Battery drain

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

I seem to have quite a bit of parasitic draw on my system when parked. If I leave it for a few days it’s weak and a few more days it will be dead. I think it’s around 5 amp draw! I have an alarm system but even when unarmed it seems to draw. Any ideas? I dunno how to diagnose it.

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

Jett wrote:

I seem to have quite a bit of parasitic draw on my system when parked. If I leave it for a few days it’s weak and a few more days it will be dead. I think it’s around 5 amp draw! I have an alarm system but even when unarmed it seems to draw. Any ideas? I dunno how to diagnose it.

Pull fuses one by one until the problem goes away. This will at least give you some idea of which circuit(s) to investigate.

Start with stuff that's secondary to operation - radio, defroster, cabin fan, interior lights, heated seats, etc.

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

casm wrote:

Jett wrote:

I seem to have quite a bit of parasitic draw on my system when parked. If I leave it for a few days it’s weak and a few more days it will be dead. I think it’s around 5 amp draw! I have an alarm system but even when unarmed it seems to draw. Any ideas? I dunno how to diagnose it.

Pull fuses one by one until the problem goes away. This will at least give you some idea of which circuit(s) to investigate.

Start with stuff that's secondary to operation - radio, defroster, cabin fan, interior lights, heated seats, etc.

Good idea. Thanks.

WWDiesel · **Posted:** Mon Jun 15, 2020 3:54 pm

Old mechanics trick,
Disconnect battery negative cable.
Wire in series between the negative battery post and the disconnected battery cable a 12v light bulb like a 1156 or similar. (Taillight, turn signal bulb, ect.)
or, if you have a good multi tester, put the +wire and the rotary selector switch in the 10A position, and wire it in series between the battery - post and cable to read actual amp current draw.
If you have a drain, the light bulb will light up real bright if you have a full 12v drain. Or meter will show actual amp drain.
Then pull each of the fuses one at a time until the light bulb goes out or goes down to a very dim glow.
I would start with the fuses in the fuse panel on the left side of the dash. If not found there, they go to the fuses under the hood.
Normal draw on a battery should be less than 0.05 or less. lower is better... :wink:

TKB4 · **Posted:** Mon Jun 15, 2020 4:00 pm

There are some good videos on you tube on how to do this . The above is a good start. You will probably find several very small drains that are not the main culprit like the LED display lights on a radio etc. A small amount of draw is considered normal I think its around 200 ma or less. Generally use multimeter to measure amps drawn to connect battery post to removed battery cable. Here is one of the videos:

https://www.youtube.com/watch?v=KF1gijj03_0&t=120s

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

Yes I expect a drain but this seems to be several amps. I have a good meter I can do direct wired amp meter to 60a and clamp meter to 600a.

WWDiesel · **Posted:** Mon Jun 15, 2020 11:10 pm

Jett wrote:

Yes I expect a drain but this seems to be several amps. I have a good meter I can do direct wired amp meter to 60a and clamp meter to 600a.

A abnormal parasitic draw will more than likely be much less than 10 amps. More likely in the 1 to 4 amps draw neighborhood based on your description of how long it takes to kill the battery.
You will find it will not be that much, but time and a very low amp draw will kill a battery given enough time.....
I have seen a 0.5a draw kill a battery if the vehicle sets for over a few days...
I once had a customer who had a Dodge diesel which has two huge batteries and they were going dead if he let it set for over a week or more.
Turns out, he had a Garmon GPS connected to the power plug and he was leaving it plugged in all the time and it was pulling his batteries down. :shock:

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

Probably the big touchscreen stereo it has.

SargeIndustries · **Posted:** Tue Jun 16, 2020 8:08 am

Do you have a factory towing harness installed? If you do, try accessing it behind right rear interior panel. One of the relays may be warm. I believe its the one responsible for charging trailer. Pull relay and see if problem goes away. This was my battery drain problem.

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

SargeIndustries wrote:

Do you have a factory towing harness installed? If you do, try accessing it behind right rear interior panel. One of the relays may be warm. I believe its the one responsible for charging trailer. Pull relay and see if problem goes away. This was my battery drain problem.

I do have factory towing. Can you elaborate on which panel this is behind? Rear right like the very back cargo area? That panel easy to remove

SargeIndustries · **Posted:** Mon Jun 22, 2020 11:49 am

as you are facing toward the front of the vehicle with the rear gate open, the panel on the right above the right rear wheel. It a pretty big panel. May not have to remove the whole thing. The wiring harness will be laying on top or nearby the wheel well. That is where it was on mine. It is will have a lot of black cloth tape that will have to be unwrapped to get to the relays.

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

Awesome thanks. That’s what I thought you were suggesting but I was surprised they would put serviceable electrical in there and didn’t want to do all the work to pull that angel if it wasn’t the right spot. I’ll check it out today.

Battery drain

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