Those 1500w motors are direct drive rather than geared hubs. As such they are renown for being very heavy on batteries. At low speed or on hills they are inefficient and will turn a lot of power drawn from the battery into heat. So good only on flat rides with little stop start and at speed. The battery needs to have top quality high amp cells and a maximum current capability of 1.5 times the maximum current delivery of the controller in order to avoid voltage sag and cell damage.
To run two motors you will need two controllers making the battery even bigger/heavier.
Now, lets mention legality, 'cos if I don't someone else will. A 1500w motor is not legal as a pedalec and, because of physical size, is impossible to diguise. The speed at which it will run will also make it illegal. To be legal it would need to be type approved, registered and insured as a moped. It would still be limited to 15.5mph and you would need to wear a motorcycle helmet and ride on roads only.
Two motors is just plain illegal, no wiggle room.
Given the weight of the battery and motors and the speed/power you're after, why not just go and buy an electric motorbike?
