Looking for a switched wire (ignition on)

[bluestratos]

I want to install a relay to activate my fuse block only when the key is on. Where is a good wire to tap onto for the relay? It draws next to no power.

Thanks,
Randy

[NancysToy]

I used the lighting wire to the passenger grip control, but any circuit that runs through the load-shedding relay will work. I would suggest use of a diode in the relay feed to avoid possible CanBUS problems.

[bluestratos]

where id you pick this wire up, at the heated grip control? Also, dumb question but what is a canbus?

Thanks

Randy

[Y Rider]

where id you pick this wire up, at the heated grip control? Also, dumb question but what is a canbus?

Thanks

Randy

Controller–area network (CAN or CAN-bus) is a vehicle bus (http://en.wikipedia.org/wiki/Vehicle_bus) standard designed to allow microcontrollers (http://en.wikipedia.org/wiki/Microcontroller) and devices to communicate with each other within a vehicle without a host computer (http://en.wikipedia.org/wiki/Host_computer).

[Brevet05]

If you have an RT-S, the two guages in the dash have a light that is switched power. It's a good choice if you want to have your fuse block in the front of the RT. They're very easy to access.

[bluestratos]

Ahhhhh.. I thought it was something to do with Can Am.. hence canbus, lol....

Great idea on the lights. Should I install a diode for this circuit, I would think not but your thoughts?

Thanks a bunch.

Randy

[NancysToy]

where id you pick this wire up, at the heated grip control? Also, dumb question but what is a canbus?

Thanks

Randy
Lt. Green/Gray 18 Ga. wire running to the rear control switch.


huh?
A properly sized diode inserted in the switching lead can prevent reverse EMF flow when the relay switches off, protecting the CAN-bus from high voltage spikes. It may not be necessary on the Spyder (It is on many BMWs.), but it sure doesn't hurt. Eastern Beaver uses a 1000V 1A diode. I use their systems, so that's what I use. You may have a better suggestion.

[bluestratos]

Sorry for being so dense, but he light green/gray wire runts to the heat control or the stereo controls for the passanger?

[NancysToy]

I guess I didn't understand.

A diode across a relay coil is standard operating procedure to be sure but a diode in series with a switched wire would, IMHO simply be a 0.6+V unnecessary voltage drop.

Having said that, I think all Spyder relays have a built in diode across the coil.
Not sure why the difference in the Eastern Beaver wiring, but having a diode on the relay coil positive is not an uncommon practice for motorcycle accessories. :dontknow:

[bluestratos]

The diode makes sense for the relay and the minor voltage drop will not create a problem in this case. The main hot wire will not be affected by the diode as it comes directly off the battery. Thanks for all the input, if anyone else has tapped into the harness for a relay let me know.

Regards,

Randy

[Bob Denman]

Please slow down... I'm still trying trying to get my head around this whole cannibus thingie... :D:roflblack:

Oh... never mind...

[GeoffCee]

Also, dumb question but what is a canbus?
Thanks Randy

My take on canbus is that it is a pain in the butt for an enthusiastic owner of a bike or any other machine. BMW introduced canbus to their R1200RT oilheads in 2005 if memory serves. Simply put, instead of two wires running to each electrical component on the bike, which anybody can understand and work on themselves with the aid of a circuit diagram, the canbus system uses only one wire and the chassis for the other half of the circuit. (BMW said that having fewer wires saves weight, which is difficult to argue against). To make the canbus work there is an ECU (Electronic Control Unit), or "brain" to control the operation of the electronic components strung along the canbus single-wire system.

With canbus each component in a circuit has to be "recognised" by the ECU and if an electrical item is replaced because of damage or because it has worn out, the new one has to be "introduced" to the ECU by its code. My understanding is that until this has been done the replacement item will be ignored electrically, as though it didn't exist.

Take a real easy DIY job as an example. A two-wire non-canbus bike has its foot brake switch fall apart, which means that when the brake pedal is pressed the brake light doesn't come on. A simple enough job to put right, any fool with a basic tool kit and three brain cells could swap it out for a new item in a matter of minutes.

But on a canbus machine the dealer is the only one who can undertake the job because only he has the necessary kit to connect to the bike's ECU and program in the replacement brake switch. So a simple DIY job costing peanuts becomes an expensive operation involving a workshop, a mechanic's time, etc, plus the owner of the bike loses the satisfaction of doing some of his own maintenance on his pride and joy.

