Keeping batteries charged during winter...

woodman650 · 11-04-2009, 03:50 PM

I've never stored a car for a few months, but I'm considering it for this upcoming winter. As the 135i has 2 batteries (1 in the trunk for the electronics), I'm just wondering what kind of system I would need to keep both batteries charging? I assume some sort of trickle charger... but for 2 batteries at once? It would be nice not to buy 1 trickle chargers.

Any suggestions? Thanks

nordique14 · 11-04-2009, 04:20 PM

There is only one battery. You can connect a trickle charger to posts under the hood but that just charges the battery in the trunk.

Note you will need to clip the charger onto the posts. E46 (and prior BMWs) has power adapters (i.e. cigarette lighter sockets) that remained hot even with the power turned off. In those cars you could have plugged the charged into there. Not so on the 1-series and the new 3-series.

woodman650 · 11-04-2009, 04:23 PM

Gotcha, thanks for the input. I thought I remembered hearing my advisor tell me the car has 2 batteries for some reason. He was probably talking about something else and transitioned into battery talk. Oh well.

Tom K. · 11-05-2009, 11:47 AM

He may have meant the battery in the key fob which needs to be periodically replaced. There is a dash warning light which will tell you when (see p 27 of the '08 owner's manual).

I recommend a Battery Tender or similar charger connected to the posts in the engine compartment for long term storage.

Tom

Cordoba1 · 12-02-2009, 04:52 PM

Just start the car for 10 minutes every two weeks, move it back and forth a bit. That should keep the (modern) battery charged -- AND -- It will keep your engine seals, gaskets, and other internal parts coated in oil. If it's parked in a reasonably warm place, this should keep the car happy.

11-04-2009, 03:50 PM	#1
woodman650 Super Couper 67 Rep 577 Posts Drives: TBD Join Date: Jan 2008 Location: Mountain View, CA iTrader: (2)	Keeping batteries charged during winter... I've never stored a car for a few months, but I'm considering it for this upcoming winter. As the 135i has 2 batteries (1 in the trunk for the electronics), I'm just wondering what kind of system I would need to keep both batteries charging? I assume some sort of trickle charger... but for 2 batteries at once? It would be nice not to buy 1 trickle chargers. Any suggestions? Thanks
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11-04-2009, 04:20 PM	#2
nordique14 Major 53 Rep 1,477 Posts Drives: SGM 135i 'vert Join Date: Feb 2008 Location: Sharks Territory iTrader: (5)	There is only one battery. You can connect a trickle charger to posts under the hood but that just charges the battery in the trunk. Note you will need to clip the charger onto the posts. E46 (and prior BMWs) has power adapters (i.e. cigarette lighter sockets) that remained hot even with the power turned off. In those cars you could have plugged the charged into there. Not so on the 1-series and the new 3-series.
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11-04-2009, 04:23 PM	#3
woodman650 Super Couper 67 Rep 577 Posts Drives: TBD Join Date: Jan 2008 Location: Mountain View, CA iTrader: (2)	Gotcha, thanks for the input. I thought I remembered hearing my advisor tell me the car has 2 batteries for some reason. He was probably talking about something else and transitioned into battery talk. Oh well.
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11-05-2009, 11:47 AM	#4
Tom K. Major General 124 Rep 5,627 Posts Drives: '07 328iT, '13 Boxster Join Date: Mar 2008 Location: Maryland iTrader: (0)	He may have meant the battery in the key fob which needs to be periodically replaced. There is a dash warning light which will tell you when (see p 27 of the '08 owner's manual). I recommend a Battery Tender or similar charger connected to the posts in the engine compartment for long term storage. Tom
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12-02-2009, 04:52 PM	#5
Cordoba1 New Member 0 Rep 25 Posts Drives: 135i Join Date: Oct 2009 Location: Chicago, IL iTrader: (0)	Just start the car for 10 minutes every two weeks, move it back and forth a bit. That should keep the (modern) battery charged -- AND -- It will keep your engine seals, gaskets, and other internal parts coated in oil. If it's parked in a reasonably warm place, this should keep the car happy.
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