I'm about 200 pounds, and I commute 20 miles to work each way. There are some hills, but they're not too bad. I can take the hills under my own power, it's just slow. I want to speed up my commute and make the uphill sections faster and easier.
I am considering adding a Roadrunner 4820 to my bike, powered by a Yesu LiFePo4 48V 10Ah battery. From what I read, this battery should take me 10-15 miles without any pedaling at all, and I like pedaling. I am fine pedaling the whole way, I just want to speed things up.
From what I read, this setup should get close to 25MPH... I don't think the gearing on my current bike will let me pedal at that speed. So I'm concerned that if I can't pedal assist for most of the distance, the battery will not last for the full commute. Has anyone tried getting a bigger chain ring so they can pedal assist at higher speeds? Would it make sense to do that?
My other concern is that the motor might add some resistance when the battery runs out, or if I choose to turn the throttle off for long flat sections. Will putting this motor on my bike make it a lot harder to ride when the battery is out of juice? (not counting the extra 25 pounds or so)
Should I consider the 20Ah battery? That seems like it might be overkill for me, and they're not cheap!