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Old 09-04-2012, 02:47 PM   #47 (permalink)
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Originally Posted by NeilBlanchard View Post
The folks at Illuminati Motor Works would tell you not use a clutch. They (probably) would have won the X-Prize if they had not used a clutch. They just use the car in either 3rd gear (better acceleration) or 4th gear (about 2% better efficiency).
The clutch/no clutch debate is hotly contested on DIY EV forums. The arguments never seem to mention efficiency, because clutches are pretty well 100% efficient (when fully engaged). The only inefficiency may be the added inertia of the flywheel and clutch assembly that may hinder acceleration a tiny bit, but since this isn't the X-Prize, it is probably irrelevant.

The "pro-clutch" people seem to like clutches not because of shifting (although it is a nice bonus to be able to shift normally), but because of the added safety measure - being able to disconnect in the event of a runaway. (The event that will change your pants from green to brown in about 2 seconds).

If you have the skills to incorporate a clutch, then I advise taking that route. If not, then the no-clutch route is simpler and easier and nearly as good, just as long as you make sure your HV system has plenty of safety redundency in case of the dreaded runaway.
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