I wanted an accessory system which doesn't rely on the bike's own system as I have no idea about the route that my components will then take to ground and the capacity of the connectors and cables to take my additional load. The cable to the battery looks thick enough, but I'm not one to make assumptions.
In the scenario I have laid out for the purpose of this discussion no additional capacity is being added to any of the existing ground connectors or ground wires that are already there. The accessory would be grounded directly the the engine/frame (preferably engine) through its own ground connection. The ground path would be through the mass of the engine back to the negative battery cable.
I wanted my accessories to be easily isolated from the bike's electrics so that if I ever have an electrical issue, I can eliminate my add-ons as the cause by disconnecting one connector.
This is the one advantage that I see to date about having a ground bar- the convenience factor of one connection if troubleshooting becomes necessary. In my scenario I am ignoring the convenience factor for the purpose of this discussion. This is because I am trying to learn/determine if there is a technical or theoretical advantage. i.e. Does having this additional ground bar make the electrical circuit deliver the current in a superior manner, barring any defects, than does using the engine/frame?
However, the question I would ask you is could isolating your added accessories not be accomplished by simply disconnecting the +ve to your accessory fuse block? I don't understand the need for a seperate ground bar to accomplish this.
I didn't want a number of connections stacked up at any single point. So I have one +ve connection and one -ve connection - both to the battery. Everything else comes from my own connectors built into my own wiring harness which is properly fused and relayed as appropriate
Agreed but again the convenience factor that I am not disputing.
If my accessory wiring fails I don't want it to affect the bikes normal electrics.
As I am suggesting that all accessories be grounded through their own separate ground wires and connectors apart from the bikes existing ground wires and connectors, a failure in the ground path of any accessory should only affect that accessory.
But it looks as though I have made an assumption after all. As @spiderman302 pointed out, when the bike is running, the power is coming from the alternator, not from the battery. So in connecting to that battery post, it looks as though I may be adding to the current being put along the main battery leads to the alternator and to ground.
The technical training that I received as a GM technician was that a ground connection is always to be made to a solid attaching point on the engine first and foremost whenever possible because of this reason. Grounding to the frame was always to be considered as a second choice. If a student asked about grounding directly to the battery a definite no response is what the instructor would give to that question but I can't remember if there was a specific reason. Because I was already aware of what Spiderman pointed out this is one of the primary reasons why I initially asked this question. Adding an additional ground bar makes sense to me. But I didn't know the logic behind grounding it separately from the vehicle electrical system and directly to the battery. I thought that maybe there is something different about motorcycle electrical systems that I am not aware of.
The very thing that I was trying to avoid. I'll be trying to check that out now, but fairly content in the knowledge that the power would then be coming through the main 60 Amp fuse, and that has never blown.
You previously questioned my assumption that there is more than sufficient unused capacity available in the negative battery cable. This is another reason why I am confident that the negative battery cable can easily handle the added capacity- because this fuse does not blow. The negative battery cable can carry the same load as the positive cable does. If the positive side of the circuit can handle the additional load that is being added without blowing a fuse that is rated at less than what the cable can carry, why wouldn't the negative cable also be able to handle it.
Good discussion- still has me thinking.