# curtis 1231c failure?



## ragee (May 25, 2008)

I finally got my transmission back from shop getting rebuilt. Was out for 3 months so I painted and did some body work while it was tore down. Was putting it all back together and went to test it and nothing. 

I started trouble shooting it and found 0 volts from the load side of my controller. I am getting 152 volts to the B+ and B- when both contactors are pulled in. Does this mean that the controller has failed?

Has anyone else had this problem.

Any help is appreciated

Thanks,
R Agee


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## ngrimm (Oct 19, 2007)

Sounds like you're not getting a good connection between the B- on the controller and the negative battery terminal. Also what are you using as a ground reference for measuring the voltage?


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## TheSGC (Nov 15, 2007)

It sounds like your Keyswitch is not plugged in or your high pedal disable is kicking in.


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## ragee (May 25, 2008)

ngrimm said:


> Sounds like you're not getting a good connection between the B- on the controller and the negative battery terminal. Also what are you using as a ground reference for measuring the voltage?


No getting good solid connections on negative side all the way to controller. Double checked those already. My pack voltage doesnt go to ground it is a closed loop so I am checking voltage right at the controller.


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## ragee (May 25, 2008)

TheSGC said:


> It sounds like your Keyswitch is not plugged in or your high pedal disable is kicking in.


I have bypassed the key switch and the back wheels are jacked up and on stands. I have the transmission in 1st gear so I am moving the potbox by hand to engage the secondary contactor. I start it in the off or 0 ohm position and then move it to the on position and up to half throttle while my voltmeter is connected to B+ and M- on the controller. I get a 0 volt reading.


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## ngrimm (Oct 19, 2007)

Sorry, I thought you meant you were measuring 156v at both the B+ and B- terminals whereas you are actually measuring between the two. I think TheSG is on the right track. Are you getting a positive voltage on the KSI pin and do you get a voltage swing between the throttle inputs when you depress the pedal?


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## ragee (May 25, 2008)

ngrimm said:


> Sorry, I thought you meant you were measuring 156v at both the B+ and B- terminals whereas you are actually measuring between the two. I think TheSG is on the right track. Are you getting a positive voltage on the KSI pin and do you get a voltage swing between the throttle inputs when you depress the pedal?


Not sure on the KSI and the throttle inputs. I will check that in the morning. 

And thanks for the help.


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## rfengineers (Jun 2, 2008)

Another possibility is a loose connection somewhere in the series battery path. It will measure full voltage under no load but when you draw even a little bit of current you get enough voltage drop at the bad connection to cause the controller to go into low-voltage shutdown. It happened to me and cost me shipping both ways to send my "bad" controller back for repair.


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## ragee (May 25, 2008)

rfengineers said:


> Another possibility is a loose connection somewhere in the series battery path. It will measure full voltage under no load but when you draw even a little bit of current you get enough voltage drop at the bad connection to cause the controller to go into low-voltage shutdown. It happened to me and cost me shipping both ways to send my "bad" controller back for repair.


Hmmm..... bad connections? Good point as I was working on it all day putting it back together I might of missed tightening a lug or two. I will certainly check that first thing in morning before I call Bob at EV-America. 

It is a long story but I think I might have blown it before I tore it down. I thought it was something mechanical in the transmission when it originally quit on me by blowing the main power fuse. After rebuilding the transmission and almost sending my motor back to manufacturer before I realized to test it with a larger amp battery I think the controller might have been my original problem. I started back to work one day and I forgot something so I shut it off and ran back to house to get whatever it was and I jumped in and took off real quick and that is when I think I blew it up. Just a hunch because I have since read that you shouldnt do that. So yea I could have screwed up somewhere along the line. LOL go figure.

Thanks for suggestion,
R Agee


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## ragee (May 25, 2008)

rfengineers said:


> Another possibility is a loose connection somewhere in the series battery path. It will measure full voltage under no load but when you draw even a little bit of current you get enough voltage drop at the bad connection to cause the controller to go into low-voltage shutdown. It happened to me and cost me shipping both ways to send my "bad" controller back for repair.


