Battery Keeps Getting Drained!
#1
Battery Keeps Getting Drained!
Hi, this is for a 2006 911. The battery is 2 years old. I had it tested and it is in good shape. however, after the car sits for a few days it drains the battery. this is after a few days not weeks. thoughts?
#2
Rennlist Member
There can a number of reasons why you can have a drain on battery - I know it sounds silly but I would 1st check and make sure your interior lights, glove box, sun visor & trunk lights are not remaining on when you shut down the car. Once you rule out these obvious reasons I would also make sure your battery is charging from the alternator - Test battery voltage during idle and make sure it's getting a charge.
You'll have to dig deeper if it isn't these easy to test reasons but I've lost battery charge from front trunk light not turning off in my old 996 C4S. Many more mechanically educated forum members will chime in I'm sure.
You'll have to dig deeper if it isn't these easy to test reasons but I've lost battery charge from front trunk light not turning off in my old 996 C4S. Many more mechanically educated forum members will chime in I'm sure.
#4
FWIW, I plug the car in if I am not driving it for more than a few days. In my short ownership using a "Battery Tender Plus", just opening the door and illuminating the interior lights for a few minutes will trigger the charger to go from float to trickle charge. These cars seem to be super sensitive.
#5
Three Wheelin'
Do you have a bluetooth module? Do you leave your car unlocked in the garage?
These were the issues that led to my battery drain. I recently installed a bluetooth module and tapped the AUX power in the passenger footwell. This circuit stays open until the doors are locked. Once the doors are locked the car goes into a low power sleep mode.
To check for parasitic drain you need to get a multimeter. Clip it to the battery and check the volts with the car off/doors unlocked and car off/doors locked. If you see a big drop a few seconds after you lock the doors you know something is not shutting off. I think the max it should be drawing with the car off is ~.4 amp. I was drawing 2.5 amps with the car off and doors unlocked and that dropped to 0.02 amps with the doors locked.
If you find a significant drain you can then start pulling fuses one by one until you spot which one is causing the issue.
These were the issues that led to my battery drain. I recently installed a bluetooth module and tapped the AUX power in the passenger footwell. This circuit stays open until the doors are locked. Once the doors are locked the car goes into a low power sleep mode.
To check for parasitic drain you need to get a multimeter. Clip it to the battery and check the volts with the car off/doors unlocked and car off/doors locked. If you see a big drop a few seconds after you lock the doors you know something is not shutting off. I think the max it should be drawing with the car off is ~.4 amp. I was drawing 2.5 amps with the car off and doors unlocked and that dropped to 0.02 amps with the doors locked.
If you find a significant drain you can then start pulling fuses one by one until you spot which one is causing the issue.
#6
RL Community Team
Rennlist Member
Rennlist Member
FWIW, I plug the car in if I am not driving it for more than a few days. In my short ownership using a "Battery Tender Plus", just opening the door and illuminating the interior lights for a few minutes will trigger the charger to go from float to trickle charge. These cars seem to be super sensitive.
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#10
Are you locking the car or letting it sit in the garage with the doors unlocked? I used to have similar issues until someone at Coffee and Cars told me they always had battery drainage issues if they left their car unlocked. I started locking mine, even with it being in the locked garage, and I haven't had any issues since.
#11
OP has your issue been resolved?
I have a friend that has been on the dealer merry-go-round experiencing the same problem. He will check the areas already mentioned in the thread but it would be good to know if you isolated your problem area.
I have a friend that has been on the dealer merry-go-round experiencing the same problem. He will check the areas already mentioned in the thread but it would be good to know if you isolated your problem area.
#12
I leave mine unlocked and always have. I drive less than 15 miles daily. My battery is always draining. I guess I’ll lock the car now.....
#13
Parasitic battery drain is no respecter of car brands. As Groovzilla wisely pointed out, by the process of elimination, you must start with the obvious (interior lights, auxiliary devices, etc. ) and then work your way towards more invasive electronics. One way of homing into the culprit of the parasitic loss, is by removing fuses and keep data on battery drain. Also, there is a good chance the battery is faulty even if it's new.
#14
Nordschleife Master
When locked (ideally with 2 locking clicks - long hazard lights) these cars drain about 45mA or about 1Ah/day.