R1200C Dead Battery

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R1200C Dead Battery

Postby ConceptsES » Sat Dec 20, 2003 11:24 pm

I picked up a used R1200C a few months ago and vowed to start it over the winter to keep the battery from going dead. However, the cold has taken its toll, and although the battery isn't dead yet - it's not charged enough to start the bike. From what I understand the gas tank has to be removed to get to the battery - I'm not very mechanically inclined and not crazy about taking the gas tank off. I figure there must be battery leads somewhere that I can connect a charger to? I haven't found anything. Any ideas? Or tips on maintaining a motorcycle in the winter (this is my first bike)? Thanks!
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Same Problem

Postby Banshee » Sun Dec 21, 2003 2:20 pm

My husband's 2003 F650GS is having the same problem. It's actually been a problem since he's had it, even during the summer. There is still juice because the lights will come on but not enough to start the bike. Now that it's winter it's evey time he goes to start it no dice. We had Morton's (where he got it) take a look at it a few months ago, but apparently it started right up every time (of course). I think Morton's thought we were nuts. So now my husband has to jump the battery every time he wants to ride.

Should he just buy a new battery?

My '03 F650CS starts right up every time --makes me feel guilty.
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Postby Anton » Sun Dec 21, 2003 3:49 pm

Basically, any BMW can be charged through the accessory socket. In fact, just about any BMW charger you buy will have the plug for that, and most others can be ordered with the "BMW Plug" which is really a DIN standard, not BMW.

The only thing to watch out for is that the newest bikes have the "BMW Gel Battery" and BMW wants you to charge them with the "gel only" charger.

Any dealer can get you hooked up with what you need, or you can buy a charger from Rider Warehouse, buy a BatteryTender, whatever. If the vendor doesn't offer the BMW plug with it, you can get the plug from the dealer for about ten bucks. Wire it so that the center contact is positive and the outer ring is negative.
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Postby Anton » Sun Dec 21, 2003 4:06 pm

Banshee, if that F650 needs jump-starting after only a few weeks, something's wrong. If it's under warranty, get it taken care of. If not (or if you want to troubleshoot it anyway) do this:

Before riding - before starting the engine - measure the battery voltage. Should be in the 12.6 to 12.8 range, for the old-type batteries and maybe around 13.0 to 13.1 for the gel ones. If it's much below that, the battery is either bad or else it's not getting recharged when the bike's running.

While the bike is running - easiest if you rig a voltmeter to look at while riding - monitor the voltage with the engine well above idle. It should go up to about 14V I think, definitely above 13.7 or so. I'm not sure about the F650 specifically but the Ks and Oilheads are 14. If it's not close, you probably have a charging problem.

Lastly, measure the battery voltage immediately after riding and then after a few days or weeks of non-use (if that ever happens) or at least right before riding again. Some drop is normal, but if it drops more than 0.2V, maybe 0.3V, the battery might be bad.

If, after standing for a long time, the battery voltage is still good and high but won't turn the engine over when thumb the starter, the battery is bad, simple as that.

So to sum it up... there's a good "standing voltage" for the battery, a good charging voltage for the bike, and then an acceptable voltage drop after riding. Find out what differs from that I describe, and you will know the problem.
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Thanks

Postby Banshee » Tue Dec 30, 2003 9:48 pm

Thank you for the advice Anton. My husband has contacted Morton's and they'll hook him up.
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