negative. Then I removed the entire positive terminal and again my volts dropped to zero. So something there is robbing me when parked but when I disconnected each thing individually I didn't get a change but if I remove it collectively it does. I did have a lack of sleep last night but what the hell.

Yep, you're doing it wrong.

Measure amperage, not voltage. Watch this for proper instruction.

 

[Big_John]

Now that you've done that.

If I'm reading what you are saying correctly, the battery is still going to zero when everything is disconnected.. and by everything, I mean the battery terminals. Is that correct? That would be a bad battery.

 

[300rag]

Now that you've done that.

If I'm reading what you are saying correctly, the battery is still going to zero when everything is disconnected.. and by everything, I mean the battery terminals. Is that correct? That would be a bad battery.

He is getting 0v open circuit reading between -post and ground when the + battery post has been disconnected, which would be correct if all loads are off.

 

[Biggredd2069]

So I did take the battery to auto zone this morning and did a quick charge and a test, measured ok. For clarification on what I'm doing I'm leaving the positive battery terminal on. Taking the negative of the battery and holding that up in the air and using my testing terminals on the negative battery terminal and the other one on the negative cable I'm holding in the air to confirm drain. If I remove the positive I go to zero on the negative terminals I'm testing. But when I remove the individual positive wires one by one I still get reading on that negative side test. I'll continue down the fuse path. I only switched to this cause I ended up breaking a fuse and don't wanna go down the path of fixing one thing breaking another but that's just what it has to be. I'll be back out there in about an hour to resume testing.

 

[Big_John]

So I did take the battery to auto zone this morning and did a quick charge and a test, measured ok. For clarification on what I'm doing I'm leaving the positive battery terminal on. Taking the negative of the battery and holding that up in the air and using my testing terminals on the negative battery terminal and the other one on the negative cable I'm holding in the air to confirm drain. If I remove the positive I go to zero on the negative terminals I'm testing. But when I remove the individual positive wires one by one I still get reading on that negative side test. I'll continue down the fuse path. I only switched to this cause I ended up breaking a fuse and don't wanna go down the path of fixing one thing breaking another but that's just what it has to be. I'll be back out there in about an hour to resume testing.

Just watch the video first and do it the right way this time. You are looking for amperage draw, not voltage. Doing it the way you've been doing it will tell you nothing... as you've found out.

 

[Big_John]

He is getting 0v open circuit reading between -post and ground when the + battery post has been disconnected, which would be correct if all loads are off.

And that tells you nothing.

 

[73Coupe]

Sometimes you can have current percolation between terminals across the accumulated residue on top of the battery. That's why batteries must be always maintained in a clean state. They make battery cleaner just for this application.
Edit: This won't drain a battery overnight, though....

 

[73Coupe]

Yep, you're doing it wrong.

Measure amperage, not voltage. Watch this for proper instruction.

This guy is the best. He also has a good video on voltage drop. Excellent material.

 

[Biggredd2069]

Ok. The video was great. I switched my volt meter and turns out im only drawing .07 at the moment, which sounds like an acceptable range on that video. So back to square one of why. Through the course of rebuilding my engine and trying different things on the way I've killed this relatively new battery multiple times (2.5 years old). Wonder if it's just good enough to test well but really be on the outs. There has been a couple times, but rarely where I came home and my rear lights stayed on and I couldn't turn them off. Maybe that happened last night, all I know is it sucks having a cool car at a restaurant and having to do the walk of shame cause it won't start. Lol. Was getting confident too that I was finally starting to get everything dialed in and then this again.

 

[Big_John]

Ok. The video was great. I switched my volt meter and turns out im only drawing .07 at the moment, which sounds like an acceptable range on that video. So back to square one of why. Through the course of rebuilding my engine and trying different things on the way I've killed this relatively new battery multiple times (2.5 years old). Wonder if it's just good enough to test well but really be on the outs. There has been a couple times, but rarely where I came home and my rear lights stayed on and I couldn't turn them off. Maybe that happened last night, all I know is it sucks having a cool car at a restaurant and having to do the walk of shame cause it won't start. Lol. Was getting confident too that I was finally starting to get everything dialed in and then this again.

Each time you "kill" a battery, you shorten its life.

What happens is the battery plates will become covered in lead sulphate every time it's discharged. Get it below 90% and it starts getting bad. Below 80% and you only have to do it about a dozen times and it's toast.

In normal operation, the sulphate burns off as the battery is charged, but when it's deeply discharged, the sulphate buildup is too much to burn off.

So, a 2 1/2 year old battery that's been discharged a bunch of times is not going to be what I would call a good battery. The guy at AutoZone that flipped burgers at his last job might have checked that battery and it's fine to spin over some 4 cylinder popcorn wagon import, but it might not be enough to turn over a real engine when it's hot (or cold if it's below zero LOL)

IIRC, you've got a bunch of electronic stuff, like maybe EFI and some stereo amps etc. going too. That adds some draws (memory) and is probably why you have the .07 amp draw with everything off. The video is really aimed at newer cars... I would bet that my car draws nothing (especially now the clock stop working) and there will always be a slight draw with a newer car's electronics.

BTW, cheapest place I've found to buy a battery is Costco.

So... If your electronics let you, a battery disconnect might be in order. I have one on both my cars and when they are parked for any extended period, the battery gets disconnected.

 

[Biggredd2069]

I was thinking of a battery disconnect but I had my car on a tender the night before and this was just the very next day. But your also correct I do have efi and a updated stereo and a couple smaller entertainment accessories. May just suck it up soon and buy a new battery now that I'm done with my major upgrades and issues that led up to those upgrades. I've moved on to just fixing maintenance things now.

 

[CBODY67]

I presume you have a Group 27 battery? What you might get is a dual-terminal battery so that you can have TWO positive and TWO negative terminals to hook things to, which might simplify the wiring a bit? You might also need an alternator upgrade, too?

Remember, too, that a diode in the alternator can both decrease the alternator's output and let voltage run the wrong direction, which will not help things either.

Be SURE all of your battery terminals are clean and free of ANY gunk. A gunky connection can decrease alternator output by 10amps or so, even if it might not look significant.

You might also find a repair shop that can do a "charging system check", rather than just getting the battery checked. That way, with everything connected and turned on, you can see just what the alternator is producing and what all of your items are consuming when in use.

Just some thoughts,
CBODY67

 

[Biggredd2069]

I did upgrade to a 90 amp alternator. Am doing the one wire method . Although I was having an issue with charging early on and I got a long battery wire and went direct from the alternator to the battery. Made a world of difference. I bought a multi unit positive terminal connector so each of my accessories are divided into separate connection points.

I think your point about just going to a shop and doing a charging test might be a better next step. I ain't gonna lie...I love working on my car and learning things. I at least want to say I tried on my own and have the knowledge for later. But sometimes you just need a Damn professional to help.