I am with Ben,
I assumed that the OP was talking about a part 103 aircraft and that he would naturally account for the weight and balance implications and the overall design loads of the aircraft.
A part 103 has a very restricted minimum weight hence the inquiry.
I disagree that fuel and battery should be different neither of them if removed would allow flight- remove the battery- no electric engine will work . Same for a fueled engine- remove the petrol it will not work. So are they are the energy source for the engine they should be treated the same. The idea that the petrol is consumed and the electric battery is not is incorrect- the energy available is most definitely consumed and a tiny amount of mass is lost. If it were the case that a part 103 could not safely land with its tank of petrol still full- then this argument may hold- but that is obviously not true.
Any aircraft will have a MTOW and this also includes a part 103. I did not imply that should ever be exceeded at any point, nor that any normal rules of airmanship or design loads should be exceeded.
The design for placement of the battery powersource is in fact more simple as it does not significantly change during flight. This is unlike petrol which gets its mass consumed during flight and thus effecting weight and balance.
IF we are ever going to see the intergration of electric flight systems into our sport, then these are the issues we need to consider. Just like the change from metal structures to composites, it is most successful when we stop thinking in the metal box but with the ability of composite in mind. The same applies for electric.