Now getting indifferent whether hub or crank or whether throttle or not at this stage after endless mind contortions to try to understand electronics and having thought about the sophistication of the system you need to get a crank drive system to ride really well without downsides of being pinned to cadence so rigidly in higher gears and the likely lack of an electronic power mode selector to regulate the assistance curve without more complexity and cost than is worth it for a 2nd bike.
I already have a bike with a 36v 15Ah battery (which cost over 50% more than I want to spend on a 2nd) and reckon it would max out at about 48 miles if used in high power mode in a pretty hilly (not mountainous) area. That's an absolute minimum need and only just enough to be worthwhile for me. Don't know what sort of controller it has. Peak power after losses of 500W sounds on the light side to be honest. I'm pretty sure my current bike delivers more than that when it's called for and it is rated 250W.
It's not so much 'hill-climbing' over short distances which I'm so bothered about as you can drop the speed and take the time on the chin. It's repeated 3-4 mile steep climbs up steep escaprments where your battery gets completely trashed or else your journey times soar if you drop it down. Currently thinking 20Ah is a minimum, preferably 24. Plus with a crank, really long climbs (same sort of distance) can get knackering if you want to keep your pace up. Not sure how much that's down to power output though (I am just guessing it is) or whether the trade-off of so much battery reduction for a bit more speed is really worth worrying about so much in the end.
Can you not get more power output 'on demand' than 500W after losses from a 250W-rated motor ? The ability to use a full range of gears (say 24 if derailleur or 8-11 if hub) would definitely be preferable.
