Battery Help (Parasitic Draw)


c_bronson

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I could really use some help.

Some backstory: For about 6 months, I've faced some very intermittent battery issues. Or at least that's what I assume. Everything would be fine then one day I'd have trouble starting the Jeep but with some charging of the battery, it started right up. I didn't worry too much because it was extremely intermittent. A few weeks ago, my wife and I left town for about a week. During this time the Jeep sat not hooked up to a battery charger or anything. When we got back, I got in the Jeep and it fired right up no problem. I drove it to drop it off at a mechanic who was building me a roof rack. He had it for about a week. When I went to pick it up, he mentioned to me I had some sort of electrical/battery issue. I trust this guy and he isn't a random mechanic I picked. He told me he had to jump the jeep almost every time he started it while he had it. He explained I probably have a parasitic draw and showed me how to chase it down.

I then began chasing the parasitic draw I thought I had. I used my multimeter set to 10 DC Amps and undid the negative terminal and began testing fuses. The draw I originally had before testing fuses was 0.13 amps (130 mA). I got no results on anything except fuse 20 in the PDC (1999 Jeep Wrangler Sahara 4.0). I noticed when I pulled out fuse 20 the current dropped to 0.001. So I researched and found that fuse powers several things like radio, interior lamps, and the OBD II port. I found when I removed C108 from the 100 pin connector driver side, it was the same result as pulling fuse 20. I tried this on all pins under there to make sure it was narrowed down to that one. I then began testing wires on that connector (Blue) and go nothing. I went to set up my multimeter in a way where I could see it from the windshield while working under the dash and every time I had it set up and walked around to the start testing wires, the amps had dropped from 0.13 to 0.001. So I went back and re-connected the multimeter and got the 0.13 amps and I held it there and after about 15-20 seconds it dropped to 0.001.

I also in the middle of all this went and had my battery tested and realized after 10 years it was shot. So I opened the wallet for a NorthStar AGM. I notice that when I test the alternator on both batteries I was only getting about 13.6 volts which is lower than I'd want but still acceptable. I don't THINK my alternator is quite in need of replacement.

Anyway....all that to say/ask: Do I actually have a parasitic draw or is the 0.13 Amp and eventual drop 0.001 a non-issue? And is my alternator okay? (I've tried to bold the key information above to help out...sorry for the long post.)
 

glowell222

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You never stated which component on C108 was causing the draw-did you isolate the component and rectify the issue?
 
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c_bronson

c_bronson

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You never stated which component on C108 was causing the draw-did you isolate the component and rectify the issue?
No, I tested each wire on C108 and was unable to get the draw to appear. It was then that I was going to try for a third time messing with each wire and position the multimeter on the windshield when I noticed the draw was going away after 15-20 seconds. So I stopped and decided to get some insight from the forum.
 

glowell222

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Understood.

I would do a timed session, and see if, after any period of time, the draw comes back. I would check on a fifteen minute plan-does the draw actually drop to .001 and stay there, or are you having some kind of cyclical or intermittent issue. Also, if you know someone who has a different meter than yours, see if you can borrow it to get a second opinion, so to speak.
 
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c_bronson

c_bronson

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Understood.

I would do a timed session, and see if, after any period of time, the draw comes back. I would check on a fifteen minute plan-does the draw actually drop to .001 and stay there, or are you having some kind of cyclical or intermittent issue. Also, if you know someone who has a different meter than yours, see if you can borrow it to get a second opinion, so to speak.
Alright, I'll give that a shot and see what happens.
 

glowell222

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With regards to your alternator, what typically goes bad is the voltage regulator, and this can be replaced. 13.6 VDC is within the spec, I think, and I would just start to plan for a new reg or alternator at some point. Hard to say with precision. Also, a bad battery can give you intermittent issues such as you are describing, with working great some times and then needing help each time. Particularly if it was a Methuselah battery of 10 years-that must be the record for old batteries! (That last sentence is poor grammar but I am fried from the day)
 
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c_bronson

c_bronson

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With regards to your alternator, what typically goes bad is the voltage regulator, and this can be replaced. 13.6 VDC is within the spec, I think, and I would just start to plan for a new reg or alternator at some point. Hard to say with precision. Also, a bad battery can give you intermittent issues such as you are describing, with working great some times and then needing help each time. Particularly if it was a Methuselah battery of 10 years-that must be the record for old batteries! (That last sentence is poor grammar but I am fried from the day)
Yeah I kind of figured the battery was at the end of its life! And to give it credit, it was an AC Delco that lasted 10 years so I was very impressed.

I went ahead and ran down two houses to my friends and grabbed his multimeter and did a test like you mentioned. In a period of 20 minutes, after it dropped from 0.13 to 0.015 (I realize above I was saying 0.001 and I meant 0.01) it did not go back up at all at any point.
 

CodaMan

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130 milliamps is not enough to worry about. Your radio, PCM and OBDII port will use that. If your batteries are going dead with that little parasitic draw you have other problems.
 
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CodaMan

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With regards to your alternator, what typically goes bad is the voltage regulator, and this can be replaced. 13.6 VDC is within the spec, I think, and I would just start to plan for a new reg or alternator at some point. Hard to say with precision. Also, a bad battery can give you intermittent issues such as you are describing, with working great some times and then needing help each time. Particularly if it was a Methuselah battery of 10 years-that must be the record for old batteries! (That last sentence is poor grammar but I am fried from the day)
How do you change the voltage regulator since it's built in to the PCM?
 
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c_bronson

c_bronson

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130 milliamps is not enough to worry about. Your radio, PCM and OBDII port will use that. If your batteries are going dead with that little parasitic draw you have other problems.
I originally did not think it was much to worry about but everything I found said parasitic draw should be less than 100 mA and closer to 50 mA if possible. I just don't want anything to negatively affect the $300 battery I just bought today. I would like it to last as long as my old one if possible.
 

CodaMan

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I originally did not think it was much to worry about but everything I found said parasitic draw should be less than 100 mA and closer to 50 mA if possible. I just don't want anything to negatively affect the $300 battery I just bought today. I would like it to last as long as my old one if possible.
I don't know what my Jeep has, but for reference my pickup has 160 mA and I have no problems.
 

Goatman

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Throwing a dart here...
My interior lights stay on for 15-20 seconds after I cycle the key off. Any chance you are detecting that circuit with its delay drawing that bit of amps? Or perhaps your radio has a similar delay circuit?🤷‍♂️
 
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c_bronson

c_bronson

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Throwing a dart here...
My interior lights stay on for 15-20 seconds after I cycle the key off. Any chance you are detecting that circuit with its delay drawing that bit of amps? Or perhaps your radio has a similar delay circuit?🤷‍♂️
While my lights don't stay on I didn't think about that for other circuits. You might be right on with that thought.
 

Head Lice

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That's a pretty cool setup! You have any issues with a secure fit while driving or off-roading? Or is it pretty snug?
It's very well made in the USA, can be taken apart to re-arrange the configuration to fit your application. My TJ can sit for a couple of weeks and the battery will become quite 'groggy' . . . . this fixes that. My OEM radio will retain all the station memory, but the clock will need a re-set. Very happy with this product and application.