Halp diagnosing vehicle parasitic current draw.

[ARCHIVED THREAD] - Halp diagnosing vehicle parasitic current draw.

Posted: 11/17/2011 3:43:22 PM EDT

So my truck, an 04 Colorado ( I know GM is crap ) is experiencing a weak battery as of lately. Go to turn it over and the starter engages slowly but still turns on. Voltage with vehicle on is right at around 14.6 - 14.5V

Granted the battery has been in there for 3 years and 2 months. Its a VatoZone Duralast Gold which has a 3 year free replacement and 8 year prorated warranty. The battery at rest has 12.4 Volts on it which is a tad low. battery terminals and tight and clean.

I measured the current draw from the battery into the truck and it has a 20mA draw sitting idle and 100mA draw once the alarm is activated. The truck has 2 alarms interfaced into it. The stock one and a aftermarket since the aftermarket one works off of the stock wires as a add on. Its the DEI Hornet 727T.

Does 100mA seems excessive? I'll take the battery to Vatozone tomorrow and have them test it just to make sure. What say you guys?

Posted: 11/17/2011 3:44:16 PM EDT

[#1]

Tag. My forklift has a mysterious drain too.

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Posted: 11/17/2011 3:45:39 PM EDT

[#2]

Same thing happened to my 98 Jimmy new battery fixed the problem

Posted: 11/17/2011 3:48:52 PM EDT

[#3]

Put an ampmeter inline with the battery and start pulling fuses. When the amp draw drops to near zero, you found your circuit.

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Posted: 11/17/2011 3:50:42 PM EDT

[#4]

Quoted:
Put an ampmeter inline with the battery and start pulling fuses. When the amp draw drops to near zero, you found your circuit.

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I assume between the positive post and its lead?

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Posted: 11/17/2011 3:51:45 PM EDT

[#5]

Mine was my LoJack, which was installed inside a brake light.

Does yours have one of these hidden in it?

Posted: 11/17/2011 3:56:21 PM EDT

[#6]

Quoted:
Mine was my LoJack, which was installed inside a brake light.

Does yours have one of these hidden in it?

No Lo-Jack here. I didnt have this problem before so I want to guess the battery might be going bad from not being used enough since the truck is an 04 and barely has 42K miles on it. I ride my motorcycle most of the time.

I'll check the current draw again and pull fuses to see whats going on.

Posted: 11/17/2011 4:06:12 PM EDT

[#7]

Quoted:
Put an ampmeter inline with the battery and start pulling fuses. When the amp draw drops to near zero, you found your circuit.

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ive got this problem as well... wife says the truck won't start... the battery reads 1.85v.

Do I check the amps with the circuit on, or not?

Posted: 11/17/2011 4:08:50 PM EDT

[#8]

Quoted:
Put an ampmeter inline with the battery and start pulling fuses. When the amp draw drops to near zero, you found your circuit.

Posted Via AR15.Com Mobile

Test light does the same thing, when the light goes out, thats the problem area.

Posted: 11/17/2011 4:18:52 PM EDT

[#9]

100ma is excessive. 20ma is tits. Any time I see an aftermarket alarm and a draw , the alarm gets shitcanned. Your Autobone battery needs testing, simple to do with a proper battery tester, hard to learn much with a DVOM.
The idea with using a test light is kinda old school, it applies a lot less now that vehicles have modules that go to sleep over time every time the key is switched off. Have you measured the draw over time, say 30 minutes, to see if it is still 100ma?
connect your ammeter and let it sit for an hour, then use the test light to see which fuses are hot at the time. Only pull those fuses while watching for the meter to change. Then you have a path to trace the draw.

Posted: 11/17/2011 4:24:36 PM EDT

[#10]

Quoted:
100ma is excessive. 20ma is tits. Any time I see an aftermarket alarm and a draw , the alarm gets shitcanned. Your Autobone battery needs testing, simple to do with a proper battery tester, hard to learn much with a DVOM.
The idea with using a test light is kinda old school, it applies a lot less now that vehicles have modules that go to sleep over time every time the key is switched off. Have you measured the draw over time, say 30 minutes, to see if it is still 100ma?
connect your ammeter and let it sit for an hour, then use the test light to see which fuses are hot at the time. Only pull those fuses while watching for the meter to change. Then you have a path to trace the draw.

I haven't let it sit for more than maybe 2 or 3 minutes since i was outside at work holding the probes to the negative cable and the battery terminal. Once I get home I will connect it up and let it sit a while and see if its just the vehicle needing to stabilize before that draw goes down a bit more.

I do have a battery load tester at home. I'll have to dig it up out of the attic or wherever it is.

