Canbus Voltage

[Hexme]

Hi Guys,

Just made myself a lead to connect my satnav to my headstock power supply. The satnav won't power up..... On checking the voltage from the headstock with a voltmeter its barely reading 7 volts, I thought it was supposed to be 12 volts, any ideas?

Thanks

 

[Kremmen]

What are you measuring the voltage with? If all you have connected is a normal high input impedance Digital Volt Meter, then it is likely that the voltage you are seeing is an illusion.

With only a DVM connected, even a few micro amps leakage into the wiring from ZFE will cause this voltmeter reading.

Put a 10K or 22K resistor across terminals 1 and 3 (to bleed off any small leakage current), then measure the voltage. I'll bet that your reading is now zero.

The ZFE that switches on and off the current to your wiring, does so electronically. In the "off" state, there is a tiny leakage current still flowing of a few micro-amps. This is utterly insignificant.... for example, a leakage of 10 micro amps would take 2 million hours to discharge a 20 A-H battery, yet this tiny amount of current when fed to a typical DVM (that has a 10 meg ohm input impedance) will still result in a reading of several volts.

I would first suggest you purchase a can bus cable/connector from BM

 

[Engineer]

+1

 

[Hexme]

Thanks Kremmen,

I did purchase the purpose made canbus connector from Nippy Normans to splice into my Garmin 660 cable. I've been using a digital AVO to check the voltage as yet have still had no joy. Might have to sleep on it and try again tomorrow.

Thanks again for your help.

 

[gncpr67]

Ive got the same problem with my canbus plug/Zumo! must be a simple reason but still no idea why it will not power/charge the Sat nav Sat Nav still wired direct to battery and works fine but would still prefer the option wiring via canbus plug... A bmw sourced plug as well!!! any help would be appreciated.. taa

 

[Hexme]

Ive got the same problem with my canbus plug/Zumo! must be a simple reason but still no idea why it will not power/charge the Sat nav Sat Nav still wired direct to battery and works fine but would still prefer the option wiring via canbus plug... A bmw sourced plug as well!!! any help would be appreciated.. taa

Yep, tried the same but as soon as I connect it to the canbus there doesn't seem to be enough juice to power it up

 

[walrus]

All I can say is that after a bit of dithering I got round to it last weekend. BMW supplied plug - 40 mins ham fisted soldering and fumbling and it worked first time. Hardest bit was finding the bloody canbus socket. (09 1200GS)

 

[Hexme]

Spent a couple of hours after work today, now I'm very confused. If I plug the canbus lead into the socket without anything attached it reads 12v, as soon as I connect the spliced lead to it, it reduces to 5 or 6 volts?

 

[st247]

Just a thought, but if you've got a short circuit in the lead the controller will shut down the circuit as soon as you connect it. Might be worth testing the resistance between the wires in your lead to rule it out.

 

[walrus]

Just another thought, did you cut the inline fuse out of the Garmin lead? I did.

 

[Hexme]

Just another thought, did you cut the inline fuse out of the Garmin lead? I did.

Yes i did.

 

[Hexme]

Just a thought, but if you've got a short circuit in the lead the controller will shut down the circuit as soon as you connect it. Might be worth testing the resistance between the wires in your lead to rule it out.

Good idea ill try that next.

thanks

 

[Grey Beard]

Are you sure you connected the correct two yellow leads from the BMW plug to the Garmin and also that they are the correct polarity? There are three leads (don't use the pulse lead).

Did you use shrink wrap over the two solder connections to prevent a short?

http://www.motorcycleinfo.co.uk/index.cfm?fa=contentGeneric.nvxszdkebklxuaer&pageId=167512

The CAN-Bus is 5A maximum, so if there are any wiring faults causing a higher current draw, the CAN-Bus will shut it down until reset with ignition switch. (I had problems connecting in a charger unit for a Dell Laptop until I realised that the Laptop charger drew 90W equivalent to 7.5A ). You could try connecting an ammeter in series, if possible, to see if current overload is the problem, though the CAN-Bus will shut down pretty quickly.

I connected a Zumo 660 to the CAN-Bus headstock socket recently. No problems once I had located the BMW socket behind the oil cooler on the 1200GSA.

Grey Beard

 

[Roadman]

Had a mate with a 2010 gsa with exactly the same problem, i.e. not enough power from the cabus socket to power the Zumo. We were reading about 12 volts at the canbus socket compared to 12.5 volts at the auxiliary power socket. We connected a 2w test bulb to the canbus socket and there was barely enough power to light the filament. Basically we were getting volts but very little current. After much discussion and testing by us and the dealer, it was determined that the ZFE was faulty. They replaced it under warranty and it has indeed cured the problem. I will add however, that the dealers seem to be reluctant to admit to a faulty ZFE.

Maybe worth discussing with your dealer as I have also heard of another ZFE being replaced for the same reason.

 

[Hexme]

Thanks Roadman,

I'm picking up my new bike today so I'll try it again on that, if it works it was a faulty ZFE, if it doesn't it was a faulty "me" for getting it wrong somewhere

 

[Rick 1600]

I did a post on this a few weeks ago. My Zumo wouldnt fire up when plugged into the socket between headstock. Only 11.5v coming out.

The problem was the control box under the tank. Runs all kinds of electrical do da's. Its £400 to replace, mine was done on warranty.