I'm a newcomer to this so forgive me if my thinking's still a bit out of the box.
After spending several days in cruising the web I only have the roughest idea of what is happening. What I am aiming for is long range rather than speed or style. 20 or even 15 mph would be more than enough for me if long range can be achieved. In real terms, e-bikes or pedelecs are really commuter bikes in terms of range.
For the sake of raising the bar let's just say that the target on road touring range is to be 400 miles over a theoretical level (flat/horizontal) road without hills. The question is: how is that range to be achieved? I know it sounds mad but let's go for it. because if we don't try we'll never do it.
As everyone knows, the main limiting factors are weight or mass, wind resistance, human and battery power, i.e. bigger battery = greater mass = greater energy requirement.
Real world constraints:
There are numerous obvious trade-offs but several lateral thoughts emerge that others may have researched properly, in engineering fashion. For extended range how about:
I'm delighted to have stumbled over this forum and I look forward to learning a lot from those who beat me to it.
After spending several days in cruising the web I only have the roughest idea of what is happening. What I am aiming for is long range rather than speed or style. 20 or even 15 mph would be more than enough for me if long range can be achieved. In real terms, e-bikes or pedelecs are really commuter bikes in terms of range.
For the sake of raising the bar let's just say that the target on road touring range is to be 400 miles over a theoretical level (flat/horizontal) road without hills. The question is: how is that range to be achieved? I know it sounds mad but let's go for it. because if we don't try we'll never do it.
As everyone knows, the main limiting factors are weight or mass, wind resistance, human and battery power, i.e. bigger battery = greater mass = greater energy requirement.
Real world constraints:
- LEGALITIES: Wattage of motor, weight of bike, maximum speed, is a trailer legally permissible on an ebike or pedelec? I'd like to ignore these, probably like many others, but I value my licences too much.
- GROSS WEIGHT of COMPLETE SETUP
- Ah, VOLTAGE and WEIGHT of BATTERIES
- POWER of MOTOR (let's stick with the UK legal max. of 250 watts for this exercise)
- UPGRADED BRAKES: because of the additional towed weight of trailer and batteries the brakes would probably need to be upgraded so adding more weight (minimal).
- FITNESS, STRENGTH & STAMINA of RIDER: Assume rider to be a fit 30 year old but one who does little or no strenuous or regular exercise.
- SPEED -v- WIND RESISTANCE: higher speed = less miles per watt. Use 12 mph as the average speed throughout.
- TOTAL COST: Other than style and go faster' paint jobs it seems to me that there's little performance difference between some bikes that could cost much less than £500 and those at £2,500 or much more. I've seen advertisements from one German company who offer pedelecs with a range of 200+ kilometers but I have grave misgivings about phrases in adverts like "up to" and "depending on". It's time that there was one method of unequivocally specifying performance for all ebikes and pedelecs...but that's a different subject worthy of its own thread.
There are numerous obvious trade-offs but several lateral thoughts emerge that others may have researched properly, in engineering fashion. For extended range how about:
- towing batteries on a trailer behind the bike. Apart from inertia in starting from 0 mph and in accelerating, most of the trailer and battery weight is a vertical downwards component, supported by the trailer wheels. Allowing for some frictional and aerodynamic losses it seems to me that in the trailer idea there's a lot of potential to substantially increase range.
- perhaps even with two 'standard'(?) batteries a very small small generator and charger could be carried on the trailer and run to charge one battery or more while another battery is being used to hel power the pedelec. It's a thought at least.
I'm delighted to have stumbled over this forum and I look forward to learning a lot from those who beat me to it.