EDIT:

I had forgotten I had written this on another forum 3 years ago when I was trying to figure out I needed a new battery at that time. Its possible my battery is just the issue.

" Initial current parasitic current drain was at 500mA when first measured by removing the negative cable, then after about 1 minute it dropped down to 90mA, overnight it dropped to 30mA. I guess all the electronics and such inside the truck have to recharge their circuit capacitors when discconected. I think we are all good now. "

Posted: 11/17/2011 4:36:58 PM EDT

[#11]

Quoted:

Quoted:
Put an ampmeter inline with the battery and start pulling fuses. When the amp draw drops to near zero, you found your circuit.

Posted Via AR15.Com Mobile

Test light does the same thing, when the light goes out, thats the problem area.

Test light does not give you an accurate reading on amount of draw.

Posted: 11/17/2011 4:38:47 PM EDT

[#12]

Quoted:

Quoted:
Put an ampmeter inline with the battery and start pulling fuses. When the amp draw drops to near zero, you found your circuit.

Posted Via AR15.Com Mobile

ive got this problem as well... wife says the truck won't start... the battery reads 1.85v.

Do I check the amps with the circuit on, or not?

Leave everything off that would normally be off when the vehicle is not running. If you are using a multimeter and exceed 10 amps, you can blow the fuse in the meter.

Posted: 11/17/2011 4:39:15 PM EDT

[#13]

Quoted:

Quoted:
Put an ampmeter inline with the battery and start pulling fuses. When the amp draw drops to near zero, you found your circuit.

Posted Via AR15.Com Mobile

I assume between the positive post and its lead?

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Correct.

Posted: 11/17/2011 4:41:16 PM EDT

[#14]

20ma draw is fine, and the 100ma draw was probably only while the computer was shutting down. It takes about 45 minutes to get into sleep mode.

Replace the battery with a better one. Don't cheap out on your battery. I used Interstate "MTP" series batteries, and have no issues even when I abuse them.

Posted: 11/17/2011 6:35:48 PM EDT

[#15]

Quoted:

Quoted:
Put an ampmeter inline with the battery and start pulling fuses. When the amp draw drops to near zero, you found your circuit.

Posted Via AR15.Com Mobile

ive got this problem as well... wife says the truck won't start... the battery reads 1.85v.

Do I check the amps with the circuit on, or not?

Leave everything off that would normally be off when the vehicle is not running. If you are using a multimeter and exceed 10 amps, you can blow the fuse in the meter.

Makes perfect sense... ive blown the fuse on my DMM a few times with high power flashlights... but if anything in the truck is pulling 10 amps when its not running I think I have real problems.

This thread probably saved me some time this weekend.

Posted: 11/17/2011 6:36:22 PM EDT

[#16]

Quoted:
( I know GM is crap )

Well I'm done reading. Good luck.

Posted: 11/18/2011 4:48:46 AM EDT

[#17]

Got truck home this morning and busted out my DMM. After a 30 min drive battery voltage siting was 12.35V. Thats low, should be more like 12.6V.

Truck on and idling is 14.36V which indicates charging system is working OK.

Found my load tester. After applying the load to the battery for 10 seconds it pulls the battery down to the 8-9V range.

Connected DMM as Ampmeter and initial current draw was right at 500mA, After a minute or so it dropped to 100mA In about 1 hour it dropped down to 50mA which according to what I found online for this model truck should be fine.

I guess the load testing killed the battery since it didnt want to start this morning. I have it on a charger and hopefully will charge up a but so I can run to Vatozone to exchange the battery.

Posted: 11/18/2011 7:23:44 AM EDT

[#18]

Went to VatoZone. They determined battery was bad. Got a new one. Wasn't a free replacement since I was 2 months over the 3 year warranty but it was significantly less. Now I need to replace these shitty stamped battery terminals with some heavy duty military grade ones as below. I have the battery on the trickle charger and willl leave it there for about 4 hours or so that way it can reach peak performance.

Thanks to all that helped.

Posted: 11/18/2011 7:54:18 AM EDT

[#19]

had a similar problem on my 02 suburban.

Leave it sit for a few days with no running, and the battery would be dead. In my case, pretty sure it's the aftermarket remote start.

On the plus side, the Optima Red has been drained 5 times, and charged back to 100% with no issues.

Posted: 11/18/2011 8:00:10 AM EDT

[#20]

Yeah , 3 years from anything but top-of-the-line batteries is pushing it .
I like the Megatron's too . Just stuck one in my truck.

[ARCHIVED THREAD] - Halp diagnosing vehicle parasitic current draw.

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