I am generally happy with my two bafang BBS01 250watt powered ebikes, BUT i would like more horsepower. When i can afford it, I will get either a BBS02 750Watt or a BBSHD but both of those require 48 volt batteries. So can i upgrade my batteries to 48 volt now and run my BBS01's on them, or would that burn out the controllers? Or is it possible to upgrade the controllers so as to take the higher voltage. Any advice greatly appreciated especially from someone who has already done a similar upgrade.