Paul's how NOT to convert a Metro

[MPaulHolmes]

Hello! Now I'm using four 50 Ohm resistors in parallel (40 watts again), for a resistance of 12.5 Ohms. It seems to work fine. I didn't realize that Curtis used such a large resistor. Mine is set up so that it would get hot if it was precharging for a long time, but it only takes like 1 or 2 seconds, so it doesn't matter.

The reason I replaced the 2.5 Ohm 40 watt resistor was because I accidentally put the capacitors in backwards on an old controller, so the circuit looked like 72v+ ----- 2.5Ohm ----- Ground. For a long time! It never precharged! It started smoking. It was pretty much awesome, but the resistor was burned up.

[vpoppv]

The contactor came in. So I wired it all up today!!!! I was sooooo nervous!! I had thick rubber gloves on the whole time!. I connected all the small stuff: 12v(switched) to contactor, 12v (switched) to Curtis controller input one. Potbox (stock Geo TPS, didn't use toilet one) to input 2 and 3. Connected a lightbulb as pre-charge resistor (I have the one Curtis recommends on order), connected a "temporary" safety switch (battery disconnect), wired up the batteries. Checked and double checked. Then went back and checked again with Curtis diagram in my hands. Then sat down and had sauerkraut, sausage, and twisty noodles leftover from last night. I told the girls (8 and 5) how it's SUPPOSED to happen: I will flip the safety switch and the light bulb will turn on. Then, I wait until the light bulb goes out meaning the pre-charge is over. Then I turn the key and the contactor will close and the controller will turn on. Then I push on the accelerator and the motor will spin!
I quickly ate lunch and went out to the car! Flipped the switch: hoorah! the light bulb shines...and slowly fades to nothing in a few seconds. Then, I turn the key...fingers crossed......Hourrah! the contactor closes!!!! My heart is POUNDING!!!! So then I sllloowwwly open the throttle andddddd.....nothing. Nada. Diddly squat. Zip. Zero. Zilch. That was about 2 and half hours ago. Tried the toilet TPS, tried running 60v, tried running 48v. No go. In an ironic twist of fate, I just won an eBay auction (5 minutes ago)for "Build Your Own Electric Vehicle" by Bob Brant.....

[TheSGC]

I was looking through the Curis 1209b manual and the KSI should have full Pack Voltage, so that could be your problem.

[vpoppv]

Originally Posted by TheSGC

I was looking through the Curis 1209b manual and the KSI should have full Pack Voltage, so that could be your problem.

I suppose it couldn't hurt to try, although I really liked the fact that the turning on of the controller was independent of the contactor closing. Heck, I'd pi** on a spark plug if I thought it would work....

[vpoppv]

David,
The more I think about it, the more I think you're right! There is no accessory battery negative going to the Curtis anywhere! How does it "know" it's getting 12v??? I'm sending 12v to input 1, but there is no "ground" going to the Curtis anywhere! It's not sensing the voltage! Could it be???

[TheSGC]

Originally Posted by vpoppv

David,
The more I think about it, the more I think you're right! There is no accessory battery negative going to the Curtis anywhere! How does it "know" it's getting 12v??? I'm sending 12v to input 1, but there is no "ground" going to the Curtis anywhere! It's not sensing the voltage! Could it be???

YES YES YES!!! THAT WOULD DO IT!

So add a Pack voltage +72 to that pin and things should be happy!

You can use a 12 volt Automotive relay to activate the 72 volts to the Pin1 if you want, that's what I used when I had 60 volt contactor coils before I got my hands on the bigger SW200 ones. I had a relay run off my ignition switch to turn on the contactors, then turn on the controller.

[vpoppv]

Originally Posted by TheSGC

YES YES YES!!! THAT WOULD DO IT!

So add a Pack voltage +72 to that pin and things should be happy!

You can use a 12 volt Automotive relay to activate the 72 volts to the Pin1 if you want, that's what I used when I had 60 volt contactor coils before I got my hands on the bigger SW200 ones. I had a relay run off my ignition switch to turn on the contactors, then turn on the controller.

Ok, I'm going to ask you further about the relay thing because that has me totally lost, but that's for later! Right now, new problem:
I made a wire to go from the contactor contact to input 1. Buuuutttt, when I clicked on the safety switch, the pre-charge resistor (light bulb) went on, but never went off!!!! So I just shut it off without trying. I want to know why the bulb isn't going out like before????
So close.....

[vpoppv]

I have a crudely drawn picture that I am putting up just because it took me a lot of effort and I posted it in another forum. There's five minutes I'll never see again...

[TheSGC]

OK, put a switch on the connection that goes from +72 to Pin 1. The controller needs to precharge before Pin1 gets turned on, or the controller starts to function and the light bulb will stay on cause its trying to draw power through the bulb, which is too little power to actually do anything except charge the controller up.

Once the bulb goes out, the controller is now precharged and you can activate Pin1 and your contactor and it should be good.

[vpoppv]

Originally Posted by TheSGC

OK, put a switch on the connection that goes from +72 to Pin 1. The controller needs to precharge before Pin1 gets turned on, or the controller starts to function and the light bulb will stay on cause its trying to draw power through the bulb, which is too little power to actually do anything except charge the controller up.

Once the bulb goes out, the controller is now precharged and you can activate Pin1 and your contactor and it should be good.

Once again, you were right!!! You have chosen the right field to pursue in college!!

So, I had to adjust the TPS a little, but...I think I have an EV