If you use a normal 250w geared motor at 48v, you get all the hill-climbing power you need. It will be light and pleasant to ride both with and without power. You get an on the road speed of about 24 mph flat-out, which is very well suited to bicycles. Best of all, it's legal.
That sounds like what i need to look at for this one as i want the person that this is built for to have a good experience, on the flat it will do fine and pull at 20+ mph but as soon as it hits a hill it just slows down to a crawl.
I have no doubt that there will have to be pedal power to get up the hill but i was so surprised at how much pedaling was needed.
With the controller connected to my 1500W bike today on the way to work, the hill that i climb up at 20+ everyday, it managed to push enough power to get up at 12 mph so its defo the motor that just cant do the hill.
I will do some further testing and see if i can tweak the power to give the best possible power output without killing either motor or controller