Originally Posted by DEcosse
The same current flows through both supply & return - if you upgrade one side, you should also upgrade the return.
Your kit, your customer's choice I guess
Yes, the current flows through both legs. However, some things to consider:
- The (+) leg from battery to solenoid and solenoid to starter is 42" in length. The wire starts at 6 AWG and necks down to 8 AWG at the solenoid.
- The ground length is 27" and is 6 AWG. This is about 35% shorter than the (+) leg and is thicker throughout.
The voltage drop in the (+) leg is greater than the (-) leg. Equalizing (approximately) the legs is where the real benefit lies.
We've tried 4AWG throughout, 6AWG thoughout, and combinations therein. In the end, we selected what we did based on actual starting performance, ease of installation, and attempted to minimize clutter under the seat. In the beginning, two additional 4AWG cables really added some bulk around the battery. If you add a battery tender lead, heated gear, and/or fuse panels, the real estate gets cramped very quickly.
The real proof, however, is in the cranking speed. I've down numerous trials here on an 05, 07, and 08. Results are consistent from bike to bike.
With the ground cable:
Without the ground cable:
On a side note, a weak spot on the 1050's I've had here has been with cable corrosion - primarily on the solenoid to starter cable. The lugs are not soldered and there is no heat shrink. Corrosion begins at the lug and starts to work it's way up the cable. This isn't enough to cause problems in most cases, but over time as the bike ages...you get the idea.