BMW Battery Charger Error with Switched Accessory

[websterize]

An error light illuminates steady red on my BMW battery charger (PN 71607688865) after about 15 minutes of charging. I know what causes the light to illuminate but am not sure why.

The problem started after I installed a GPS receiver to the switched-accessory outlet under the gas tank. The install appears ok, as the GPS powers on and off with the ignition key. Furthermore, I motored 200 miles yesterday, and the bike powered the GPS the entire trip.

Before the install the charger would progress from 0/1 (red), 1/3 (yellow), 2/3 (yellow) to 3/3 (green) as it charged the bike's battery. With the GPS plugged in, however, it charges to 2/3, then drops to 1/3, then the four progress LEDs go dark. Then only the power and error lights illuminate on the charger. When I unplug the GPS power cord from the switched connector under the tank, the charger finishes to 3/3 (green) as it has since purchase.

So I know the what of the problem but not the why. Short circuit? Firmware? Any ideas?

[hjsbmw]

So I know the what of the problem but not the why. Short circuit? Firmware? Any ideas?

My idea would be that the GPS goes into a standby mode when plugging it in, which means it draws some current. Those chargers have sensitive circuits, and it could be that the GPS's current draw causes your charger to think that the battery is not capable of holding the charge.
The last stage of your charger is probably a float stage, which means the charger switches to a low current after the battery is full, just to maintain the charge. Smart chargers detect the 'full' state by shutting down all current to the battery for an amount of time, monitoring the voltage. If the latter stays constant the battery is considered full. Having a user on, such as your GPS, will make that test fail, and the charger goes back to stage 2 where it attempts to bring the battery to a full charge.

If you have a multimeter, see if there is a voltage drop when you plug in the GPS unit. I suppose there could still be another problem, but you asked for ideas.

[websterize]

That's an interesting idea about the multimeter. I've plugged in the battery charger with the GPS mounted in the cradle and with no GPS in the cradle, and the error light illuminates on the battery charger in both configurations after about 15 minutes. With nothing plugged in, it seems odd for the cradle to draw power from that accessory plug under the gas tank.

I'm having some work done on a tire at the dealer tomorrow. I'll take in the battery charger in the hope of replicating the problem. Maybe they can advise.

[websterize]

I visited the LBS today for some tire work and to ask about the battery charger's error light. I brought the charger, hoping I could replicate the problem, and they could plug in a diagnostic computer, read a fault code and give some advice. Unfortunately, a helpful tech said, a battery-charger error wouldn't show up on their diagnostic tools. Many accessories, such as heated liners and others, cut out unexpectedly via CAN-BUS power. He suggested bypassing with a Powerlet, e.g. connecting direct to battery. Otherwise, he said, I need to unplug the GPS cradle from the bike's GPS socket to fully charge the battery.

(Also asked how often I need to charge the battery. The tech and a service advisor asked how often and far I ride. I commute almost daily, and roundtrip is about 20 miles and take long rides on weekends. (At first the tech thought I said 20 miles each way on the commute, and said "perfect.") Both agreed that the bike gets most of its power from the battery the first 20 miles. After a few days of this, with no charging, they said the battery would get low. They suggested charging every few days or taking the long, windy way home. Probably common knowledge to many of you . . . but news to me.

BMW announced the zumo 660 Motorrad Navigator IV, scheduled for third quarter. Figures they'd do that a few days after I bought one. If the Motorrad mount isn't too expensive, I'll see if it plays nice with the charger.

[deilenberger]

Bill,

My daily commute is 17 miles each way. Been doing it now for 2 years - still on original battery. I've never connected my bike to a charger. I frequently run my Hella FF50 driving lights going and coming (sun behind me each way..) so that adds another 110W to the bike load.

I think battery charging as maintenance is vastly overdone.. Ride it. If it complains then figure out why.

[simonwheeler]

Bill,
I have the same problem with my autocom unit. I have been advised to insert a removable fuse on the power lead (which is connected to the power outlet below seat) to the autocom unit, which acts as switch. So I disconnect the autocom unit when using the charger.
Simon

[hammick]

I use a relay for my Sargent Heated seat on my '07 R1200GSA. My charger also goes into error mode. It has worked fine on a stock K1200GT and stock R1200R. The relay is powered by the accessory plug, so it doesn't power off immediately.

Never had a clue why until I was getting this error until I read this post.

[websterize]

BMW announced the zumo 660 Motorrad Navigator IV, scheduled for third quarter. Figures they'd do that a few days after I bought one. If the Motorrad mount isn't too expensive, I'll see if it plays nice with the charger.

I installed the Navigator IV last night, and it works fine with my battery charger — no error lamps.

Wanted to buy only the Nav IV cradle mount, but apparently that isn't possible. Mark, of the Chicago BMW parts department, said he did not have a part number for just the cradle. To get the BMW mount you need to buy the package. A local dealer confirmed. (I buy all my BMW farkle from Mark because of the 20-percent discount.)

Initially, I purchased the zumo 660 from garmin.com with the AMA discount. Garmin said I was over the 45-day return window but that they would authorize an RMA. I was surprised. That's a long time for a return, but I figured I'm buying another Garmin product, so what do they care. Had they not accepted the return, I would have lived with the error.

So far, so good with the Nav IV. I was worried the head unit wouldn't appear in Mac OS X, but it does: I successfully configured files and updated software. Installing the Nav IV cradle was easy — it is wider and sits higher than the zumo mount. The hard buttons on the Nav IV cradle have a nice, cushy feel when you push them, but I'm most pleased that I now have a GPS that plays nice with CAN-BUS. Unplugging the power connector of the old mount every time I wanted to charge the battery was becoming tedious.

More impressions and pictures of the Nav IV to come.

[deilenberger]

Bill,

Unless Garmin/BMW changed the scheme - buying the cradle and hoping to use it with a standard 660 isn't gonna work. Apparently the Navigator is setup with some propietary codes interfacing it to the GPS, a standard one is ignored by the cradle. Same thing on Nav-II and Nav-III.

[websterize]

Bill,

Unless Garmin/BMW changed the scheme - buying the cradle and hoping to use it with a standard 660 isn't gonna work. Apparently the Navigator is setup with some propietary codes interfacing it to the GPS, a standard one is ignored by the cradle. Same thing on Nav-II and Nav-III.

Yes, Mark mentioned this, too. He said the cradle might power the zumo 660, but the buttons probably wouldn't work. That was another reason I didn't feel bad returning the zumo to Garmin and buying the Nav IV set.