Frankenmower front view
OwnerPaul Webb
Owner's Other EV1991 Chevrolet Sprint
LocationNanaimo, British Columbia Canada map
Email email image
Vehicle Champion
Old B&S lawnmower
Motorunknown Permanent Magnet DC
Old computer reel to reel tape drive motor. I think it was rated at either 24V or 50V. Label is worn off after 20+ years in a junk bin.
No Controller, just on/off switch
Batteries6, 72.00 Volt,
Old UPS batteries. Tried 72v but 1 is a dead short so bypassed for now and running at 60v.
System Voltage72 Volts
InstrumentationHand held multimeter
Top Speed4 MPH ( 6 KPH)
As fast as you can push it!
Acceleration0-4 in 1.2 sec.
RangeDid about half my lawn using uncharged batteries and still had plenty in the cells. I figure I can get 1.5-2 hours per charge but only need about 1 hour to do the lawn.
Curb Weight0
Slightly more than stock
Conversion Time4 hours
Conversion Cost$20.00 for the aluminum plate. All the rest was scrounged!
Additional FeaturesI work in the computer industry and collected a bunch of these old tape drive motors 20 years ago. Finally pulled one out last year when I got the mower from my dad with a dead B&S motor. Used a lighter aluminum plate and didn't center it correctly, but it worked at 24v. Rebuilt with better plate and centering and tried it with 4 larger UPS batteries but to heavy and would bog down in thick grass. Did a current check and draws 3.5-4.5 amps while running so went to smaller, lighter batteries and upped the voltage to 72v. 1 battery died right away so just bypassed and ran at 60v and it was an outstanding success.Need a better switch, another battery and some clean up, but nice to replace stinking, noisy gas mower with quiet, cheap electric and no cord!!!
Cost of original mower base - FREE!!!
Cost of batteries - FREE!!!
Cost of motor - FREE!!!
Cost of Aluminum plate - $20.00
Value of cutting grass in a carbon neutral way - PRICELESS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

code by jerry