What size invertor?

I used to have a 24 volt scooter with a 2 amp charger, and used either a 150 or 300 watt portable inverter that plugs into the cigarette lighter.

I would suggest a 300 watt MSW inverter - Modified Sine Wave. You do not need the much more expensive pure sine wave, it will work fine with MSW.

I have bought a 500 watt Coleman brand MSW inverter at Costco for $30, but they do not sell them there anymore. Auto parts stores, or Amazon.com have a lot to pick from at $25 - $50 range.

I would run a dedicated cigarette lighter receptacle to the area where you will be storing the bike, or perhaps under the awning in the storage compartment like I did. I used #10 wire and a 20 amp fuse, allowing up to about 200 watts output. I ran #10 wire to both the + and - not using the steel frame as a ground, it seems to have less voltage loss that way.

Good luck!

Fred.

I would stick with Pure Sine Wave.

I would try the 300 watt inverter.
41.5 x 2 is just 83 watts... doubt it would draw more than double.

I suggest at least 2 x 41.5 watts.