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"New" EV: 1973 Saab Sonett Conversion

113527 Views 121 Replies 20 Participants Last post by  Aethora, 
M
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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
http://www.diyelectriccar.com/forums/showthread.php/re-using-complete-leaf-drive-system-151458.html
- Removed outdated 96V DC PbA based system from Sonett
- Sonett teardown to frame nearly complete

Plans:
- 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.

Original Post:
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 :)
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M
Had to travel for work last week, but back at it again. Finished preliminary rewire of front left/right packs into clone of rear pack. Turns out I'm missing some of the spacers needed to fully assemble, but had enough parts to wire it up temporarily to figure out how to do the bms wiring. What I ended up doing was labeling each BMS terminal connector with the cell # before dissembling the left/right front packs. Then took them apart, and reassembled the cells into the correct +/-/+/- order for the rear pack bus bars. Then I snapped the bms terminal connectors onto the new locations based on cell number. Its a bit of a stretch at the plug end, and I still have to figure out how to manage the wiring and hookup at the higher level. But, this should allow me to use the existing right/left front pack BMS looms completely intact, which means they are already pinned out correctly at the connectors to plug right back into the bms harness. Not having to do any cutting/splicing on this harness is a big plus given the shear number of wires involved, and the risk of damaging the bms if there are any mixups. I was able to test the cell voltages at the bms harness connectors LB7/8 and everything looks good, so I'll still be a little nervous when it comes time to hook it back up but it should be good to go for a test back in the Leaf soon. I don't want to have any significant charge/discharge without the spacers properly in place to keep the pack in compression, but I think I should be good for a powerup test soonish. Then I just have to find/make the missing spacers :/

Rob
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M
Ok, so reading a little more, it seems like the Leaf modules are not compressed in the pack. If anything the spacers keep a little gap between "cans" which may help with ventilation.

Rob
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M
Back up on jack stands, seats out, floor covering coming out next. Need to cut a hole on the passenger footwell to pass the HV connector into the passenger compartment so I can temporarily reconnect and test the rewired battery.
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J
Great work!
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6
Thanks for refreshing my memory :)
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M
Floor is out, ready to start cutting :)
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L
For the record, I absolutely love how well you're documenting this. When I get around to mine, I'm going to be doing similar.
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M
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Coming along, should get the Leaf back on the road for testing this weekend if all goes well.

Hole cut in passenger footwell to allow HV connector to pass inside and connect to battery contactor box, front seat and shifter / ESC controller, parking brake control reinstalled.


Getting the two 200+ lb packs back inside the car was a lot more challenging than I had figured. I will likely remove the doors and clear out more space in the garage when removing so I can get get clearer access with the shop crane. I guess I can always cut the roof off too if I have to ;)


The newly assembled pack without spacers and side brackets is also a lot less rigid than I would have guessed. I'm planning to add spacers, and have figured out that I can cut the end tabs off the left/right sub-pack top plates to make up the spacers I'm missing. Hopefully that will be enough to increase rigidity. Adding the side rails will be tricky without the special spacers that include the mounting bolt ears.

Rob
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Also I won't really be able to re-use the rigid bus bars that made up about half of the internal HV connections, but fortunately I had some old lengths of 0000 gauge wire with lugs already crimped on lying around that I had rescued from a scrap yard years ago. Overkill, but will do for now ;)

Rob
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M
Well, looks like I managed not break anything! :)


Everything powered back up fine, no new DTCs, went to D/R as normal, charge initiated as usual.

Rob
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J
I love it when a science experiment comes together! So let me get this straight, you could possibly (save for the BMS trouble) put another Leaf pack back in the stock location and have a double range Leaf now.... things that make you say Hmmm.
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6
Wow Rob, you have done a fantastic job and I likes the level of labeling you have done.
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M
Thanks 67BGTEV, I'm probably being overly paranoid, but once I pull everything out of the Leaf I want to make sure I know how to hook it back up ;) In general I'm pretty impressed with the Leaf wiring harness though, they really seem to have gone to pretty great lengths to minimize the risk of that by using unique connectors at almost every junction I've encountered so far. After I've done some more testing of disconnecting various controllers/systems in the Leaf, I think my next task will be to try and reproduce something like your pegboard demo :)

jwiger, I think its very possible. As you say the challenge would be the BMS, though if people have gotten the BMS to work with the battery outside a Leaf it could be possible. You'd have to isolate the second BMS on a separate CAN bus with a controller programmed to feed it the right info, and combine the appropriate output messages of the two LBCs to preserve the safety / fault systems. Another approach would be to wire the batteries in parallel on a module by module basis in which case the BMS should continue to work as intended, now its just monitoring 4 cells in parallel per tap instead of 2 as it does normally. The unknown is how exactly the LBC/BMS would respond to the increased capacity, but given that it already appears to use a dynamic estimation of total capacity it seems like it should "learn" over time that the capacity is increased and allow more range. With 2x the capacity its possible that some of its calculations could overflow the number of bits available to track capacity, someone would really have to try it to find out. If that's an issue, this could also be done with 1/2 a battery to increase capacity by 50% by using each of the four cells per module independently but that would require opening up the modules and more significant rewiring.

Rob
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D
Rob,
I'm curious where you got your shop manual. I picked up a 2015 "Run and Drive" from Coparts in Portland. It does run and I can drive it but it's kind of like a clown car - the right front tire is definitely out of round. I would like to have as much info as I can when I start to cannibalize parts for my conversion.

Thanks,
Bill
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M
Hey Bill, congrats on your Leaf! I've been using a copy from the Nico Club:

http://www.nicoclub.com/archives/nissan-leaf-factory-service-manuals.html

Rob
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After asking the question, I did some poking around on the 'net (via Google) and ran across the Nico forum and a couple other places. It looks like the '15 manual isn't available yet. I'll probably have to settle for the '14 and hope for the best.

Thanks for being a trailblazer.

Bill
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M
Thanks Bill, best of luck!
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M
BTW, here is a video I shot last night documenting the state of the Leaf disassembly and showing the location of the major components in the Leaf. Planning to shoot another similar video once I have everything out, hopefully in the next week or two.

https://youtu.be/8OBHiTLkANc

Rob
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dedlast said:
After asking the question, I did some poking around on the 'net (via Google) and ran across the Nico forum and a couple other places. It looks like the '15 manual isn't available yet. I'll probably have to settle for the '14 and hope for the best.

Thanks for being a trailblazer.

Bill
Click to expand...
BTW my understanding is there is a site where you can download the service manual directly from Nissan for $20. Not sure if they have the 2015 up yet though. The 2014 is probably going to really close though.

Rob
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FYI I've documented two new findings in the "re-using complete leaf system" thread:
http://www.diyelectriccar.com/forums/showpost.php?p=635905&postcount=24

I've disabled both the ABS controller and the EPS (power steering) controller with no apparent issues aside from DTCs and the loss of the associated functions. Vehicle still appears to run and drive fine without those controllers connected.

Rob
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