Why Run the R/R Ground to the Battery?

[RJ]

What's the diff between running to the battery and the frame.

[chuckycheese]

None

There is no difference as long as you're getting a good, solid ground. However, it's a really popular thing to do.

[BassCliff]

Cooking with electrons

Hi Mr. RJ,

Running the r/r ground wire directly to the battery eliminates resistance that can be caused by a bad ground connection. Electrically (theoretically), there is no real difference, but in practice there can be a big difference. I chose to eliminate the possibility of a bad ground, and the extra frame resistance, and ran my r/r ground wire directly to the negative battery terminal. It makes your charging system happy.

Thank you for your indulgence,

BassCliff

[hampshirehog]

When I re-wire my bikes I only ever put one -ve lead on to the battery and create an earth as close as possible that everything else links in to. Makes popping the battery in and out easier plus it's almost the same as linking directly to the -ve.

[simon kuether]

What Basscliff said.Cheers,Simon.

[SqDancerLynn1]

A bad ground will make the regulator run hotter than it should

[doctorgonzo]

Because then your ground is in a clean. well maintained place you see all the time instead of hidden in the nether regions of the bike where you forget about it leading to it degrading because it's never cleaned and checked..

[duaneage]

Ground leads should be as short as possible. The frame is a really large piece of metal that serves as a great ground lead. All the bike's electrical parts are grounded to the frame at some point.

The RR runs the bike first, charges the battery second. If the RR and the battery have exclusive rights to the ground lead at the expense of the bike there are going to be problems. The battery has a really big ground lead going to the frame to enable it to deliver 20-25 amps when cranking the starter motor. The RR needs to deliver up to 15 amps to power the bike and keep the battery topped off. Going from RR to battery, then down the ground wire to the frame puts the RR at a different level than the bike and sets up a condition sometimes call ground bonding or jumper grounding.

Ground the RR to the frame on a short lead, check the grounds for the lights, coils, and ignition parts, and you'll be one step ahead of the game. Alternatively you could run separate ground wires for all the electrical parts back to the battery but that would be a lot of work.

Many people mistakenly think the battery runs the bike, with it's great big wires it has to be powering everything. The battery is really just a large filter that smooths out the RR output. Unhook the battery from a running bike and it should stay running. The lights may flicker at low RPMs but it will run. If it does not there are issues to be addressed.

The case on the RR is not grounded, hence the separate wire for ground. You can jumper over to the battery without harm, but make sure that RR gets to the frame where it belongs.

Don't throw anything at me , I'm only trying to be educational.

[don_gibb6512]

I asked this on another thread but never got an answer and since we're on the topic of grounds, I didn't think it would hurt this thread. Is there anything wrong with grounding the coil relay to the coil mount at the frame point? It appeared to be a good, solid ground point and will remain clean and dirt free for the most part. So far, it's working great and was the shortest distance.

Thanks.

[BassCliff]

Cooking with electrons

I asked this on another thread but never got an answer and since we're on the topic of grounds, I didn't think it would hurt this thread. Is there anything wrong with grounding the coil relay to the coil mount at the frame point? It appeared to be a good, solid ground point and will remain clean and dirt free for the most part. So far, it's working great and was the shortest distance.

Thanks.

Hi Mr. don_gibb6512,

As I understand this, with my limited electrical skills...

As long as you have a good, clean ground connection to the frame from the relay, and the negative battery terminal has a good, clean connection to the motor (or frame), then, electrically speaking, you should be fine.

It was hard to get to, but the ground wire connection to the back of the motor (from the negative battery terminal) was pretty corroded. Once I cleaned that up, my bike actually ran better and all the lights were brighter. Because this main grounding point is often corroded, that's why the direct ground connection from the r/r is recommended. A lot of GS bikes had the r/r grounded to the battery box. Sometimes the battery box could not conduct well because it was attached with rubber bushings to dampen vibrations, I suppose. Thus leaving the grounding path only through the bolts, which often corrode.

Thank you for your indulgence,

BassCliff