How to start
What can you control about your car?
The four things that you can really control
Losses due to electrical electrical resistance
Losses due to poor gearing
Possible Order of Decisions
Find your motor. For example:
an ETEK motor runs at 48 volts. Plan for sufficient batteries to operate motor at the optimum efficiency A 48v motor will require require four 12volts.
Batteries,two 24 volt batteries, etc. [The number of batteries will coop with your frame]
Plan your solar array so that, it can efficiently charge your batteries batteries. A 48v motor will require at least 52 volts coming in from your solar array and producing approximately 15 amps.
How many amps do you need to meet your power settings?