I have 6v, also with halogen lights (35/35, 21/5), but apart from a battery to engine case earth for the generator, I have no battery to frame-earth connection but run good (10A) earth wire to all services. Tail/brake light is nice and bright, but in ambient (streetlight) areas, I have to check with 'hand-over' if the headlight is on.....
The new aftermarket horn also scares the crap outta me. ...when I accidentally knock it
When I collect my young fella from the airport, I wait out the back where there's a bushland reserve, and last time I coulda sworn I saw one (D.B) run out of the bushes and across the tarmac ...if it got into the landing gear it could end up anywhere
They're tenacious critters...do anything for a drop..!!