Just a little PSA on some battery parasitic drain testing I've been doing today on my Z28. I went to fire it up this week to head to work and I couldn't unlock the car with the remote. Used the key to open door, hood, then pulled a voltage reading. 2.4 volts. I don't think I've ever seen a battery this low in any of my cars before and it made me wonder if I had a bad electrical component causing a parasitic drain. Battery was replaced under warranty.

Today, I setup an amp meter on the 10 amp scale, made the connections, hit the lock on the remote, and pulled a reading. ~67mA or ~0.067A. It was moving up and down a couple mA, but that was because of the security LED blinking on the dash. On page 6D1-4 of the factory service manual, there is info on how to test for a parasitic drain using some special tool, but I just used an amp meter in series. The FSM listed normal current pull for when all modules go in to sleep mode is under 20mA, but 25mA is listed as acceptable as well. I didn't see where it listed how long it took for the modules to go to sleep, so I timed it.

~10mins after I pressed the lock button on the remote, I heard a relay click and the current went from 67mA to ~7mA.

So the car is good on it's idle current draw and I must have got a bad battery. Just wanted to post this up for those who may need to test for parasitic current draw.

As a side note, the chart on 6D1-5 breaks down what some various devices should pull after the 10min mark. The numbers are in mA, but they don't list scale in the chart.....which is a fail in my book as it could be mistaken as amps.

I will get some pictures up later and also will test with a DC amp clamp to see if it would be sensitive enough to not need a series amp meter setup as that can be a pain if you don't have a way to clamp the leads to the battery and/or car chassis. I pushed the bolt out of the negative battery wire, installed it in the battery negative connection to use it as a post for one the amp meter leads. The other lead went to the chassis.

Edit:
Just attempted pulling readings with my two amp clamps and the mA accuracy is just not present. The readings were over 100mA higher than having the amp meter in series. It's best do to this measurement with an amp meter in series. Below are what my readings looked like....
Before Module Sleep:


After Module Sleep:

 

Very helpful procedure. I just learned how to do this last week on another vehicle.

 

Yeah, if you are not aware of when the modules go to sleep, you would end up chasing a problem that is not real. Just edited my first post with the results of my amp clamp attempt and pictures.

 

How is everything going?

 

Very unusual to have a new member from Ireland (as indicated in your profile, and by your IP address). Please tell us about your Camaro. We really enjoy seeing photos of Camaros from outside the U.S.