Bump to this old thread. Went out to give the 3 Wheeler its monthly start and it seems the cold has left the battery too flat to turn her over.
I have a trickle charger (and jumper cables) but upon reading the M3W handbook under section 14 jump-starting, it says to secure the negative "to a good earth on the chassis." Being that the chassis is powder-coated, where would this location be?