I know I need a new Reg/Rec for my 96 175 Fast Strike as the tach circuit doesn't work in the one I have. Looking over my options I came across CDI's reg/rec but the installation instructions say in bold lettering not to use an AGM, Maintenance Free, or Gel Cell batteries with this type of reg/rec.

Anyone know why this is? I use an optima as my start battery and haven't seen any ill effects this last year on the stock reg/rec (the tach circuit was bad before last season)