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Got a vauxhall that drains the battery completely flat within around 3-4 days. Before it came to me it's had 3 batteries and 2 alternators, so I have checked these out and found the battery is correct for the car and the alternator is putting out over 14v when running. This leaves me to believe there is a drain but the reading on the meters I have tried is 0.004amps. I have tried my snap on vantage and snap on meter but the results are the same. I cannot get my head around that the battery is draining but very little current draw is showing. The meter is set up in series with the battery negative post and the negative cable so I do not believe I am doing anything wrong. How can a battery drain on the car with very little draw? I have tried fully charging the battery and leaving off the car for a few days and it holds it charge perfectly so that kinda rules put the battery for me. I can see the voltage on the meter dropping throughout the day when set up to measure voltage but when I set it up on amps I see very little draw. Anyone have any ideas? Thanks
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer." I have learned more by being wrong, than I have by being right.
I will have to check at work tomorrow but off the top of my head I think its around 40. I cannot figure out how to load photos on here but I am trying.
It's possible it is an intermittent load. Things like wiper motors (usually rear wipers) will periodically try to park and draw ~5A for short periods. Various modules and wake up and create large current draws as well. If you can put a scope on it with a very slow sweep you might catch something. If no scope, try putting a 1A fuse inline with the negative cable and leave it sit over night. If the fuse is blown the next day, you've got an intermittent load.
I'm not familiar with this vehicle, but, if it has a 'smart key' near by that might be waking it up as well.
Corrosion or acid seepage on the top of the battery can create a path for voltage to flow and eventually discharge a battery.
Not the most likey issue, but something to tuck in your hat.
Thanks for the replies and help. I have attached a test lamp in series with the battery ground and ground cable instead of the meter and I have a faint glow from the light. Disconnecting the BCM puts out the light. There are some fuses on the BCM, removing all of these does not put the light out. Not until I disconnect all the multplugs on the BCM does the lamp go out. Unfortunately I do not have any plug pin out info so I cannot confirm if it is the BCM so it may have to go to main dealer where they should have that info.
If you have ScannerDanner premium, watch Parasitic Draw testing a GMC Sierra. Paul will explain why the test light procedure you're using does not work.
"an open mind let's knowledge flow in and wisdom flow out for a man who has neither never listens to those who have both".
Being wrong doesn't bother me, it's being right and not understanding why that does
If you have ScannerDanner premium, watch Parasitic Draw testing a GMC Sierra. Paul will explain why the test light procedure you're using does not work.
Intermittent spikes in power drains won't show on a multimeter.best thing to use is a scope or graphing multimeter with amp clamp. Let it record till it shows a spike or set up a trigger to capture it when it happens.
The BCM could take a long time to go to sleep too. Connecting and reconnecting may also be waking it up. I find that when I have a couple hundred mA draw, I make sure to wait longer to let the BCM go out. If it uses a natural vacuum EVAP test, that monitor could take hours to complete too.
Also check for any aftermarket installs under the dash.
Good chance of an intermittent here. I've see cars turn the stereo after they've been sitting. Just a matter of catching the culprit the act.
