BMW's Battery Charger for Their New Bikes

[David]

 

If you plan to buy the new RT, you might as well start saving your shekels for the super duper charger. In spite of it's smaller footprint, it's a whopping $106.

 

And from Service Bulletin 612 004 04 (039)

 

The battery cannot be charged using the On Board Socket if the battery has less than 7V, as the 'automatic switch on' function control unit is unable to operate in this voltage range.

 

And elsewhere:

 

The charger and its connection with the On-Board Socket is not short-circuit proof, so it is important to follow exactly the points noted below.

 

So the sequence is as follows:

 

1) turn key on

2) connect charger to bike

3) connect charger to outlet

4) turn key off

5) sleep well knowing you've done the german rain dance

[Marty Hill]

Or you could pay $84 at chi-bmw.

[Joe Frickin' Friday]

What does this charger do to earn its keep? Why couldn't I use a Battery Tender or something else, and plumb it straight to the battery?

[David]

What does this charger do to earn its keep? Why couldn't I use a Battery Tender or something else, and plumb it straight to the battery?

 

You could except that would violate another precious German principle that specifies that the battery not be hooked up to the fancy dancy electrical system while being charged...unless you use this charger.

[Firepole]

I'm not quite sure what the charger is supposed to do. I've had bkes for about 15 years and never had a battery that couldn't start a bike. My rule of thumb has proved itself over the years.

"ride at least one tankful of gas per month"

 

That was harder years ago while living in Chicago, riding a Sportster, and no heated gear.

 

No I live in Balmy New Jersey and wear heated gear. I ride every week alternating bikes so the longest one of the 2 bikes goes is 2 weeks. So when does the charger thing get hooked up?

[space]

According to the dealer here (Morton's), BMW won't be selling that one any more. When Beck and I switched over to '04's we bought the BMW charger that looks just like a Battery Tender.

 

It looks like Deltran is making a do it all Battery Tender that specifically states Gel batteries on it and is only sold under the BMW logo. It was also much cheaper than the original BMW one (around $70ish).

 

[David]

Phil, does this one have the technology to bypass the cutoff on the 12GS, for example? More specifically, the accessory socket remains hot for a few minutes after the ignition is switched off. The battery charger I listed above interfaces with the CPU to bypass that feature. Otherwise the connection to the battery is dead.

[space]

Phil, does this one have the technology to bypass the cutoff on the 12GS, for example? More specifically, the accessory socket remains hot for a few minutes after the ignition is switched off. The battery charger I listed above interfaces with the CPU to bypass that feature. Otherwise the connection to the battery is dead.

 

Nope. I tried to buy the BMW charger a couple weeks ago and was told that they didn't have any more and weren't going to be getting any more in.

 

To use this one on the new GS you would have to connect the pigtail to the battery directly, which I must say does suck.

[steveknapp]

It's not even able to plug into 240V. What crap.

 

David, I'm a sick bastard. I'm curious what exactly they are doing to interface the charger to something else. If I'm still making it to El Paeso (did I say that?), could you bring this along and I could lurk in a dark corner with it, your bike, and my o-scope?

[David]

Be glad to bring it. I'm buying Cracker Barrel stock now.

[Tool Man]

David,

 

Ok now I'm wayyyy confused.

 

I actually have two of the BMW tenders for each bike. I usually keep it plugged in when I know I'm not going to be riding. I get what your saying about the acces. socket power issue. However, I did commit a brain malfunction and forgot to plug in the BMW Tender during the month of August. Battery went dead to the world....no problem...plugged in the tender and it was up and running by next morning. If I read your comment correctly the acess. socket needs to be up to 7volts before the tender works? My key was definately turned off when I plugged it in where you say it needs to be turned on, plug in the tender, then turn key off. Since I didn't do the "rain dance" just ever so while baying at the moon and my left foot in steer s^^t why then did my tender charge a completely dead battery over night

 

Please enlighten me on this or was I just an isolated case?

 

Mike W.

[David]

Mike, that note about the 7v was meant to apply only to the new BMW lines, starting with the R12GS. I presume that the new K12S will be exactly the same, though. None of the other bikes in their line-up power the accessory socket momentarily at shut down and then cut power to it.

[Johannes]

I am confused with the BMW charger.....I have the BMW charger which David shows in the picture, and would like to have advice from users. Most of the time, the charger works as it mentioned at the manual, but today I found the 0-1/3 LED (red) lit together with the 3/3 LED (green), what would be the possible casue? is it at de-sulphating? (manual said de-sulphation should be 0-1/3 LED blinks........) and what activates the charger to de-sulphating mode?