yep have them on both bikes six volt system on the flash with Lucas voltage regulator and the Rocket has belt and V-reg, now I know the DVR2 gets rave reviews and rightly so, I suspected my V-reg was not in the same league as the battery was never at full charge , turns out the V reg is fine it was he battery that was duff, would only hold a charge of 10 to 11 volts, I've got two Burlen types wired in series and get full twelve = magic