From the vault: 1979 Briggs and Stratton 6-wheel hybrid

We know that the idea of hybrids is not a new one by any stretch of the imagination. Ferdinand Porsche (the original) built what may have been the first hybrid over a century ago. A little closer to home a company better known for lawnmower propulsion created an American hybrid in 1979. Briggs and Stratton wanted to demonstrate that a hybrid could be built largely from off-the-shelf parts. They built up a six-wheeled plug-in parallel hybrid using an 18hp garden tractor engine. The engine was combined with a 8hp electric motor from a company that makes drives for treadmills. The dual rear axle configuration was needed to support the 1,000lb lead-acid battery pack supplied by Johnson Controls. The pack could drive the car up to 30 miles around town, but their wasn't really enough power for highway use where it would struggle to hit 50mph uphill. The car could even run on ethanol. The $300,000 prototype now sits in the Briggs and Stratton company museum in Milwaukee.

[Source: Milwaukee Journal Sentinel, thanks to Adam for the tip]