i know you can take abunch of double a rechargeable batterys and wire them up together to make abigger battery, say i made one that fit in that little squar place under the seat, and took the tail light as the charger. would that work?
it's not that simple.
our AC output must be rectified to DC to charge a DC battery.
the ground of the lighting system must be disconnected from the stator plate and ran to the ac to dc rectifier,
for it to work properly it needs both a + and - input,
the + and - output of the rectifier is what charges the battery.
the battery and wiring used must have sufficient capacity (amperage) to run whatever it is your adding a rectifier/battery system for ?