wiring a regulator/rectifier on auxillary outboard

[bumperfood]

I have a 16ft fiberglass bay boat, with a two stroke 50hp Yamaha tiller. It has electric start and a 6amp charging system. The charging rate is just adequate for my needs, but the engine is not conductive to prolonged *****ing. To address this I am installing a two stroke, manual start, 8hp Yamaha as an auxiliary for *****ing purposes. It has a charging circuit(6amp according to the manual) as is evident by the two green wires coming from under the flywheel. I have installed the correct regulator/rectifier. My question relates to the wiring for the battery. I have only one battery, and no room for another.

Do I have to run the charging wires red to pos, black to neg, directly to the battery terminals, or can I just run the two wires to the main engine battery cables under the 50hp cowling?

I understand that I cannot run the 8hp with the battery disconnected, as damage to the regulator will result. But, could I safely run either or both engines if the charging circuits are hooked up either way as previously stated? Any other suggestions or ideas would be appreciated as well.

[boats.net]

Best to run charge wires direct to battery and install a inline fuse on positive wire. You would be able to run both engines if need to.

[bumperfood]

Thank you, that is what I will do. One other question. It seems that the regulator/rectifier body acts as its own ground through the case. All the other componenents that require grounding (with no battery connected) are grounded to the engine block. Would it be overthinking to run the ground wire from the regulator to the engine block and then to the negative terminal of the battery, as well as having the regulator body grounded?

[boats.net]

It should ground itself but extra ground wire wouldn't hurt.

[bumperfood]

Thank you for your quick and helpful responses.