Need help choosing an appropriate kit for long ride

[Trevormonty]

A factory mid drive eg Bosch/shimano steps with IGH would be lowest maintenance option, but not cheap >£2-2.5k.

 

[KirstinS]

I would use a 500w Bafang BPM motor at 48v and ariund 20 amps. Those motors are real workhorses and more ssuited to stop-start riding than a direct drive motor.

A normal battery would last about a year, but if you get Jimmy to make you up a 15 or 20 Ah one with his Boston cells, it should last four times as long. You could put the battery and controller in a bag like this:

So I can give you some real world equivalent experience. I have a 15 mile round trip commute that is pretty flat (mostly seafront ). No charging at work.

For some time I ran a 36v 350w front BPM with a 48v controller at 52v

It went very fast, too fast really in my book at 30mph hot off charger and settling to 26/27mph. At 44.4v it was perfect

It used between 5 and 10ah depending on conditions (head winds round here can be really fierce)

 

[Woosh]

the BPM is a very versatile motor. Using the same motor with 36V battery, it'll get you to 23-24mph and 28-30 mph with 48V battery, Beyond 30mph, it has to be DD motors but then, you'll need 1.5KW or more. I really can't see the point of having 500W or 1000W DD motors other than they cost a bit less to buy.

 

[danielrlee]

Beyond 30mph, it has to be DD motors but then, you'll need 1.5KW or more. I really can't see the point of having 500W or 1000W DD motors other than they cost a bit less to buy.

This just demonstrates the often arbitrary 'ratings' that motors (and controllers for that matter) are given. Around 1300W is required to maintain 30mph and I've never found a 1000W DD motor that couldn't maintain 30mph indefinitely without overheating. I've never experienced a 500W DD motor, but I'd be surprised if one also couldn't sustain 30mph.

Of course, if you run any motor of any size inefficiently enough, you'll be able to overheat it, so there are eventual limits.