Rite I want to give my fiido some more grunt to use on private land , it has a m12 size axle wirh a 175mm drop out now as present it runs 500watts is on 20x4 rims by the looks of it il have to for a battery to top of frame and do away with existing one inside . Get rid of the controller etc any ideas as only ones I’ve seen are kirby ebikes 1500 watts but looking £900