"Of course the leccy bikes then needed to re-charge, after just one lap, while the 50cc bike could carry on"
The Austrian bike that Paul Dobbs rode happily made it around the circuit and was found to have enough charge remaining to have completed another full lap. A 50cc bike would also need refuelling after 2 laps at race speed. The 125 we used to race there (Before they removed the ultra lightweight class) would be almost literally running on fumes after 2 laps.
Now the team has some race data, they are looking at various options for improving on the 62.6mph average(*) speed, which could include using lighter batteries since they found the bike was carrying almost double the charge it needed to finish, or a more powerful motor to take advantage of the extra charge. Its a delicate balancing act between power, weight and air resistance.
(*) Paul was pulling significantly higher top speeds.
By the way, 50cc race bikes are pretty fucking far from a 'putt putt' and I'd like to see you even match the lap record around the TT circuit on a 'proper' road bike.
The comparison of energy density between petrol and batteries and the efficiency of the respective engines is really interesting - batteries have something like 1/10th of the yield of petrol, but the internal combustion engine wastes something mad like 75% of that energy in heat and friction while the electric motor is much more efficient, losing something like 7-15%. (Numbers quoted from an article in this weeks MCN)
@NOT Zero Emmission
The race is billed as zero CARBON, not emission. Take a look at http://www.ttxgp.com, which says -
"TTXGP - World's First Zero Carbon, Clean Emission Grand Prix"