A compact battery powered mover for heavy rollable loads, having a ventilated battery compartment incorporated into the body of the mover and a removable rechargeable ventilated battery that permits the replacement of a spent battery with a fresh battery at the work location. The mover also has incorporated into its compact design a motor controller that enables the use of a heavy current draw when needed for brief periods without developing excessive heating. The configuration of the critical components in and on the mover body permits the substitution of one critical component with another component having different operating properties without significantly changing the compactness of the mover.