First CAN BUS bike - what do I need to watch out for?

[Captain Beaky]

I've noticed a few rabid warnings and comments up here about the CAN BUS system on the R1200's.

What does it really mean in day-to day use?
What can go wrong, and how can I protect against it?

I want to use a battery maintenance charger on the R1200 through the winter months.
On My R1150GS - I used to plug it into the accessory socket and get on with life - but there seem to be various warnings against this on the R12's
Advice please???

Also - if fitting extra electrical accessories, what do I need to watch out for?

Thanks,

Mike.

 

[Ragnar]

What does it really mean in day-to day use?

Absolutely nothing. Don't worry about it, carry on riding and enjoy

What can go wrong, and how can I protect against it?

I've never heard of anything actually going wrong with it, just lots of rants about how it confuses people. I certainly never experienced any kind of problem.

It's really quite simple electronics, and they've been using similar systems in cars and aircraft for years. I guess it confuses some people because it's not like a conventional circuit with a fuse box etc.

I want to use a battery maintenance charger on the R1200 through the winter months.
On My R1150GS - I used to plug it into the accessory socket and get on with life - but there seem to be various warnings against this on the R12's
Advice please???

As stated, it's not a conventional circuit so not a direct connection to the battery. Simple answer - connect directly to the battery instead of the accessory socket (unless you have the actual BMW charger - I think that tells the CAN-bus to keep the system open). I fitted an Optimate lead/plug so I don't have to remove the seat.

Also - if fitting extra electrical accessories, what do I need to watch out for?

If you do want to wire into the CAN-bus you can get a proper plug to wire up from BMW. Lots of people, including me, do this to wire their GPS into the GPS power connector near the headstock, but if you try to draw too much power the bike will shut it down on you (it takes quite a bit of draw, but maybe some aux. lights/heated waistcoats etc. would do it - same applies to the accessory socket under the seat though). You can always wire directly to the battery or use a switched fusebox (or similar) if you prefer.

Thanks,

You're welcome

Mike.

David.

 

[Captain Beaky]

Thanks for that.

I'm not in the habit of riding in all-weathers, and in the UK, several months can pass without a spell of good weather - so I am plugging the bike into the charger whenever I park it in the shed. To me, plugging the bike into a charger is a day-to-day occurrence.

I agree regarding CAN bus technology - I've been working with it for years on cars and aircraft. It's more a case of what the designers decided to do with it than the technology itself.

I've now had a chance to look at the circuit diagram (Haynes Manual arrived earlier)- I now see that the power socket runs through the central electronics unit - rather than being simply a fused circuit.

I guess that it's switched and protected against overcurrent, and needs some fancy (and expensive) charger to keep the socket live. Also, I guess that the bike will shed the electrical load when it is close to stalling (as most cars do).

OK - I'll wire the charging socket straight to the battery as on other bikes.

Shame, cos it was nice to simply plug it in on the old 1150 - might even change the power socket over so it's connected to the battery direct.

Thanks for that - I'll get out there with the spanners right now......

Cheers,

Mike.

P.S.
What does actually happen if you draw too much - does it really "Shut the bike down"?

Ta,

Mike

 

[Beemerman59]

Rather than try and fit accessories into the Canbus system I opted to fitt a seperate fusebox with 6 switched and 2 unswitched outputs. The two unswitched outputs drive an accessory socket and a USB power socket. These allow me to run a compressor, charge my intercom and use an Optimate charger without any issues and with the engine off. The switched outputs (switched from the parking light) run the other stuff I want on with the ignition such as heated clothing, GPS, spot lights, twin horns etc.

 

[Ragnar]

You've got it. The accessory sockets are indeed powered via the bus and is switched and protected from overcurrent. As I said, I think it's only the actual BMW branded charger that will instruct the bike to keep the bus live and therefore accept a charge.

I have heard of a few people rewiring the accessory socket straight to the battery, but IMHO it's far easier just to get the direct battery-attached fly-lead for your choice of charger and bring the plug to the outside world. You get to keep the accessory socket too!

P.S.
What does actually happen if you draw too much - does it really "Shut the bike down"?

Good grief no!! As far as I remember, it just shuts down power to the accessory sockets, as if a fuse had blown somewhere. Bike should continue to be operational as far as starting/riding. Remove the offending item on the bus and switch off/on and power will be fully restored.

 

[tonkatoy]

Rather than try and fit accessories into the Canbus system I opted to fitt a seperate fusebox with 6 switched and 2 unswitched outputs. The two unswitched outputs drive an accessory socket and a USB power socket. These allow me to run a compressor, charge my intercom and use an Optimate charger without any issues and with the engine off. The switched outputs (switched from the parking light) run the other stuff I want on with the ignition such as heated clothing, GPS, spot lights, twin horns etc.

+1 and my battery charger has a Hella type plug on it which just plugs straight into the unswitched accessory socket every time the bike goes in the garage. Job done

btw, before someone says you shouldn't plug a charger in every time, that's exactly what I've been doing on my Blackbird and it's still on the original battery at 12+ years old. It works for me.

 

[Captain Beaky]

There's a lot of myth and mystery around trickle chargers.

Provided you have a modern charger that is designed as a maintenance - or "float" charger as some call them - then it's much better to keep it connected whenever the bike isn't in use.
The charger automatically turns off when the battery is full, turning back on again when the voltage has dropped.

The trouble starts when you let the thing run flat - sulphation sets in, and you will never get the battery capacity back.

(Next comment made to head off all those who swear by "desulphators")
Yes, there are battery "desulphators" out there - tried em, even built my own - did sort of help - but by far, it's best to put all your energies into avoid it completely - get a float charger.

 

[Deleted account 190920001]

I don't want to be pedantic, well actually yes I do. If you have been working with it for years you will know fine well that CAN isn't an object its a network protocol. Its a means of different computers to talk to each other the same as TCP/IP is used for computers to talk over the internet. Its the ZF unit that actually has all the electronics and decides what gets turned on/off where and when.

 

[bmwbikeruk]

I had a second power socket fitted on the L/H tank panel cover near winglet of my GSA and wired directly to battery, protected with fuse so I can recharge battery in winter, inflate airbed, charge up mobile, light up small portable camping lamp and so on whilst bike is stationary with ignition key removed. Of course, I have to be careful not to drain battery too much if left unattended too long but it's more convenient than wired to CAN which can otherwise automatically (annoyingly) cut off power after a minute.

 

[wilbjr21]

I had a second power socket fitted on the L/H tank panel cover near winglet of my GSA and wired directly to battery, protected with fuse so I can recharge battery in winter, inflate airbed, charge up mobile, light up small portable camping lamp and so on whilst bike is stationary with ignition key removed. Of course, I have to be careful not to drain battery too much if left unattended too long but it's more convenient than wired to CAN which can otherwise automatically (annoyingly) cut off power after a minute.

I have the same - essential if your tyre pump takes more than 7 amps (as most do).