Open Source Civic EV Kit: Ordering a Motor Adapter

After some significant debate at the Civic-EV Google Group on whether to use a clutched or clutch-less system, I'm going to pursue using a clutched system for the initial revision of this kit.

Here are some points I considered:

Clutched system for Civic:

feels more like the original manual transmission, allows people unfamiliar with EVs to drive it more easily; downshifting much easier
Allows troubleshooting of the drivetrain by allowing an intermediate disconnect point during operation
Adds a safety feature if the controller shorts and over-revs the motor
inertia from heavy flywheel slows acceleration
clutch slave cylinder interferes with placement of front golf cart batteries but not Deka 9A31s

Clutch-less system for Civic:

much less mass to spin up during acceleration
shifting is a bit slower as the driver uses the synchromesh to spin the motor down and up
shifting can only happen while the accelerator is not pressed
clutch slave cylinder doesn't interfere with 8V golf-cart batteries
this system still uses the springed center of the clutch disk to remove stresses on the drivetrain from bumps

With the clutch-less system, I would have had to order the shaft adapter from EV-America and then machined the outline for my own transmission adapter. With a clutched system, I just order the shaft and transmission adapter from Electro Auto and everything is just done. While the design of the shaft and transmission adapter is not open-source, there are many other parts (like the DC motor) that aren't open-source as well. Perhaps in the future, I can make an open-source adapter design, but I've found that the money saved in machining one's own adapter is small compared with the hassle of getting a local machine shop to do the job right.

For those of you wishing to make your own Civic-EV, Electro Automotive will ask you for the bolt pattern on your flywheel since they've had problems with Civic adapters in the past. Here's a picture of the bolt pattern I scratched from a purchased Civic flywheel. The resolution is 300x300 dots-per-inch. If you print this out using MS-Paint with the proper 300x300 scaling, make sure it exactly matches the bolt pattern on your flywheel before ordering the adapter from ElectroAutomotive.

Remember the transmission I pulled out of the Civic at the wrecking yard? I cleaned it up so I could get some measurements on it for the clutch-less system. I can verify the ElectroAuto adapter on this, but I won't need to measure it anymore since I'm not considering the EV-America clutch-less system for now.