OK, so it's one of those 500W direct drive motor kits. That explains the lack of climbing ability. What you need is a 500w geared motor, ideally running at 48v, but the complete kit would cost around £600 to £700. I'm guessing that you have a 22 amp controller and a battery capable of 25 amps.
I think you have two options. Option 1 is a 36V Xiongda 2- speed motor kit, which will cost about £250. The kit includes the motor, controller, PAS, throttle an LCD. You have to buy your own rim and spokes and lace the wheel yourself. That can be done yourself for £30. If you can find a bike shop to do it for you, they charge about £30 to £50 labour. If they provide the rim and spokes, probably £100. The Xiongda motor isn't particularly powerful, but when you come to a hill, it automatically changes down to a lower gear and winches you up at about 6 mph. The controller is only 15 amps, but a blob of solder on the shunt will increase it to around 18 amps to give more all-round performance.
Option 2 is a 500W Bafang BPM motor. It's a brute force approach. One of these motors at 36v and 30 amps or 48v and 20 amps will drag you up any hill. If you get one of these, you could try it with your existing controller and battery. Again, a small blob of solder on the shunt in your controller will increase the current to around 25 amps. That will give you a lot more climbing power than you have now. If you find that you still need more, you can replace your battery and controller with 48v ones at a later date, which will give you more power and a better control system. The motor will cost around £250 to £300 ready laced.
bmsbattery.com
Make sure you tick 201 rpm. They have a nasty habit of sensing out sensor less versions, so ask them by email if it has hall sensors, then write in the special notes for your order that it must be with hall sensors.
Out of the two options, I prefer option 2 because you get a simple bolt-in solution that will probably give you what you need. Top speed will be around 15 mph. If you go up to 48v later, the speed will go up to 22 mph and you get 33% more climbing power, but that will cost around £400 extra. The motors don't care about voltage. The 48v 260 rpm version is identical to the 36v 201 rpm in all respects except the marking.
The advantage of option 1 is that it's completely legal.
I think you have two options. Option 1 is a 36V Xiongda 2- speed motor kit, which will cost about £250. The kit includes the motor, controller, PAS, throttle an LCD. You have to buy your own rim and spokes and lace the wheel yourself. That can be done yourself for £30. If you can find a bike shop to do it for you, they charge about £30 to £50 labour. If they provide the rim and spokes, probably £100. The Xiongda motor isn't particularly powerful, but when you come to a hill, it automatically changes down to a lower gear and winches you up at about 6 mph. The controller is only 15 amps, but a blob of solder on the shunt will increase it to around 18 amps to give more all-round performance.
Option 2 is a 500W Bafang BPM motor. It's a brute force approach. One of these motors at 36v and 30 amps or 48v and 20 amps will drag you up any hill. If you get one of these, you could try it with your existing controller and battery. Again, a small blob of solder on the shunt in your controller will increase the current to around 25 amps. That will give you a lot more climbing power than you have now. If you find that you still need more, you can replace your battery and controller with 48v ones at a later date, which will give you more power and a better control system. The motor will cost around £250 to £300 ready laced.
Bafang BPM2 36V500W Rear Driving E-Bike Motor Wheel RPM 201
Bafang BPM 36V500W Rear Driving Hub Motor E-Bike Wheel. You can select S09P, S12P or S12S controller for this motor.
bmsbattery.com
Make sure you tick 201 rpm. They have a nasty habit of sensing out sensor less versions, so ask them by email if it has hall sensors, then write in the special notes for your order that it must be with hall sensors.
Out of the two options, I prefer option 2 because you get a simple bolt-in solution that will probably give you what you need. Top speed will be around 15 mph. If you go up to 48v later, the speed will go up to 22 mph and you get 33% more climbing power, but that will cost around £400 extra. The motors don't care about voltage. The 48v 260 rpm version is identical to the 36v 201 rpm in all respects except the marking.
The advantage of option 1 is that it's completely legal.
