After some digging, I found fix-a-flat discontinued its bicycle version of the product because the effectiveness was dismal for tubed tires. Apparently the problem is that a tube "puncture" is fixable while a tube "tear" is not.
I found an alternative product called "Ride On" that does sell a bicycle version. They advertise a similar reduced success rate with tubed tires:

The Ride-On Tire Protection System (Ride-On TPS) is a revolutionary line of tire sealants that prevent flat tires, seal leaks and punctures, balance tire/wheel assemblies for the life of the tire, extend tire life and reduce downtime associated with tire failures. Ride-On Tire Protection System (TPS) tire sealants will eliminate 85-95% of your flat tires in tubless tires. Ride-On tire sealants' efficiency in tube tires is reduced to 55-65% since puncturing objects often tear the tube. Ride-On TPS tire sealants are great for cars, light trucks, SUVs, RVs, motorcycles, scooters, ATVs, bicycles, skid steers, lawn mowers, etc.

8-oz. bottle of Ride-On TPS tire sealant for bicycles (Bike-On Formula), valve core removal tool, and installation hose. Each bottle contains enough Bike-On to treat two bicycle tires. Bike-On is formulated for use in tube and tubeless bicycle tires (not for Presta Valves). Bike-On tire sealant (tyre sealant) is formulated for use in tube and tubeless bicycle tires (not for presta valves). Bike-On seals most tread punctures up to 1/8" in diameter, prevents flats and helps tires longer. Bike-On contains corrosion inhibitors that protect aluminum and steel wheels against oxidation. Bike-On also helps reduce dry rot and the tiny invisible porosity leaks that cause tires to deflate over time.


$6.95 pr bottle
http://www.ride-on.com/prod_bike-on.asp

For the OP's electric bike which is virtually impossible to repair roadside, this may be a possible solution.