Can I leave my GEM on a charger for a few days?

I have a 2002 GEM and sometimes I don’t drive it for a few days. Is it ok to keep it plugged in? Will the onboard charger control the charge of the battery and shut off when the car is fully charged?

Assuming you have lead or gel batteries, it wont hurt your batteries, but it wont help them either. The OEM charger for a 2002 is the Zivan NG1. It does not have a trickle charge / maintain feature. Once it reaches full charge, it will shut off and stay off. There are a few eprom upgraded NG1 out there that have a 7 (10?) day auto reset, where they are supposed to kick back on after that time. If you trust it. I’d use a heavy duty wall outlet timer if i lwft it in that long.

Other brands of chargers behave differently.

yes, my uncle had the same situation as soon as there was a full charge - it turned off