Battery terminals arc when connecting

[Kiwi_Roy]

I have the Elecrtosport ESR-515

This seems to be a direct replacement for the Ducati Energia, it doesn't show a ground wire so be sure to provide a good connection to the chassis.

[sculler2x]

I sure did.  8 gage wire to starter motor bolt.  4 gage wire from starter motor bolt to battery.

[Kiwi_Roy]

I sure did. 8 gage wire to starter motor bolt. 4 gage wire from starter motor bolt to battery.

 

Your #8 will do the trick for sure, it's all about voltage drop, a 6" 14 gauge to a timing cover bolt works also because the engine is a very good conductor, better than any wire and the main ground is plenty fat enough.

The factory installed a tiny wire all the way to the battery, I'm guessing 20 gauge which is next to useless because of it's length.

When installed the case to horn bracket provided a good path, but aluminium to steel in a wet environment is inviting corrosion so it falls back to the factory wire resulting in a low battery.

The regulator is set to put out 13.8 Volts between the black wire and it's case, whatever you loose between the case and the negative terminal is lost. The flakey reference to the black wire is another story.

It would be interesting to see a schematic of the Electrosport regulator, I asked for one but they are not about to share it with me.