Fortunately a canbus machine can have electrical stuff added to it, such as lights, intercoms, GPS, etc. Running a couple of wires with a fuse and maybe a relay directly off the battery will provide an old-fashioned two-wire circuit for additional electrical components to work alongside, but independently of, the canbus system. So it's not all bad news! :2thumbs:

[GeoffCee]

There are a few things in your canbus analysis that I don't believe are accurate.

1. Using chassis as ground isn't a canbus feature.

The canbus consists of two interface between major control modules. The two wire bus carries a data stream the allows every module to communicate with other module.

2. Your example of a brake light switch replacement isn't accurate. The brake light switch isn't connected to the canbus and can easily be replaced without the aid of a computer.

Thanks for the corrections. I've been carrying around in my head the explanation I was given by my BMW mechanic back in 2005 over a cup of coffee. He used the brake light switch as an example. Looking at a circuit diagram schematic of the Spyder RT the main components do appear to be stung out along a single wire, but thanks for putting that right also. :f_spider:

[GeoffCee]

Can Hi and Can Low....... I guess this isn't the same thing as the pos and neg wires in a normal circuit, otherwise there wouldn't be a need for an ECU?

For instance, in my house the power sockets are wired as a ring main, perhaps that is a better ananlogy to use when describing the wiring in a canbus system. If a component in the ring (or canbus) throws up a fault code it would have to be cleared from the ECU even though the faulty unit had been replaced by a serviceable one. Am I on the right track now, I am obviously struggling with the concept here...:helpsmilie:

[NancysToy]

Can Hi and Can Low....... I guess this isn't the same thing as the pos and neg wires in a normal circuit, otherwise there wouldn't be a need for an ECU?

For instance, in my house the power sockets are wired as a ring main, perhaps that is a better ananlogy to use when describing the wiring in a canbus system. If a component in the ring (or canbus) throws up a fault code it would have to be cleared from the ECU even though the faulty unit had been replaced by a serviceable one. Am I on the right track now, I am obviously struggling with the concept here...:helpsmilie:
This is Roger's territory, but maybe I can explain in simple terms (since I understand little else). You are confusing the CAN-bus, which is message circuits similar to the computer network wiring in your workplace, with the power wiring, which provides 12V power to various devices, similar to what the 110V wiring in your house or workplace. The two are totally different, and are not directly connected. If you look at the portion of the diagram above, you can see two Controller Area Network busses, CAN-HI and CAN-LO. Both are message networks. This would be similar to having two network cables, to handle different functions. If you look below the page title, you will see a junction labeled 8-MFB. This is the main 12V power supply from the battery. This is a completely different set of circuits. These provide power, not messages.

I hope I haven't screwed this up. Roger can correct me if I did. If I got it right, I hope it helps.

[GeoffCee]

Thanks for your input, Scotty, I guess I need to go away and read a dummy's guide to CAN-bus circuitry. This mess I find myself in started because I repeated something I remembered being told seven years ago, except that it appears I didn't remember it at all well. You need to be sure of your facts around here, that's a lesson learned which I won't forget in a hurry. :opps:

[GeoffCee]

Roger, I've spent upwards of 2 hours reading Wikipedia and Bosch explanations of what CAN-bus means, with special reference to the practicalities of vehicle electrics. I have absorbed the more easily understood stuff, (maybe 20%), but not having a background in which microcontrollers have featured, other than as a consumer, I feel this is a topic best left to experts. :dontknow: Dammit, I know when I'm licked. :joke::roflblack:

[NancysToy]

And I suppose the adage of "If you can't explain it clearly then it means you don't really understand it" may apply here.
Roger, if you can't explain it, then I don't have a snowball's chance in you know where. I liked the USB reference. I wish I had thought of that one. Anyway, I think things are clearer now. Thanks for chiming in. :thumbup:

[NancysToy]

Okay, glad someone thinks it helped.

Actually re-reading my posts here I think the waters are sufficiently muddied so that most normal people reading it will reach for their mouse and click on to next item before their eyes start to bleed.
:roflblack: Are you saying I'm not normal? :roflblack::roflblack::roflblack:

[GeoffCee]

Okay one last try on the two wire thing, then I'm done.

Sounds like an apology but I know for sure I am more informed now than I was, partly because I felt obliged to brush up in order to be able to continue to converse and certainly your explanations have helped. So thank you.

I post to SpyderLovers to help and be helped. I've actually run across people who, as you say, bash you around the ears with their specialised knowledge, condescending jerks whom you correctly describe as not having a life. Never fear, you are not one of them, Roger.


Now, a neat trick of electronic circuits is something engineers call Common Mode Rejection. What this basically means is...

There you go again, talking dirty... :hun: :roflblack: