Ev crx
 

Honda CRX

http://images.craigslist.org/00n0n_k...Tu_600x450.jpg

Clean CRX, looks like a pretty nice conversion. Definitely needs more info though.

20 mile range... wow, that sucks.

Yeah. And those batteries might be the explanation. They seem like big lead acid batteries, no? Heavy, bulky, and not much energy storage.

This looks much like most home/DIY conversions done since the 70s. A 20 mile range works for many people, but yes with the advance of liPo batteries things are changing.
I for one am only aiming for a 40 mile range in my conversion because I rarely drive more than 30 miles a week, with the occasional 30 mile day.

It would be very easy to rip out those lead acid batteries and throw in some lithium cells. Get a new charger (or possibly reprogram the existing one), add a BMS if thats your fancy, and you could have 100 miles of range or more.

And a new motor that has more than 10 hp?

A 10hp motor can push a LOT more than 10hp through it, it just can't do it continuously. That motor would probably have no problem putting out 100hp until you hit the speed limit.

I wonder how efficient this pairing of an electric motor with the stock transmission is relative to systems designed specifically to be electric. Is there much of a difference? Does this little car lose some of its possible range to an inefficient transmission pairing?

That is a complex question, but almost guaranteed the transmission helps efficiency. It certainly helps acceleration. DC series wound motors like that operate at higher efficiencies based on rpm/amp load. Also, batteries like lower amp draw (as do the electronics), so you can keep rpms higher and treat them nicer which will extend range as well as battery life.

So if I understand, you're saying that the transmission in a car like this would help because the driver could select, for example, second or third gear and get 4000 or 4500 RPMs at 60mph and this would be good for battery life and EV range. Do drivers of such EVs do any gear shifting? Seems like the electric motor would destroy itself as soon as the driveline load was removed by the clutch.

I'm not sure why it would destroy itself. You still have a controller, so when you go to shift you let off the 'gas' pedal. A lot of guys just opt to get rid of the clutch as it seems this guy has also done. Thats not really my cup of tea, but its quite common.

These motors are kinda backwards from a gas engine in how you operate them efficiently. You want higher rpms and low amps (amps is kinda equal to torque) and they're happier in general.

Taking what Daox said a step farther... In a car like this around town you might cruise in second gear but shift to third for max acceleration. That is because with only 72 volts there might not be enough voltage to supply the max amps at higher RPM. Seems backward at first.

I love the concept and the engine bay. With that small of a motor it seems like you could stack lithium ion batteries in the engine bay