We use a charger that produces 7 volts DC at 700 ma, Output connector is 2.5mm x 5.5mm female center positive. These chargers are custom made to our specs. It will be difficult to find this charger exactly to these specs. You can use a 6 volt DC charger in a pinch (any ma current but must be center pin positive). It will not fully charge the battery so you may experience a machine that does not pitch up to full speed.Any questions, contact us here: https://contact.maxbp.com/