Draining Battery

[PoorMtnKid]

So ever since getting my car back from the shop that tuned it my battery has constantly been draining. I would fully charge the battery and in less than a week it would be so drained that it would not even click with trying to start. No lights worked our gauges, just completly drained.

I checked it one day when this happened and it was down to 6 volts. So I went to wonderful youtube and watched a video on how to find a parasidic draw. I followed the steps using my multi meter and I could not find anything drawing power by pulling the fuses. It read somewhere around 0.28 Amps. I checked my Jeep for comparison and it read 0.35 Amps. So it would seem that nothing is pulling power, so what is the cause.

The next check I did is still in progress. I fully charged the batter on Sat. I disconnected both positive and negative battery cables and with my multimeter have been checking the volts. This is the readings that have followed:

Day 1 after full charge- 13.06
Day 2 AM- 12.98
Day 2 PM- 12.96
Day 3 AM- 12.93
Day 3 PM- 12.90
Day 4 AM- 12.86

So its obviously dropping but I just dont know if this is normal or is my battery bad and it wont hold a charge? I have taken the battery to Autozone and they tested it and said it came out fine but obviously something is wrong. Any insight on this would be great. When I get home I will get another reading and see how much it has dropped since this morning.

[two_68_510s]

What is the output of your alternator?
Is that the "surface charge" dissipating? How low does it go?

[okayfine]

So its obviously dropping but I just dont know if this is normal or is my battery bad and it wont hold a charge?

Batteries will fluctuate voltage over time given differences in enviro, etc. They discharge over time as well. This is relatively normal.

The shop tuned your car. Did they add anything electronical, or otherwise screw with anything but software?

I would fully charge the battery and in less than a week it would be so drained that it would not even click with trying to start. No lights worked our gauges, just completly drained.

Over the course of a week, this is abnormal, obviously. How much driving did you do over this week above?

how to find a parasidic draw. I followed the steps using my multi meter and I could not find anything drawing power by pulling the fuses.

Which only means that if you have a drain, that drain doesn't go through the fuse box.

Do you have a test light? You can make one easy with a parking bulb, if nothing else. Disconnect the Positive off the battery and put the test light in between the + cable and the + terminal. If it lights, there's something pulling power from the battery.

Now, this could easily be the constant-hot from your stereo, so you'll also have to determine the power draw (milliamps) across that same connection.

The other possibility is that your car isn't charging the battery, and so you're running around just on battery power and not the alternator. You could get a fair few miles on battery alone if you didn't have much use for headlights.

So, review what, if anything, the shop did to your car. They may have wired the ECU to constant instead of switched. What other circuits do you have that are not fused? What sort of power draw do you have with everything off? And are you sure you have a functioning charge system?

[PoorMtnKid]

When I took the car to get the tune they did say my altenator was bad and they had me replace it. I kinda feel like I was taken for a ride on this one but the "new" altenator is charging the battery. At idle it reads 13.5 volts.

As for the "surface charge disapating" I dont quite understand the question.

Between the time of fully charging to it being 6V there was not a single day I drove the car. I did start it 3 times and let it run for 5 min or so to keep the battery charged. This was all done at idle while the car was on jack stands.

The only thing that was installed on the ECU for the tune was a nissan consult port so he could hook up to do the tune. I do not have a radio in the car and the only things I could think that are direct power are my fans I have to switch on constand power and my GPS speed-o has a constant power. Which this is not needed but I did just splice this into a wire behind the dash so I would assume this is going to a fuse.

[okayfine]

The alt isn't really doing much charging at idle, but at 13.5V or so, fair to say that's not the problem. Certainly sounds like you have a big drain in the system. Consult port shouldn't have any power connections. Can you disconnect your speedo from the system, then test at the battery with a test lamp? I wouldn't think a speedo could pull that much power over time, but if it's ON all the time and polling for satellites all the time, that could be. Much like how certain settings and features on a phone will drain a battery quite quickly. Definitely worth eliminating as a suspect.

[PoorMtnKid]

The alt isn't really doing much charging at idle, but at 13.5V or so, fair to say that's not the problem. Certainly sounds like you have a big drain in the system. Consult port shouldn't have any power connections. Can you disconnect your speedo from the system, then test at the battery with a test lamp? I wouldn't think a speedo could pull that much power over time, but if it's ON all the time and polling for satellites all the time, that could be. Much like how certain settings and features on a phone will drain a battery quite quickly. Definitely worth eliminating as a suspect.

The cell phone reference makes perfect sense. I will eliminate that tonight and see what happens. In regards to the micky mouse test light with the parking bulb. Do I just place the bulb in between both points and it should light up if there is a draw?

[okayfine]

$5 test light at your FLAPS,
http://www.harborfreight.com/automotive ... 30779.html

or solder some bits of wire to the side (ground) and center (+) of a 12V bulb and connect them between the +battery cable and the +terminal. It will light if there's something pulling power.

[PoorMtnKid]

looks like I will be stopping by the harbor. So when I get this I need to connect one side to the postive battery terminal and the pointer side of the light to the actualy cable. When I do this the light should come on because I have a drain correct? Then after I disconnect my GPS , hopefully the light will be gone?

[okayfine]

When I do this the light should come on because I have a drain correct?

Yes.

Then after I disconnect my GPS , hopefully the light will be gone?

Hopefully.

[PoorMtnKid]

Just used the test light like you suggested, no light came on. That's with out messing with the GPS signal wire. To test the theory I turned one of my fans on at the switch and sure enough the light came on.

[okayfine]

That's...unexpected. What's the history of the battery? Type/brand, years in service, etc?

[PoorMtnKid]

That's...unexpected. What's the history of the battery? Type/brand, years in service, etc?

I had the battery when I had the L16. It's a cheap autozone brand I think called auto lite. 650 crank amps. Checked just now the volts and its sitting at 12.86

[okayfine]

I don't know what/how they test batteries, I know they put a "load" on them and such, but it's Greek to me. Perhaps it is possible for a battery to pass their test but be past its prime? Do you have a known-good battery you could swap in and see if you also get the discharging over time?

[PoorMtnKid]

That's my next step. My dad has an optima just sitting at home that he knows holds charge. He's brining it over tomorrow when we finish my ZG flares to test that one.

[510wizard]

Another possibility is that you have leaky diodes in that new alternator. I am not a fan of using lamps to check current draw, if the draw is low, the filament in the lamp would be very faint, which would be hard to see. Also with the lamp method you wouldn't know what the current draw (drain) actually is. I would see if you can borrow a mutlimeter that can measure milliamps.