Bonneville America Forums Forums Technical Forums General Tech Regulator to battery mod

Thanks to all for the posts and links on the charging system mods in the other thread. I want to improve the ability for the BA to charge/recharge the battery because I make a lot of very short (3-5 mile) trips and ride in cold weather which leaves me with less than ideal cranking power. I'm looking for some knowledge, wisdom and answers from the site brain tank. First, I'm curious if raising the charging voltage will cause premature low electrolite levels (from boiling the water and or converting to H & O) due to overcharging from the 14-14.5 volts some have reported after the mod versus the 13.2v I have now at fast idle. Secondly, I am wondering if the regulator does it's job, won't it eventually return the charging voltage to the design specs? And last but not least, if we increase the positive wire size from the regulator to the battery and shorten its length, will we need to use the same wire size and make the ground from the battery to the engine shorter also? Thanks, Steve

the alternator won't reach max charging voltage until the engine is running at about 2000 RPM on nearly every motorcycle made these days. You will probably see 14 volts there.
Unfortunately, Regulators are now voltage control only. It is pushing too much current into a battery that does the most damage and that isn't regulated directly anymore.
The ground wire is designed to carry the current used by the starter so it should be OK as is.

I did the mod to increase the wire size and shorten its length from the regulator to the battery. After much knuckle scraping trying to get the regulator unplugged and the wires near the connector accessable, I found the black/red wire from the regulator. Using the handy dandy wire strippers (and an old sharp pocket knife) removed a 1/2 inch piece of insulation, made a buttonhook (an eye through the middle of the wire). Then I stripped an inch of insulation from the 12 gauge lead of a 30 amp inline fuse holder, divided the wire in half and wound it through and around the copper wire of the eye. Then soldered (just do it) the connection for good measure, wrapped with tape, covered with flexable split wire cover. put a ring terminal on the battery end of the new wire and connected the battery. The before and after numbers were:

Standing volts (off) 12.60 12.59 -.01

Fast idle (2000 or so) 13.20 13.70 +.50 good!

Slow idle (putt-putt) 14.20 14.50 +.30 good!

All in all, it was a cheap fix and I am getting more volts back to the battery. None of the OEM wiring was changed, just another shorter fused wire was added for a closer and additional path for charging and or using electric power. Oh, these readings were with the headlight on high, no other accessories on.