John, or Eric,
Something that I've always thought could be done better is that door hinge actuated, normally-closed switch for turning on the BCU and BMS charging. A failure of the switch lever mechanism or the door hinge (which holds the switch open) when the scooter is unattended or in storage would leave the battery pack slowly discharging.
Sure, it would take a long time - about 25 days - to discharge the battery pack completely flat, but we are talking a probable ruined battery pack if it does happen - a similar situation to a car's engine being ruined if the dome light is ever left on. A better fix is to have the charging circuit actuated only when the charging cord is actually plugged in.
So, I am thinking about replacing the door switch with a relay actuated by the 110 volt mains. Since I have a timer switch for the charging outlet in the garage, this provides a "plug and forget for days" solution. Would there be any technical issues I may need to know about before doing this?