Parasitic Battery Drain/Draw ...couple troubleshooting tips to keep in mind:

[Jeepwalker]

Hey all. Had to track down a recent battery issue and look for a short. Just wanted to remind H3 owners trying to track down a draw or short to keep this one bit of info in mind:

After you unhook your battery cable and get your multi-meter leads secured to the battery terminal and the battery clamp, you need to leave your meter sit undisturbed (key off, doors closed) for about 30 minutes for the ECM to go into 'sleep' mode. Once it goes into 'sleep mode', or it's lowest inactive state, the amp draw should go to it's base level and you can then observe the base battery draw.

A method of getting around this wait is if the vehicle has been sitting for a while (the hood up--i.e. ECM is 'inactive'), a person could put a test probe on the battery post, tape or secure the other probe to the battery clamp, and carefully lift the clamp off the post while keeping connection with the test probes. View the amp reading, then gently replace the battery terminal clamp. If the meter probes slip, the ECM will suddenly wake up and go to a higher amp draw state (~.84-ish) and you'll have to wait for the ECM to go inactive again.

Initially on my H3 for instance, if I were to remove the pos battery clamp from the battery, and then hook my multimeter leads between the two connectors (using the 10A plug on yer meter), the initial reading will be ~3.5A for about a minute or so. Then the amperage will drop down to .84A and stay there for about 25-30 minutes. That's too high. I forgot about the 'sleep' mode wait ..till I remembered. Then after a prolonged state of inactivity, the ECM will will go to sleep (I know that's not the technical term) and the base current drain drops down to .028A on mine. Which is in the normal range of parasitic draw. Pulling fuses to find a drain kicks it back up into the .84A range FYI. So it would be better to probably backprobe fuses if you can.

The point is, to get an accurate measurement of base parasitic draw you need to wait a bit. If your multimeter has auto-off, you might want to put APO (Auto Power Off -- or whatever your meter's auto-off term is) ..turn that feature 'off' or 'APO Hold' for this test.

Anyway ...I know this was discussed a long time ago, but it's often overlooked and, hopefully, a good reminder. (I forgot about it at first ..he he).

Cheers!!

 

[Bowser-II]

So did you find the issue?


Sent from my iPhone using Tapatalk

 

[Jeepwalker]

It looks like a battery failing early. Parts store confirmed high internal resistance, lower CCA.

I 'thought' I was reading high drain. Started checking fuses ..then I remembered ya gotta wait for the computer to go 'inactive'.

I'm going to continue watching things just in case. Charging ..everything else seems fine. Cable connections good.

 

[650Hawk]

Hey all. Had to track down a recent battery issue and look for a short. Just wanted to remind H3 owners trying to track down a draw or short to keep this one bit of info in mind:

After you unhook your battery cable and get your multi-meter leads secured to the battery terminal and the battery clamp, you need to leave your meter sit undisturbed (key off, doors closed) for about 30 minutes for the ECM to go into 'sleep' mode. Once it goes into 'sleep mode', or it's lowest inactive state, the amp draw should go to it's base level and you can then observe the base battery draw.

A method of getting around this wait is if the vehicle has been sitting for a while (the hood up--i.e. ECM is 'inactive'), a person could put a test probe on the battery post, tape or secure the other probe to the battery clamp, and carefully lift the clamp off the post while keeping connection with the test probes. View the amp reading, then gently replace the battery terminal clamp. If the meter probes slip, the ECM will suddenly wake up and go to a higher amp draw state (~.84-ish) and you'll have to wait for the ECM to go inactive again.

Initially on my H3 for instance, if I were to remove the pos battery clamp from the battery, and then hook my multimeter leads between the two connectors (using the 10A plug on yer meter), the initial reading will be ~3.5A for about a minute or so. Then the amperage will drop down to .84A and stay there for about 25-30 minutes. That's too high. I forgot about the 'sleep' mode wait ..till I remembered. Then after a prolonged state of inactivity, the ECM will will go to sleep (I know that's not the technical term) and the base current drain drops down to .028A on mine. Which is in the normal range of parasitic draw. Pulling fuses to find a drain kicks it back up into the .84A range FYI. So it would be better to probably backprobe fuses if you can.

The point is, to get an accurate measurement of base parasitic draw you need to wait a bit. If your multimeter has auto-off, you might want to put APO (Auto Power Off -- or whatever your meter's auto-off term is) ..turn that feature 'off' or 'APO Hold' for this test.

Anyway ...I know this was discussed a long time ago, but it's often overlooked and, hopefully, a good reminder. (I forgot about it at first ..he he).

Cheers!!

Excellent info/reminder. Sometimes electrical issues are a royal pain, particularly parasitic draws or ground issues, and especially on a vehicle that is so sensitive to voltage variations like these H3s are.