Saturday, June 11, 2011

Introducing the 48 Volt Vegan

Long-time followers of the Karmann Eclectric may be familiar with our protagonist's propensity to pursue diversionary projects well before completion of the mission at hand. Well, once again, a fortuitous turn of circumstances presented a long-desired opportunity that was too good to pass up. Being in possession of a full acre of suburban bliss, we found ourselves disturbing the peace with somewhat regularity due to the requirements of lawn care, and the dominant paradigm of closely-cropped lawns via infernal combustion.
So, the only way to stay in good standing with the homeowner's association, reduce my fuel consumption, and create the coolest mower on the block would be to convert one. Not wanting a run-of the mill electrified piece of Crapsmanship, I'd been watching the exploits of both the US Lawn Mower Racing Association, and learned that most modern lawn tractor transaxles simply can't handle serious power, and then joined the followers of one of the most durable lines of garden tractors ever made, Simplicity. It so happens that the Sumner High School Auto shop received the donation of an orphan Allis-Chalmers Big Ten, vintage 1965, but couldn't get it running, and the local EV Expert Tim Ritchey had on his hands an engine-less twin to the Big Ten, a somewhat later Simplicity Sovereign. Why involve two tractors? Well, one has a pristine mower deck, and the other a stout functional tiller. Put 'em together, and Sumner High can have the homecoming float tractor that they desired, and I can have a killer, combustion-free, competition-ready, true Garden Tractor.

Here's our twin victims...
You'll notice the family resemblance, they share the same frame, but some cosmetic, cost-based, and slight mechanical changes were made over the years....

So, business buddy Eirik O'Neal came over to help begin the conversion last weekend, and we made good progress, verifying that a 6" Advanced DC acquired in trade with the EV Expert had a matching shaft to the decommissioned Briggs and Stratton horizontal shaft engine. We penciled out the dimensions of a required adaptor plate, and generally familiarized ourself with the tractors, selecting the Simplicity as my tractor, due to both it's clearer title status and narrower cowl, which would simplify battery placement. The Allis Chalmers mower deck should transplant nicely...
Here's the first mock-up with motor.

The next weekend, there was a change of cast, and Dean West came over for a turn on the Vegan. He and I mounted a 'proof of concept' wooden motor mount, and good neighbor Tom happened to have a woodruff key that matched the motor! We got it installed and aligned as well as we could, running the motor on 12V to fine-tune it's alignment and eliminate vibration. Once the motor was mounted and shimmed, it was time for a test drive. We knew from a hot jumper cable that it was pulling too many amps on 12V, so quickly rigged a 24V pack, and prepared for an inaugural test drive on electric power- Frankenstein Style, complete with a gawker gallery.