Do I need to ground my electrics?

Unclviny said:

My plan is to run a big-ground wire from the battery and tie all the ground wires to it neatly, does this make sense? and should I terminate the end of the big-wire or should I bolt it to the coil bracketry??

Vince

Click to expand...

The ideal analog circuit brings a separate ground wire back to the battery (or power supply) for each circuit, like the spokes of a wheel radiating towards the hub. Your scheme is as far from ideal as one can get, but would work for motorcycle wiring with the possible exception of electronic and LED circuits. In an electronic circuit, where millivolt differences can cause huge problems, one common ground bus causes "ground loops" and should always be avoided. By "terminating the end of the big wire", do you mean to tie it to frame? In your scheme, there would be no point to do so, unless you also strapped the battery earth terminal to the frame ....then this would be using the frame as ground and sort of nullifies the single bus wire ground you contemplate.

I would stay with the more conventional forms of ground wiring.

Slick

I think the conventional route is to establish a solid point from the battery to the frame, then supplement as needed where the flow is questionable. The isolastic is a good example if this along with the steering head bearings. This is why some run a short coiled wire from the coil mount area to the head and perhap a dedicated wire to the headlamp shell.
No need to over do it as long as the connections are solid and clean.

So should I not use a "grounding block" with a common wire going to the battery? or should I just run the grounds for electronics and LED's direct to the battery and use a "grounding block" for everything else?

By "terminate" I meant seal the end of the wire so it is not making contact with anything, it was going to just be a "common path" to the battery.

Vince

Unclviny said:

So should I not use a "grounding block" with a common wire going to the battery? or should I just run the grounds for electronics and LED's direct to the battery and use a "grounding block" for everything else?

By "terminate" I meant seal the end of the wire so it is not making contact with anything, it was going to just be a "common path" to the battery.

Vince

Click to expand...

You can use a grounding block (also called a "buss bar") to act as a common point for all power-consuming devices. Bring the return wires back from everything to this bar, including (especially) the ground post of the battery and voltage regulator/rectifier. Make sure you also have a sizable wire coming from the buss to the engine (typically seen at the head).
If you've an electric start, the only ground wire from the engine block should be as large as the hot wire to the starter solenoid, and it must connect directly to the ground post on the battery. Believe it or not, as long as each item has its own ground/return wire, a frame ground isn't necessary, although it's a good idea to help bleed off any extraneous static charges.
I know the thought of not using the frame as the "ground" seems to contradict the conventional way of thinking, but the frame isn't the best way of creating a return path for the power devices. If you dig into house wiring and/or power boxes that supply large electronic equipment, you'll find buss bars for both the hot and return loops that give common points for everything to tie to. It's usually at this point that they tie the frame to ground, and nowhere else.
Nathan

I have no issues with Nater's advice and suggestions except to advise that a ground block can be distinct from a ground bus. In my jargon, a ground bus can be of considerable length, traveling around the periphery of a circuit (like around the four sides of a circuit board). Unclivey's single ground wire is that sort of ground bus. The length of bus between tie in points can cause ground loops that can be trouble with digital and electronic circuits, although typical motorcycle electrics will not be affected . However, electronics, like digital clocks and electronic ignitions, can be sensitive to ground loops.

A ground block is a compact, multi-terminal, connection point that functions like the hub in my wheel spoke analogy above. I think Nater's ground bus is a short, heavy gauge, conductor used as a multi-terminal junction. The key point is "short".

One final point, it is not absolutely necessary to have each circuit have its own ground wire back to the ground block. For practicality, some sharing of ground wires can occur...for example, R & L turn signal lamps can be on one wire. High amp circuits should, as Nater suggests, be of same gauge as the supply, and run independently back to the battery (starter ground) or the ground block.

Slick

I'd been trying to decide whether to return the wiring on my recently acquired 850 MK2A back to standard or leave the myriad of additional ground wires as they are and I'm still not 100% convinced. The bike had a new wiring harness fitted by the previous owner and he's put in so many extra wires wires that it resembles a ball of wool a cat has been playing with :?

This is only one of a list of things I need to clear up but I'm trying to use the search engine to answer my questions rather than pestering everyone when the answers are there to be found. It's been a long time since I messed about with an old British bike though I do have a similar aged Kawasaki 750H2 which is a cause of constant headaches.

Re: Andy_B post

Andy wrote: "and he's put in so many extra wires wires that it resembles a ball of wool a cat has been playing with "

This is the sort of thing that will drive you crazy troubleshooting a future problem. I would consider going back to a factory stock harness....then you will have, or can get, a wiring diagram to help you sort things out.

Saber13 on this Forum, has posted that he has wiring diagrams in digital format, and has offered them to anyone on the Forum....just PM him.

Slick

Grounds are over-rated. What's important is to put the smoke back in the wires, that is money well spent.

texasSlick said:

...electronics, like digital clocks and electronic ignitions, can be sensitive to ground loops.

A ground block is a compact, multi-terminal, connection point that functions like the hub in my wheel spoke analogy above. I think Nater's ground bus is a short, heavy gauge, conductor used as a multi-terminal junction. The key point is "short".

Click to expand...

Absolutely. Ground busses in power supplies and/or panels are typically heavy copper strips with a number of threaded holes where wiring lugs can be attached, thus giving everything a common point of return. A home-brew is usually a store-bought terminal strip, which can be interconnected with jumpers http://www.mcmaster.com/#terminal-blocks/=sjbz0c They're used extensively on fiberglass boats and automobiles where there's no convenient ground. They can also be found in red to denote the "+" side (great for our positive earth vehicles). Search "terminal strip block with jumper" for a plethora of images denoting such.

texasSlick said:

One final point, it is not absolutely necessary to have each circuit have its own ground wire back to the ground block. For practicality, some sharing of ground wires can occur...for example, R & L turn signal lamps can be on one wire. High amp circuits should, as Nater suggests, be of same gauge as the supply, and run independently back to the battery (starter ground) or the ground block.
Slick

Click to expand...

Agree whole-heartedly. My issue is when ancillary items get randomly "grounded" to headlight buckets, taillight housings, exhaust pipes, air filters, and any of a number of very creative points, then wondering why there's all kinds of electrical gremlins running around. As long as items such as the headlight bucket and taillight housing are properly grounded themselves, you're fine, but those items will usually have a dedicated ground wire back to the ground buss or battery. Slick, thanks for the clarification!

Nathan

Nortiboy said:

gripper said:

Earths back to the battery is the way ahead, if you rely on the frame, OK until you come to the bits on the forks, then the conductivity of the headstock bearings (or lack of it) will leave you with shite lights and handlebar switching. "Fail" as my kids say.

Click to expand...

There are earth wires connected to the headlight shell that look after this issue.

Cheers

Click to expand...

Sorry I don't agree. The headlamp bulbs need an earth that connects to the battery directly through a heavy wire or the voltage drop will kill your lights, likewise not running relays on both beams , you may as well light a candle. See comments on wiring. and the 20b relay etcetc

Nortiboy said:

gripper said:

Earths back to the battery is the way ahead, if you rely on the frame, OK until you come to the bits on the forks, then the conductivity of the headstock bearings (or lack of it) will leave you with shite lights and handlebar switching. "Fail" as my kids say.

Click to expand...

There are earth wires connected to the headlight shell that look after this issue.

Cheers

Click to expand...

Sorry I don't agree. The headlamp bulbs need an earth that connects to the battery directly through a heavy wire or the voltage drop will kill your lights, likewise not running relays on both beams , you may as well light a candle. See comments on wiring. and the 20b relay etcetc