Yeah you should reinvent the wheel while you're at it and 60 pounds of SLA batteries is a pretty good idea too.
Why do you think 99 % of anybody with an e-bike uses lithium ion or LiPo batteries. The brushless controller below is $29. It's also 1500 W 45 A, and 48 to 84 V range. It has regenerative breaking, regenerative charging, reverse, cruise control and it is also a smart controller that will configure itself to your phase angle and order. Not to mention LVC circuit protection and other gadgets you can use for displays or lighting.
You also have to ask yourself just how would reverse work on a bicycle? My average speed on my bike is 32 miles an hour. Sending an improper signal to reverse in attempt to the slow the motor down, would send you over the handlebars and shred your forks beyond repair.
Here's the link to that controller:
- GREENTIME 15 Mosfets 48-84 V 1500 W 45 Amax Dual modus Sensor/Sensorlose Bürstenlosen DC Motor ControllerGREENTIME 15 Mosfets 48-84 V 1500 W 45 Amax Dual modus Sensor/Sensorlose Bürstenlosen DC Motor Controller
Along with some links to some forums that specialize In E bikes: