BMW Charger

I have a BMW charger which I use via the dash socket. Problem is when it goes into ''sleep'' mode I don't get the impression its doing its job. Example last year - 6 months on the charger - battery dead. Replaced the battery. Last August was my last ride so again on the charger over winter. Tried to start the bike over Christmas and no juice. Unplugged it and put it back on the charger and in 10 mins all OK.
I have modified the charge cable a bit. I added a 3 metre section between the charger and the plug that fits onto the bike.
Could this be a problem or is my charger simply not charging when it goes to sleep?

Adding length will not stop your charger working. Im sure the canbus shuts down the socket after a few minutes of the ignition being switched off. Best thing to do is fit a fly lead direct to the battery and plug straight in. Sorted

Is it a trickle charger or a battery maintainer?

The first will just charge the battery and if it goes to sleep it might not do its job anymore where a battery maintainer will allow a small discharge and top it up in pulses but never get the battery to 100%.

Cheap battery maintainers to be had online, doesn't matter if it's not Beemer branded.

Not from i but this is what you must do normally.

I also have a BMW Battery Charger and use it on my 2015 R1200RT. I plug in directly into the onboard power port to maintain the battery. However, the charger and bike need to "talk to each other" to make sure the bike knows the charger is connected.

Here's the 3-step procedure.

1. Turn the ignition of the motorcycle to "ON." (Do not start)
2. Connect the battery charger to the "On Board Socket" first, then connect the charger to the 220 volt outlet.
3. Turn the ignition key to the "OFF" position.

thanks for this Winjar. Also referring to Delboy777 this seems to be logical. my guess as well is the canbus turns off the power to the charger socket. I'll give it a try!
thanks
By the way, Winjar, you in AMS?

Winjar said:

Not from i but this is what you must do normally.

I also have a BMW Battery Charger and use it on my 2015 R1200RT. I plug in directly into the onboard power port to maintain the battery. However, the charger and bike need to "talk to each other" to make sure the bike knows the charger is connected.

Here's the 3-step procedure.

1. Turn the ignition of the motorcycle to "ON." (Do not start)
2. Connect the battery charger to the "On Board Socket" first, then connect the charger to the 220 volt outlet.
3. Turn the ignition key to the "OFF" position.

Click to expand...

The BMW charger is programmed to recharge the battery when first connected. After the battery is regarded fully charged, the charger shuts down, and an internal timer starts to run. After a given time. the timer wakes up the charger, and the charger sends a puls into the socket that wakes up the port for the AUX plug and allows for the charger to read the condition of the battery and recharge as needed.

However, the AUX port is controlled by a onboard computer. If the computer suspect any unauthorized current draw, it shuts of the AUX port, and there will be no charging.

This Unauthorized draw may be some extra equipment mounted by the rider, or some times there seem to be no sensible explanation to why it shuts down.

The port should open up without any outside action. Some times it does, some times it don't.

However, experience have shown that even if it's a brilliant idea from BMW, most people find it an even better idea to not trust it and hook up the charger directly to the battery. (Most people in this context may include BMW dealers)

grantmac said:

thanks for this Winjar. Also referring to Delboy777 this seems to be logical. my guess as well is the canbus turns off the power to the charger socket. I'll give it a try!
thanks
By the way, Winjar, you in AMS?

Click to expand...

Yes but lot of time travel in Europe for work, you are welcome, if I have 1 month home I happy.