1973 Saab Sonett Conversion w/Nissan Leaf Drive System
Status Update 1/12/16:
- Obtained a running/driving salvage 2012 Nissan Leaf
- Completed Leaf teardown, demonstrated system functioning outside the Leaf
- Removed outdated 96V DC PbA based system from Sonett
- Sonett teardown to frame nearly complete
- Make more accurate measurements of Sonett frame, and Leaf components to finalize placement and fabricate necessary mounts and brackets.
- Initial focus will be to make bare Sonett chassis drivable / functional for continued testing of Leaf Drive System re-use.
- Phase I will likely be similar to Leaf tabletop demo, retaining Sonett brakes, hubs, and steering with modified drive shafts to adapt Leaf transaxle to Sonett hubs. Components from Leaf to include Motor, Inverter, VCM, BCM, DCJB, On-Board Charger and Charge ports, Shift Control, Power On Control, wiring harnesses (inc 12V fuses, relays), liquid cooling system, some display and control instrument / switches.
- Phase II will likely aim to fully enable regenerative braking, may incorporate Leaf braking system (master cylinder, brake controller, ABS controller, calipers, parking brake controller), hubs and wheel speed sensors (preferably in modified Sonett knuckles to avoid suspension changes), possibly adapt steering sensors and electric power steering.
- HVAC and other creature comforts (audio, door locks, Nav, Telemetrics, electric heater) will probably be incorporated throughout phase I and II as practical / convenient.
- Final phase will be to work on restoration / cosmetics once function and fitting of components are complete.
Well, after about 10 years of EV dreaming, I finally took the plunge
I've always had a soft spot for these odd-ball Saab's, ever since owning one (that I could barely keep on the road) back in the late 90s. When researching platforms for a conversion, I was rather pleased to discover that they seemed to be an excellent candidate. With a curb weight of 1800 lbs, a Cd of 0.31, and a miniscule cross sectional area (22% smaller than 1st Gen Insight), they were fun to drive with the stock ~60 hp engine while averaging 30-35mpg in a day when 10-15mpg was typical. They were also designed as racers, being proven as a great platform for performance enhancements and doing quite well in their SCCA and rally classes.
I wasn't planning to start my search in earnest for another month or two, but when this example came up for sale locally, I couldn't say no
It was about the same price that I would have spent on a fair condition runner in need of complete restoration, but had already had a simple DC conversion done in the 90s and a significant amount of work had gone into restoring the frame/floorpans and mechanicals as it passed through the ownership of two different vintage Saab restoration gurus. If nothing else its a great rolling chassis
to build on, with a bonus that the old conversion has been maintained and rebuilt well enough to still be used as a commuter in the mean time.
The conversion is definitely a bit of a time capsule from a bygone era
From what I gather it was based on a kit from either EV America and/or Solar Car Corp in FL with a custom adapter / coupler designed by Saab Quantum designer Walter Kern to the original 4sp freewheeling transmission (used clutchless). It uses a 6" GE Series Wound DC motor (looks to be the 11.6HP commutavan motor) with forced air cooling, a Curtis 1221B-7401 controller set for 300A max, and a 96V flooded lead acid pack. Looks like it was originally set up for 16s 6V batteries, but changed over to 8s 12V at some point. Have to start in 1st gear to get it rolling, then 2nd will do just about everything except freeway speeds. Haven't tried that yet
It seems like its gone through several incarnations, mostly reusing the original components. Original conversion was done '92-93 by Bud Clark of J&B Imports in CA following Walter Kern's design. System was removed and significant restoration of floorpans and mechanicals was done in 2009-10 by Jack Ashcraft in OR. Motor and Controller were rebuilt by subsequent owner in 2013, and funky split 55V chargers were replaced with a Delta-Q unit in 2014. 5/8 batteries are Trojan T1275s from 2014, 3/8 are US 12VXCs from 2009 that are getting pretty weak. Still good enough to drive it 13 miles home on surface streets and come to rest at 12.2-12.3V though (vs. ~12.6 on the Trojans).
I'm planning to get those last 3 old batteries out of there, and add some instrumentation (probably cycle analyst and a modified Celllog 8S) and keep using it for my daily 15 mile RT commute while starting plans for a major update