Issues Testing an Imperial Electric Permanent Magnet Motor

I've come under the possession of 3 Imperial Electric motors:

Model: P66LR006

Volts: 36 VDC

Amps: 100

HP: 1.3

RPM: 2100

Before selling them I've been trying to test their function. I have three 12 VDC batteries that I can wire in series to obtain the 36 VDC but want to make sure I'll be doing this correctly.

My questions relate to the DC voltage mostly.

#1: Since I do not have the controller for this motor (came off a floor scrubber) would the best way to test this be applying a lower amount of VDC and slowly ramping it up to 36 VDC? What type of electrical device in series with the batteries would be able to do this?

#2 These motors ask specifically for lead acid batteries. I'm not very familiar with testing electric motors in this way. Would a car battery be a bad idea to utilize in the testing method? Do Crank Case Amps have any negative effect on a permanent magnet motor?

Obviously I need to learn more about DC voltage in relation to electric motors and any help here is much appreciated. Thank you.