[Ron ///Man]

Newbie to the diesel world here. I'm wondering if anyone can tell me the typical parasitic draw on a battery when the car is not running and is 'asleep'. On my recently acquired 335d which has a new factory battery, my BatteryTender 1.5A trickle charger(s) will never fully charge the battery and go into 'float' state where it just monitors the charge. I tried two of the BatteryTenders, and I also tried a larger / older 2A trickle charger, and no go on any. This is after 2-3 days of charging, and, the battery was not dead, and the car had been run for over an hour at highway speed. I'm thinking the parasitic draw on the battery has to be greater than 2A since the charger never catches up. Every other vehicle I use the trickle charger on usually is fully charged and floats after less than 24 hours. Anyone have any data?

Thx,
Ron

[M5_1of400]

Originally Posted by Ron ///Man

Newbie to the diesel world here. I'm wondering if anyone can tell me the typical parasitic draw on a battery when the car is not running and is 'asleep'. On my recently acquired 335d which has a new factory battery, my BatteryTender 1.5A trickle charger(s) will never fully charge the battery and go into 'float' state where it just monitors the charge. I tried two of the BatteryTenders, and I also tried a larger / older 2A trickle charger, and no go on any. This is after 2-3 days of charging, and, the battery was not dead, and the car had been run for over an hour at highway speed. I'm thinking the parasitic draw on the battery has to be greater than 2A since the charger never catches up. Every other vehicle I use the trickle charger on usually is fully charged and floats after less than 24 hours. Anyone have any data?

Thx,
Ron

I believe this is a common issue with people that have Confort access in their cars, IIRC it got something to do with faulty/defective door handles.

[RL18]

Originally Posted by DieselDemonDM

I believe this is a common issue with people that have Comfort access in their cars, IIRC it got something to do with faulty/defective door handles.

Agree with this ^ You can pull the fuse for this and see if the problem goes away.

Another issue could be the alarm siren. If the battery within it starts to degrade it will pull from the main battery.

Do you have any bmw scan tools? You can request a "shutdown mode" which will force everything to power down.

That's a place to start. Chasing electrical draws is very tricky in these cars. I had one in my x5d, it was so bad that one night in the cold Maine weather and the battery would be completely dead. Took out the frm module. Turned out to be a pinched roof drain hose on the rear passenger side, it was like this since it was built!!! I had 4" of water in my trunk on one of the side cubbies sloshing around getting water all over connectors and my battery. Replaced the drain hose and the connectors on the TCM and bam draw was eliminated.

Oh and I use a CTEK charger for my x5 and 335d. Ive brought some batteries back from the dead with this thing, it's a very nice thing to have.

[Ron ///Man]

Originally Posted by DieselDemonDM

I believe this is a common issue with people that have Confort access in their cars, IIRC it got something to do with faulty/defective door handles.

Thx, I'll start with that one, and do a little research on what the fix is if they are the problem.

Originally Posted by RL18

Agree with this ^ You can pull the fuse for this and see if the problem goes away.

Another issue could be the alarm siren. If the battery within it starts to degrade it will pull from the main battery.

Do you have any bmw scan tools? You can request a "shutdown mode" which will force everything to power down.

That's a place to start. Chasing electrical draws is very tricky in these cars. I had one in my x5d, it was so bad that one night in the cold Maine weather and the battery would be completely dead. Took out the frm module. Turned out to be a pinched roof drain hose on the rear passenger side, it was like this since it was built!!! I had 4" of water in my trunk on one of the side cubbies sloshing around getting water all over connectors and my battery. Replaced the drain hose and the connectors on the TCM and bam draw was eliminated.

Oh and I use a CTEK charger for my x5 and 335d. Ive brought some batteries back from the dead with this thing, it's a very nice thing to have.

Thx for the input! I recall the service manager at my dealership mentioning issues with shutdown on some models... I don't have a scan tool like Inpa or anything like that, just a hand held code reader. It's high time that I got an appropriate code reader setup and started nosing around in there... I did just get a 4A trickle charger so I'll see if that does it. The thing is, the battery does not go dead, even after sitting for like a week. I think I'll borrow a friends clamp on amp meter and measure the parasitic load, and then pull the fuse for the door handles and see if it drops. I didn't know the alarm had it's own battery. That seems kind of short-sighted on BMW's part...

Quite the dilemma on your X5d! I hope this isn't anything as involved as that, but now you have me wondering if I should go check my X5d drains!!!

[RL18]

Originally Posted by Ron ///Man

Thx for the input! I recall the service manager at my dealership mentioning issues with shutdown on some models... I don't have a scan tool like Inpa or anything like that, just a hand held code reader. It's high time that I got an appropriate code reader setup and started nosing around in there... I did just get a 4A trickle charger so I'll see if that does it. The thing is, the battery does not go dead, even after sitting for like a week. I think I'll borrow a friends clamp on amp meter and measure the parasitic load, and then pull the fuse for the door handles and see if it drops. I didn't know the alarm had it's own battery. That seems kind of short-sighted on BMW's part...

Quite the dilemma on your X5d! I hope this isn't anything as involved as that, but now you have me wondering if I should go check my X5d drains!!!

My x5d was something like 400milliamps power draw from the tcm. I just had a connector shorting out from water damage. It could be as simple as updating all your modules too. I know these cars pull a very small amount of current even when off but it's not a lot.

Checking your roof drains isn't a bad idea. I'm not sure if anything changed in the roof drain design from my e70 to your f15, but you just shoot compressed air through them. They really shouldn't clog but things can get stuck in there sometimes, especially if you have it open a lot. My x5 wasn't clogged though the hose was pinched between some wiring from whoever initially ran the line for the drain hose. Pretty simple fix though

[_N54]

I use this tool at work to check for parasitic drain on each fuse... it works pretty good and saves a ton of time if you do come across something you can't find quickly: