AussieJester
1 TW
Hobby City sell two different cameras very very similar if you don't like dealing
through flebay
KiM
through flebay
KiM
Nah, will get a different motor instead. Its on the way.Mark_A_W said:You'll have to program some speed switches.
full-throttle said:Ride to work - take 2.
Comparing with my current setup
Average speed 30km/hr vs 30 km/hr - no change
Total time 45min vs 45 min - no change
Total Ah used 9Ah vs 5.5Ah - new setup used 63% more energy
Top speed 53km/hr vs 42km/hr - thumbs up for MAC
adrian_sm said:Damn that is a lot more Ah's. I would have expected a much higher average speed, not just top.
What is up with that? Just burning it up on acceleration, or more power required to cruise?
- Adrian
full-throttle said:Power goes with cube of velocity, but in this case is more to do with delta/star.
This is because F ~ k1*v^2, and P = F*v = k1*v^3. But, work/energy is.. W = F*d = k1*v^2*d. k1 and k2 are just some constant that represent the other constants in the equation that I didn't feel like writing, F is force and P is power.
Correct me if I'm wrong, but a motor wired in delta would draw more current than the same motor wired in star. I'd say twice as much. At the same time delta-wired-motor will spin faster then star-wired-motor at a given voltage. I'm not sure what the ratio is, but 1.73:1 springs to mind.swbluto said:So are you saying that delta/star has some distinctly different efficiency profile in your application(One is less efficient than the other), or that the motor wind type affects the average top speed which itself influences the energy consumption?
full-throttle said:Correct me if I'm wrong, but a motor wired in delta would draw more current than the same motor wired in star. I'd say twice as much. At the same time delta-wired-motor will spin faster then star-wired-motor at a given voltage. I'm not sure what the ratio is, but 1.73:1 springs to mind.swbluto said:So are you saying that delta/star has some distinctly different efficiency profile in your application(One is less efficient than the other), or that the motor wind type affects the average top speed which itself influences the energy consumption?
That explains why the current is higher at no load.swbluto said:..the resistance changes by the square of that so that's approximately 3 times less resistance..
So you're saying: by speed-limiting it to 42km/hr (same as the other bike) will get me similar economy?swbluto said:I'd think the air resistance would be the dominating factor
full-throttle said:So you're saying: by speed-limiting it to 42km/hr (same as the other bike) will get me similar economy?
It's definately a big factor - on my star delta hub I can pull 60-80 amps going flat chat in delta and about 30-35 amps rolling along the flat at top speed (about 70-75 km/hr @72v) but if I back off to 30 km/hr it'll draw as little as 5 amps rolling along the flat.full-throttle said:So you're saying: by speed-limiting it to 42km/hr (same as the other bike) will get me similar economy?