Battery drain advice for a rookie (Page 1/2)
Kitskaboodle OCT 01, 09:49 PM
Hi all, I would like to solve a battery drain problem on my 90 Buick Reatta. After charging the battery and then letting the car sit for about a week, the battery will be about 2/3 to 3/4 depleted of its charge. (it will barely crank the starter)
And no, I did not leave on any lights or anything else on. As a temporary fix, I keep a small socket wrench in my car and disconnect my negative cable whenever I know it will be sitting for 3-4 days or more. It solves my problem temporarily but I would like to fix the root cause of this drain.
That being said, I have a “good” ohmmeter but I would consider myself a rookie at electrical troubleshooting.

Any advice on some simple things / simple tests that even I can do to narrow down the problem?
Thanks, Kit
Patrick OCT 01, 10:52 PM

I found the advice in the following thread helpful to finally locate the issue I had years ago with my '94 Elantra.

Battery Drain
Kitskaboodle OCT 02, 01:54 AM
Thanks for the link Patrick. 😀
I read it carefully.
I do have one question though.
First step is to disconnect battery cable, set ohmmeter to DC 10A setting (or the DC MA setting) and then place ohmmeter leads between the battery cable and the battery and check reading.
From your thread / link there were some people doing this through the negative cable but one person said they did this drain test through the positive side.
Does it matter which side of the battery you check drain from??
Kit

[This message has been edited by Kitskaboodle (edited 10-02-2022).]

Patrick OCT 02, 02:03 AM

quote
Originally posted by Kitskaboodle:

From your thread / link there were some people doing this through the negative cable but one person said they did this drain test through the positive side.
Does it matter which side of the battery you check drain from??



Reading over my own posts in that six year old thread, I connected my multimeter to the negative side of the battery. I don't know if it makes a difference in the readings (I suspect it doesn't), but I do know that the negative side worked for me.

The big advantage of disconnecting the negative side of the battery (for the test) is that there is then no risk of shorting the positive side to ground.

[This message has been edited by Patrick (edited 10-02-2022).]

theogre OCT 02, 08:46 AM
First test the battery. Many stores now use computerize test not simple load teat.
Because Battery w/ weak/dead cell can last a few days, more not connected.

Then See my Cave, Battery Leaches
and https://www.fiero.nl/forum/...HTML/137471.html#p37

If has aftermarket crap, they often has problems.
Old disused cell phone parts, audio, security and more are found in old cars still connected.

Yes, Neg side has less risk of shorting etc.
But using DMM etc more then battery draw in cave and elsewhere is a waist of time and often do more damage when people taking apart end or cutting anything. DC Amp Clamp are way easier even if have some rules to follow. Like try to stay away from any motors because of magnets and heavy magnet fields in them messing w/ Hall Effect "chip" in the meter. You often need to Zero them when you move them then clamp a wire.

(In normal use and sure whatever is Off... Clamp a wire, Zero the meter, then turn On to read Amp Draw.)
Note: Many DC Amp Clamps can't read "negative amps" unlike many DMM wired in a circuit. If you read 0, turn 180° and check again.
You Think reads Magnet power on a wire and should not mater but some get pissed because of how the chip works.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

[This message has been edited by theogre (edited 10-02-2022).]

Kitskaboodle OCT 02, 03:13 PM
Ok, so I checked the battery drain on the negative battery cable and I’m getting 0.12 milliamperes.
From the thread info Patrick attached, that means I’m drawing 120 milliamperes, which is too much! Patrick reported 150 ma on his Elantra so I’m not far behind him.
Ok, now to start removing fuses one at a time. I will first focus on the fuse that gives power to what my Reatta buddy says is the “Passkey” box which he said is on all the time.
Stay tuned…,,Kit

[This message has been edited by Kitskaboodle (edited 10-02-2022).]

Kitskaboodle OCT 02, 05:23 PM
Ok, so my Reatta buddy came over today and helped me with the next test on the list. (I would pull all fuses and relays one at a time while he would read the meter) Results……after pulling all fuses and relays from all 3 of the Reatta fuse boxes, there was no change. Meter never varied from 0.11 to 0.12 draw. We then disconnected the alternator positive wire but there was no change.
So for now that’s all we had time for. Looks like it’s going to be an uphill battle.
Kit
MidEngineManiac OCT 02, 10:01 PM
It's kind of a cheater fix, but toss a solar trickle charger on it, at least until you find the actual culprit.
Kitskaboodle OCT 03, 10:52 AM
That’s a good idea. Thanks. 😀
I went to Amazon and checked several different solar panel models out. For me there are two negatives: I am a car cover kind of guy. (all my cars have them) so I would have to run the wires outside from the cigarette lighter or battery and then loosely place the solar panel on top of the car cover. Secondly, I heard some people say to be careful about using/buying one of the bigger solar panel’s because they can overcharge your battery.
All that being said, it’s just as easy to fix the problem (temporarily) by disconnecting the battery when I’m not driving the car for any length of time.
Kit

[This message has been edited by Kitskaboodle (edited 10-03-2022).]

Kitskaboodle OCT 03, 10:53 AM
That’s a good idea. Thanks. 😀
I went to Amazon and checked several different cigarette lighter models out. For me there are two negatives: I am a car cover kind of guy. (all my cars have them) so I would have to run the wires outside from the cigarette lighter or battery and then loosely place the solar panel on top of the car cover. Secondly, I heard some people say to be careful about using/buying one of the bigger solar panel’s because they can overcharge your battery.
All that being said, it’s just as easy to fix the problem (temporarily) by disconnecting the battery when I’m not driving the car for any length of time.
Kit