Mower conversionMower conversion rear viewmower dashboardEngine compartmentPulley shaft
OwnerAl Latham
LocationChimacum , Washington United States map
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Vehicle2000 Sears Craftsman 16.5 hp 42
Craftsman 16.5 hp gas, 42" cut riding mower
MotorBriggs and Stratton Etek Permanent Magnet DC
Etek permanent magnet dc motor (brush type). 8hp continuous, 15hp maximum; 3450 rpm @ 48 volts.
DrivetrainStock belt drive transaxle. Adapted engine pulley shaft on gas engine to Etek motor.
No controller needed. Gas engine ran at 3600rpm, ETEK motor runs at 3450 rpm @ 48 volts. Lawnmower engines run at full speed all the time.
Batteries4 Interstate SRM24, 12.00 Volt, Lead-Acid, Flooded
2 mounted in engine compartment, one forward & one aft of motor. 2 mounted in plywood box mounted on rear of frame.
System Voltage48 Volts
Yamaha 48 volt two stage golf cart charger 17/13 amp output. Powered by off-grid solar power system through inverter. Charges in about 3 hours.
DC/DC Converter None
Instrumentation48 volt LED battery fuel gauge/battery meter. Shows state of charge. Not really needed as you can tell that it's ready to stop mowing when the blades slow down!
Top SpeedApproximately same as with stock gas engine.
Accelerationnot a neck snapper!
Range1 Miles ( 1 Kilometers)
Mows medium thick grass for 45 minutes. Mowed 1 mile of driveway edge and it could have gone further.
Seating Capacity1 adult
Curb Weight0
Etek motor 22lbs. Batteries 184lbs. About 114 lbs. heavier than before conversion. Weight increase not noticeable and well distributed.
Tiresstock riding mower
Conversion TimeCouple of weekends
Conversion Cost$830 for motor, batteries, circuit breaker, meter.
$192 for battery charger.
Conversion will pay for itself in approx. 1 millennium!
Additional Features250 amp Airpax circuit breaker used for over current protection and on/off switch.
Box added on rear of mower holds 2 batteries.
Thanks to Carl Ervin WebPage for inspiration and sharing information on his similar conversion. Carl's entry indicates that the draw is 5 amps in neutral, 70-125 amps avg to high grass. Max he's seen is 150 amp draw.
Stock engine pulley shaft w/drive and mower pulleys from gas engine used. Gas engine had 1" shaft diameter, Etek motor is 7/8". Randy, CEO of Eaglemount Marine & Salvage, constructed shaft adapter/extender to mount pulley shaft on Etek, and made steel motor mount adapter-Thanks!
One has to be careful to mount pulley shaft so its located in the same location as it was on gas engine.
Lots of power and cuts through tall grass with ease, at least as well as gas engine, perhaps better. Sharper the blades the longer it mows.

code by jerry