Some limited information from the GEM factory:
http://www.polaris.com/en-us/gem-electric-car/pages/owner-manuals.aspx
The 2004 and prior service manual can be found here:
http://greentechfusion.smartlivingguides.com/wp-content/uploads/2012/10/Gem-Car-Manual.pdf
http://www.notepad.org/GEMcar/Gem%20Car%20Repair%20and%20Maintenance-Service%20Manual.pdf