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Old 04-07-2009, 06:23 PM   #797 (permalink)
EV test pilot
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Join Date: Jan 2008
Location: Oconomowoc, WI, USA
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I know that the Curtis controllers use a 0-5kohm input, and that if you go HIGHER than 5K, it just stops working all together.

It actually doesn't start doing anything at all until up a bit from zero and maxes out somewhere around 4700 ohms.

I think this is both for safety and to account for potentiometers which are slightly out of spec.

I suppose I could always put the car in neutral, turn it on, then pull out the throttle wire and see if anything happens?

The controller spins the motor! Yea!

This controller "feels" different than the Curtis.

The Curtis has a really nice smooth slow start when you accelerate very gently. The open source controller has a bit of a shutter if you try to do a really slow start.

I believe that's the current-limiting feature?
Makes me think that a switch to turn that on or off might be pretty cool.
I guess it just depends how much you like doing things manually instead of having a computer do it for you. In a car, I like manual.

Photos for you!

Here is the open source controller next to the Curtis controller. You can see that the open source is somewhat larger. It has a lot of space inside the box and it has a heat sink on the bottom as well.

I removed the Curtis, and made some room for the open source.

Here, you can see the controller, with the M- cable on the left and the B+ and B- cables on the right. Do NOT stick your hand between the B+ and B- cable when forgetting to disconnect the main battery shut-off! Ouch! 144V bites harder than 72V!

The 12v wires and throttle wires use insulated spade connectors. I also have insulated spade connections on my PB-6 throttle, but they are exactly slightly different enough that I had to make some short custom jumpers to plug in the throttle and 12V power.

In case of emergency....Pull this rope.
I screwed down one half of the battery disconnect to the back seat battery box lid, and tied a rope to the other half. Give it a yank! No more power!

I now have a 144V battery pack, but only a 72v charger! One way to solve this is to charge half the total pack at a time. I got another 50 amp Anderson plug, which matches what's built into the charger. I wired that plug to one half of the battery pack, and the original connection to the other.
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Last edited by bennelson; 04-07-2009 at 06:41 PM.. Reason: added photos
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