Boyntonstu said:
It seems to me that a step through womens bike is a better platform to mount batteries.
Scooters do not use triangles and are pretty rugged.
A front end like on this trike comes to mind.
http://www.sears.com/schwinn-meridi...830?sellerId=10149701&hlItemId=SPM11514198830
Link didn't work because of european IP so didn't get to check out the trike you linked.
Most or at least many Scooters uses 2 tubes side by side with braces in between from head tube backwards. That makes them rugged. A typical womens bike uses one tube bent to an S shape or even 2 tubes o/u to make the S shape. The latter is strongest. But hard to fit batteries.
If you make a frame like a scooter you could have an easy to step into bike and maybe even fit all the battery you need "under the floor board".
Good low gravity, easy to use in town, usable for all riders even elderly riders, or people with some handicaps. In many countries in europe those scooters are ridden with 2, 3 or even the whole family and bags of groceries. Those frames handle 400-500 lbs of rider weight with ease.