An 8 volt battery is a solution to a nonexistent problem. Get the 6 volt system cleaned up and working right, and donate that 8 volt battery to somebody's recycling bin. It's necessary to adjust the charging voltage to 9.5 volts to keep an 8 volt battery charged, plus adjusting the cutout relay to 8.5 volts to keep the regulator from connecting the generator to the battery too soon. Anybody with enough understanding of a DC charging system to make an 8 volt system work knows better than to try it in the first place.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!