I believe all 2015 Evo models were 36 volt. Check the label on the pack. It might be possible to have your pack rebuilt to a higher capacity by these folks:I need a new battery for my EVO 27`5 2015 model. The original battery is 48v/417Wh - I would like to replace it with a newer, higher capacity battery, either 500Wh or 600Wh. Will it fit on my bike? If not, is it possible to make it fit?