1954 Solar-Powered Farmall Cub


     For further information, also see Appendix 7 in the book, The End of Fossil Energy and The Last Chance for Sustainability, by John G. Howe. Send $10.00 (includes shipping) to Howe Engineering Co., 298 McIntire Road, Waterford, Maine 04088.

     This Cub was built 50 years ago to replace a team of horses, mules, or oxen at a time when oil and gasoline became plentiful and inexpensive.  A team of working animals needed 20,000 pounds of feed per year plus considerable attention and care.  Now the world is at the peak of available fossil fuels, oil, natural gas, and coal.  Supply shortages and higher prices are imminent, and in 50 years fossil fuels will be very expensive and possibly unavailable.  The world will need alternative energy sources especially for growing food.  Hydrogen is not the answer for alternative energy because of the vast amount of energy required to produce it as well as storage problems.  Available crop land will be needed to feed humans, not draft animals or production of biofuels, which require considerable energy input and soil depletion.  This solar-powered Cub was retrofitted in 2004 as the first in a series of vehicles to ascertain the validity of solar-powered agriculture and transportation.  This same tractor was later featured in the Aug/Sept 2006 issue of Mother Earth News., under the subheading “The Little Cub that Can.”

Tractor Specifications:

Continuous power: 7.5 kilowatts, 80 Amps at 96 volts (10 Hp) ... strong enough for several hours of light plowing or to pull a 6-foot, double-disc harrow.  This is similar to the power of a team of large draft horses or 100 humans at 75 watts each.

Battery pack: Eight combinations of 220 Ah (150 Ah at 75 Amperes) deep-cycle batteries providing two to six hours of typical power without solar recharging.  The batteries are continuously recharging as long as there is sunlight. An added half-ton capacity trailer could have an equal array, doubling the charging rate.

A tractor for modern, pollution-free agriculture

as the world runs short of fossil fuels

Weight: 2400 pounds including driver, on-board solar array, and 1000-pound battery pack.

Gearing and Drive Train: The solar-powered Cub uses a 1.6:1 tooth-belt drive from an Advanced K-91 motor driving through the 1:1 PTO shaft.  The clutch to the gasoline motor is blocked out unless needed to rotate the hydraulic pump.  A hydraulic disk brake on the input shaft eliminates the dangerous braking problem common to free-wheeling electric drive vehicles.

Recharging: The Cub needs about 20 Amps (2.5 Hp) to power itself in soft ground.  This makes the 5 Amp solar input significant enough to justify the on-board, four-panel array.  This is especially true if the Cub is used for light, sporadic work, to charge other vehicles, or supplement residential PV systems.

Work Capacity: The Cub will provide up to 5 Hp for light 12" plowing or pulling a six-foot, double harrow in previously tilled areas.  The total power requirement of 7.5 Hp is a drain of 5Kw or 55 Amps.  The battery pack will provide this power for over three hours or enough to plow ½ acre or harrow a smooth one acre.

John Snyder, Mother Earth News

The Cub pulls a double disk-harrow with ease.