Electrical Battery Drain / slight draw

R82148V

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May 26, 2020
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Okay here it is and I'll try to make it quick... I've been chasing a parasite draw for some time now and I believe I have two.. Have a new batt. All over the internet it states you should be in the .50mA or less range. I was reading 3.25 and the batt would drain pretty quickly over a short period of time. Pulled all fuses which didn't make a difference. I read that it could be the Alt. Since it was the stock alt, I pulled the "D" connector and that seemed to bring it down to 2.85. I figured this was a good time to upgrade to a 3G. Installed the new alt and the draw now stayed at 2.85. The batt doesn't drain as bad but it does come down so now im looking for the other draw. I disconnected all four connections on the + side of the Starter solenoid except the batt cable of course. The draw was gone! I tried each connection, one at a time, back on the solenoid and found that the 2.85 draw came back once the "blue" connection was on. Going through wiring diagrams, this is KAM, EEC power relay and a few other things, but I'm having a hard time understanding the diagrams. I started to pull everything and nothing brings down that 2.85. I pulled the EEC power relay, ignition module, fuel pump relay, WOT relay, you name it! Nothing brings it down.

The batt voltage was 12.73 volts last night around 9:30pm
This morning, I checked it 9am and its down to 12.71.

I know KAM has a constant draw but I don't know how much its supposed to be and or how much should your batt drain down daily.
I dont have a radio in it or anything aftermarket. Like I said, All fuses out and the draw is still there.

I'm stumped. Am I just chasing ghost or am I on to something?

Thanks!
 

Mustang5L5

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By "blue" connection, do you mean the blue fusible link?

What year is the car?

So are you saying that pulling the EEC power relay does not cause the draw to drop? If that's the case, unplug the ECU. The wire that feeds the EEC relay also jumps to feed pin 1 on the ECU. It's possible that is the source of the draw.

With the ECU and EEC relay remove, there should be no draw. If there is, then the wire may be shorting somewhere between the starter relay connection block and the pass kick panel area.

1654197640390.png
 

R82148V

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May 26, 2020
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Sorry about that..
Correct. The "blue" connection, meaning the blue fusible link.
This is an 87.
Yeah, when the EEC relay is pulled, the draw stays the same. I'll pull the ECU, like your suggesting and report back the findings!

Thanks again!
 
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7991LXnSHO

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By "blue" connection, do you mean the blue fusible link?

What year is the car?

So are you saying that pulling the EEC power relay does not cause the draw to drop? If that's the case, unplug the ECU. The wire that feeds the EEC relay also jumps to feed pin 1 on the ECU. It's possible that is the source of the draw.

With the ECU and EEC relay remove, there should be no draw. If there is, then the wire may be shorting somewhere between the starter relay connection block and the pass kick panel area.

1654197640390.png
Is the .5 milliamp figure correct? That’s .006 watts.
 

R82148V

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May 26, 2020
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Before changing the Alt, I was drawing 3.25 mA and the batt would drain in a few days.
After changing the Alt, it dropped down to 2.85 mA and the batt does now lasts longer, dropping from 12.73 to 12.70~1 volt over night but not sure if its just the KAM or something including the KAM. This 2.85 draw was isolated coming from the Blue wire off the starter relay.
1654204273586.png
 

Mustang5L5

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Is the .5 milliamp figure correct? That’s .006 watts.

30-50 milliamps is probably more accurate for most of our old, inefficient cars. Newer vehicles are likely lower. A lot of that has to do with what sort of stereo or other accessories you have you have and what current it draws for its KAM.

Edit: my car pulls 30 milliamps at rest, and I can go a month easily without using the battery tender and it will still start.

Double edit: found a Nissan specification that lists a at rest current draw of 22 mA or less is acceptable.
 
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7991LXnSHO

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30-50 milliamps is probably more accurate for our cars. A lot of that has to do with what sort of radio you have and what current it draws for its KAM.

I’d have to look back at the post I made about 3 weeks ago but I think I’m at 35 milliamps at rest. I have a stock radio, the ECU and my homelink electronic mirror using KAM.
I think at .5 milliamp, I could count the individual electrons go by with a strong enough microscope and new glasses. :D
Thanks for the verification.
 

Mustang5L5

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Before changing the Alt, I was drawing 3.25 mA and the batt would drain in a few days.
After changing the Alt, it dropped down to 2.85 mA and the batt does now lasts longer, dropping from 12.73 to 12.70~1 volt over night but not sure if its just the KAM or something including the KAM. This 2.85 draw was isolated coming from the Blue wire off the starter relay.


I’m still puzzled how you are draining your battery on a 3mA draw.

I’m sitting at 30 milliamps at rest and can easily go a month between starts without issue.
 
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7991LXnSHO

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@Mustang5L5 , me too.
After the CPU is unplugged and tested,
1. I’m really wondering what that new looking battery would do under a load test.

2. I’m also wondering about a periodic draw. Besides wiggling the wire looms and watching the meter, that’s a nightmare thought.
 

R82148V

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May 26, 2020
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right!! it doesn’t make sense. the mA being so low how the heck was is draining the batt at 3.25mA. I thought i was just reading the meter wrong and 3.25 really was 3 hundred 25. hahah So when i pulled the old Alt wire off for the heck of it and some of the mA came down, it really helped some on the draw and i was surprised.

No radio in the car at all.
I just pulled the Ecm harness off and the draw dropped to zero. put it back on and it went back up to 2.85.

Could / would heated 02 sensors have something to do with it?

I can always just wiggle wires to see what happens too.
 

Mustang5L5

Put lubricant all over the balls
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Feb 18, 2001
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No radio in the car would eliminate a lot of the at rest current draw. As far as I know only the ECU and the radio would have KAM.

That makes sense that you only see current draw on the blue fusible link as it feeds pin 1 on the ECU with constant power. With the ECU disconnected you should have nothing or pretty darn close to it.

But like said, 3 mA is nothing already. That shouldn’t be killing your battery.

Take the battery to Autozone and have it load tested. Or buy this and try it

Limited-time deal: Schumacher BT-100 Battery Load Tester and Voltmeter - 100 Amp Amazon product
View: https://www.amazon.com/dp/B000AMBOI0/ref=cm_sw_r_cp_api_i_dl_0YVGNE8W4XDWJZNV36TQ?_encoding=UTF8&psc=1