Electric Porsche – Long time no post

The holidays have come and gone, the snow is still here and the cold weather comes and goes weekly.  Progress has been slow, but a few major milestones have been passed. 

  • The first is a significant change of plans regarding one piece of the build.  The clutch that I wanted to keep so badly is going away, the weight and complexity of keeping the flywheel/clutch/pressure plate swayed my decision enough to get rid of it.  The potential failure of the clutch has been in the back of my mind since I decided to go for the Warp11HV, so instead of designing easy clutch replacement into the motor mounting system, I have decided to simplify things and go clutchless.  After months of searching for a company to build an adapter/coupler for my 944, I was almost ready to build it myself, I have a small CNC mill that makes the adapter plate simple to build, however I don’t have a lathe so creating parts that will spin true at 5000+ rpm isn’t so easy.  Everyone I talked to about creating the parts said I would have to send in the transmission for them to do anything.  If this was a typical car that wouldn’t be a problem, however the 944 is a front engine, rear transmission (transaxle) car, since the engine was never attached directly to the transmission neither will the electric motor.  There is a long torque tube that spins at engine speed connecting the engine/flywheel/clutch to the transmission in the rear.  I offered to send in the bellhousing as well as any critical measurements regarding the shaft of the torque tube but that wouldn’t do, everyone wanted the transmission and they didn’t have a clue how to make an adapter/coupler without it.  After more frustration and searching I was ready to design the coupler myself and have a machine shop create it for me $$$$$.

Then I came across Charlie of evcouplerconnection.com he had already done a few 944 couplers both clutched and clutchless, so he knew what he was dealing with and didn’t ask for the transmission.  After a number of emails and a phone call, I knew I was in good hands, Charlie is a great guy who loves EV’s.  He explained the in’s and out’s of the coupler, how it’s made and how it attaches to the motor, he told me about clutchless shifting and the driveability of the car when it’s done.  Below are a pair of couplers similar to what Charlie is building for me right now.

The coupler uses a Porsche 944 Turbo clutch with the friction surface removed, the splines transmit torque to the drive shaft as they always did, however there is no longer a chance of slipping or wear of the friction surface since it is bolted directly to the aluminum adapter that attaches to the motor shaft.  The final product is much lighter and more compact than a coupler/flywheel/clutch/pressureplatewould have been.  This will allow quicker acceleration and a more reliable transmission of power withminimal chance of failure.  It also eliminates about 35lbs of large diameter rotating mass that simply isn’t required anymore to smooth the intermittent power of a 4 cyclinder engine.  I would highly recommend Charlie for well priced adapters and couplers, go visit him at evcouplerconnection.com.

I will be making the adapter plate that mounts the motor to the torque tube, and I am currently looking at eliminating the bellhousing since the coupler will be around 6″ in diameter at the largest point instead of 11 or 11 1/2″ of the flywheel assembly.  This would let me create a much smaller adapter that would free up a little bit of room near the firewall for the heating system.

  • The second big step was ordering the controller, I finally have a Soliton1 on the way, I was holding off making this post until I could take some pictures of the Soliton1, however Evneticsheld off shipping units until they had solved a small problem related to a new IGBT they were forced to switch to when availability of the old version disappeared.  I’m happy to wait a bit longer and have them tweak the design for the new IGBT, instead of having a product with hardware issues.  Well done Evnetics!  On a side note the Soliton Jr. is now available and shipping from Evnetics so I will add it to the store very soon.  I think the Soliton Jr. would be the perfect controller for mid size cars and small trucks.  It is rated at 500A continuous and 600A peak when water cooled.  It has the same voltage input range (300v nominal and 340v max) and the same features as the Soliton1, this means a maximum continuous power level of 150kw and a peak power in the range of 180kw (est. 200 and 241 electrical hp respectively)  This blows away the good ole Curtis 144v 500A, (72kw peak) that has been standard for so long.

The Jr has the same great looks and features of it’s big brother for a good price.  I’m willing to bet these will pop up in more and more conversions, either by replacing lower end controllers or as a design centerpoint for new conversions.  I think this is the feature rich, powerful controller that the DIY EV market needs to really show others what an electric car can be.

  • The third big step is not directly EV related, but is a cruital step in the finances (LiFePO4 battery) behind the Electric Porsche.  The ’83 944 that I have refered to as the “parts car” is being fixed up to become a daily driver (gas powered) to allow the sale of the Infiniti G35 that does daily duty right now.  This will free up a few bucks that will help fund the Headway cells that will power the Electric Porsche.  The ’83 944 is running nicely now and I have moved on to the interior, replacing the carpet and some of the panels.  There are lots of pieces here and there that need replacing however for a car that’s approaching it’s 30th birthday it’s doing alright.  A distant goal is to paint both cars the same color to have a matching pair of 944’s, one gas, one electric.  I hope to get the ’83 out of the garage once and for all in the next week or two so that real work can begin on getting the electric motor installed and broken in.  So in all the “Electric Car” project has involved removing all of the gas related parts out of one Porsche 944, refurbishing that engine, removing the blown engine out of parts car, installing the newly refurbished engine into the parts car, finding all of the little parts and pieces required to make the electric car run, (electric motor, motor controller, electric heat, vacuum pump, charging and BMS system etc.) finding all of the parts and pieces to put together a slightly mistreated 1983 Porsche.  All by one person in a single garage with portable heaters in a snowy Canadian winter.  But I wouldn’t trade it for anything!


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