[AndrewJ]

Are you going to keep the 48v setup for the extra range or are you reverting to 36v?

Too bad the 28c won't fit. Is a 25c tire an option? I had a 25x700 Bonty Hardcase on my singlespeed and I loved it.
I got it after a piece of glass in the bike lane ripped through the sidewall of my old tire, from the center of the bead clear to the rim.
That was one fast loss of pressure...

Anyway,
This gets me thinking...
Do you have enough clearance at the fork crown to run a 28c tire up front? You could put the batteries up front in some lowrider panniers. Your front tire has less weight on it in the first place, so putting the extra 30lbs up front makes sense to balance the load.
And putting it in lowriders lowers your center of gravity.
And you'd get your batts closer to the hub and controller, shortening the wire runs.

Just a thought.