Luther Rd looks around 15% for a 50m section on OSM and the worst Ipswich has to offer
Is anyone acquainted with it to confirm or otherwise? Saneagle's favourite AKM128 would be half the weight of a Bafang kit.
The OP wanted a bike which isn't rear heavy. The AKM128 weighs 2.8kg - unsure if it can be installed on a Brompton (135mm dropouts required), or if that would make whichever lightweight bike she got converted too rear heavy, like the OP's present rear motored and batteried Crusa is.
One thing to remember os that Katy at 70kg is probably a lot lighter than you guys, so she will require less power, I'd be surprised if she used over 15wh/m in total, which means a single 600wh battery should be OK for 40 miles as long as she can do some pedalling.
I weigh 68kg now, the OP is heavier than I am. I weighed about 70kg when I rode my BBS01B conversion with 19.2Ah/691Wh battery for 43 miles, with the controller limited to 15A, consuming 16Wh per mile. I was carrying a laptop, tablet, DSLR camera, lenses, photography lights, camera and light batteries, two tripods (one carbon fiber), phone, powerbank, plus other stuff. The only time during that journey the motor wasn't doing nearly all of the work, was when I had to sprint ahead of traffic at 21mph when three lanes suddenly became one, because of roadworks, which was when I was grateful for my 52T chainwheel. On a 16" wheeled BBS01B Brompton conversion travelling slower than I usually do, with gearing more appropriate for hills, I think the OP could get away with the BBS01B controller limited to 14A or less, and still have a bike with the same or similar excellent hill climbing ability as mine, and more range from the same 19.2Ah/691Wh capacity battery.
