Exactly so, and in spite of the whingers on here blathering on about "illegal" bikes, I have no desire to slam 48 or even 72 Volts through my motor (it will take it, others have done so). No, 26mph is plenty fast enough for me on a 20 year old MTB, for the fact of the matter is, with my duff knees all I'm really using the bike for is toodling down the nearest village and into the nearest small town for occasional bits and pieces - hardly scaring the children or horses (I leave that to those over on ES )I can connect 2 batteries in series to get 72V and something over 40mph by upping the the controller to 40A (peak performance at 72V /65A is about 45mph).
I've not tried all 3 batteries in series (108V)- even 36V gives all of the performance I need. The controller is programmable and covers 36V to 110V and up to 65A (beyond if I beef up some of the solder tracks) but I didn't get it to be a racer, just capable of travel without any added assistance whenever needed and 36V/30A gets me up any hills and against any headwinds I've come across.
What the moaners fail to understand is that my bike is suited to me - speed isn't the issue with me, it's the ability of the motor to get me up to a reasonable cruising speed and keep me there without pain. If I want to go fast, I've got three motorcycles in my workshop - two 850s and a 650, any of which will do that. I long since got the speed bug out of my system; these days its just about getting there in comfort and a bit of pleasure.