My bike is this one:
http://www.huffy.com/Products/Product.aspx?pid=383|4|8
I converted it to a ebike late last year. Then about a month ago, I converted it to a mid-drive system by getting a new mounting bracket for the motor. After I did that it's been pushing along with little down time. The original side mounted method was unreliable since the bracket eventually began flexing under the torque causing the chain to derail.
Now that it's a mid drive system, the chain is further away from the wheel and is going through the derailer. Now I'm able to change gears and keep proper tension on the chain. Once I get the bottom bracket spacers, I will align the bracket even better and then install the motor freewheel cog and run it through the pedal chainwheel (which is now on a freewheel as well). That way I can pedal the bike when I want to. But for now it's all electric and can't be pedaled yet.
It will do about 25MPH on level ground with no resistance after hitting sixth gear. However it will average about 21-22MPH if there is a slight incline or wind resistance.
My town is reletively flat. The "hilliest" areas in my area would be the intersection with the rail rode tracks which appear to be roughly a 10-15 degree incline. My bike has no trouble going over it. With my setup, I'm pretty sure I can handle most hills that I could theoretically run into. For a place like San Fransico which has very steep inclines. I suspect it could still work there too provided that I get a new rear freewheel with a bigger first gear. Since it's mid-drive, I can use the same gearing that the pedals originally used, so I can just use bigger gears on the back to get more torque.
My system is a 36v 350 watt with a brushed motor. The battery is a 36v 12ah LifePo4 (Lithium battery and weighs in at 13 pounds almost) I ran it through 3 or so cycles thus far and it is holding up great. The last cycle I ran it all the way till it cut off since I needed to figure out the range. So even after doing that, it charged up to full charge is under 2 hours and still works great. So looks like the battery has no defects what so ever. Compare that to my old 30+ pound SLA batteries. They went less then half the distance my new battery takes me (and they were 12ah capacity too!) and were heavy as ****.
The motor does have a gear box by the way so there is usually enough inertia in the motor so that when I throttle down it will take a bit of time before it stops spinning. So because of that, I can still change gears if I let go of the throttle.
