Hi Knoxie. Thanks!
I geared it with the intention of going with 48 volts when I get a new battery. With the present 36 volt set-up, I'm getting a top speed of about 19mph (off-road:) so, with a more optimal 48 Volt set-up, about 26mph - which is all I need.
You can draw peaks of over 35 amps from the 4 Ah of Ni Cads but you certainly pay for it (energy wise).
Averaging 12 Wh per mile in a hilly area - should be able to improve on this, once everything is optimised.
The backpack, with batteries in, weighs 6.5 kg - I really don't notice the weight at all when I'm riding.
The good thing about Randy's motor is the form factor - the case is only 60mm deep. You might need a longer BB axle to fit a Koll or BMC in, perhaps?
Adding some power to the Strida sounds like a fun project
Yes, it's a one-way bearing but bonded into the adapter that I made. My first pulley build used the Strida 3 pulley which has a fixing for an 18t sprocket as its center - so it was easiest just to use an 18t freewheel, for that - but I got fed up with the clicking sound...