I rechecked my connections and they were tight. I hooked up a 120v electric heater, very briefly, to the B+ and B- poles on the controller and it started heating so I am getting 152v at high amps at the controller connections. Still nothing out of B+ to M- poles or nothing through the controller. :~(


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## rfengineers (Jun 2, 2008)

ragee said:


> I rechecked my connections and they were tight. I hooked up a 120v electric heater, very briefly, to the B+ and B- poles on the controller and it started heating so I am getting 152v at high amps at the controller connections. Still nothing out of B+ to M- poles or nothing through the controller. :~(


Well, at least you've eliminated my big miss-steak.
Are you applying pack voltage to the KSI terminal? Try a clip-lead jumper direct from B+ to KSI.


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## ragee (May 25, 2008)

rfengineers said:


> Well, at least you've eliminated my big miss-steak.
> Are you applying pack voltage to the KSI terminal? Try a clip-lead jumper direct from B+ to KSI.


I will try that next I hook a lead to B+ and where do I hook lead to KSI? what does this do? Is it jumping around controller or am I checking for volts on my voltmeter?


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## rfengineers (Jun 2, 2008)

ragee said:


> I will try that next I hook a lead to B+ and where do I hook lead to KSI? what does this do? Is it jumping around controller or am I checking for volts on my voltmeter?


There are three low current connections on the controller. Two connect to the throttle pot. The third is the KSI (Key Switch Input). Look at figure 8 on page 9 of the Curtis manual. You will see that KSI is normally connected to the B+ terminal through the KSI relay. If you jumper KSI directly to B+ (just temporarily for testing purposes), it will eliminate the KSI relay as a possible source of your problem.
Figure A-1 on page A-1 of the manual shows how the KSI switches the internal power on and off.


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## ragee (May 25, 2008)

rfengineers said:


> There are three low current connections on the controller. Two connect to the throttle pot. The third is the KSI (Key Switch Input). Look at figure 8 on page 9 of the Curtis manual. You will see that KSI is normally connected to the B+ terminal through the KSI relay. If you jumper KSI directly to B+ (just temporarily for testing purposes), it will eliminate the KSI relay as a possible source of your problem.
> Figure A-1 on page A-1 of the manual shows how the KSI switches the internal power on and off.


Ok, did that and still nothing.

By the way thanks for helping,

R Agee


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## rfengineers (Jun 2, 2008)

ragee said:


> Ok, did that and still nothing.
> 
> By the way thanks for helping,
> 
> R Agee


Wow, this is a tough one.

If you have:
1. Pack voltage between B+ and B-,
2. Pack voltage between KSI and B-,
3. Zero to 5000 Ohms applied to the throttle input, (more than 7000 Ohms will cause controller shutdown),

Then you should get a DC voltage reading between B+ and M- when the throttle pot exceeds 300 Ohms.

Try disconnecting the B+ M- leads from the controller and connect them (briefly) to a single 12 Volt battery with jumper cables. The motor should turn (be very careful, if the motor is miswired or shorted you could damage the battery or cause an explosion). If it does not turn, then there is something wrong with the motor or wiring.


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## rfengineers (Jun 2, 2008)

Pages 28 through 34 of the Curtis manual has a fairly detailed procedure for troubleshooting your controller. We have already discussed most of the steps listed there, but perhaps if you read through it you might see something we missed.


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## ragee (May 25, 2008)

rfengineers said:


> Wow, this is a tough one.
> 
> If you have:
> 1. Pack voltage between B+ and B-,
> ...


No I dont have pack voltage between ksi and B-


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## rfengineers (Jun 2, 2008)

ragee said:


> No I dont have pack voltage between ksi and B-


That means the controller is not turned on.

Do you have a copy of the manual? you can download it from 

http://curtisinst.com/index.cfm?fuseaction=cProducts.DownloadPDF&file=1209.pdf


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## ngrimm (Oct 19, 2007)

ragee said:


> No I dont have pack voltage between ksi and B-


I think you're getting close.


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## ragee (May 25, 2008)

rfengineers said:


> That means the controller is not turned on.
> 
> Do you have a copy of the manual? you can download it from
> 
> http://curtisinst.com/index.cfm?fuseaction=cProducts.DownloadPDF&file=1209.pdf


Yes I have it and am going to spend the day going through every component and the controller. Just got off the phone with Bob from EV-America and he is suggesting the same thing before I send it back to him. So that is where I'm at thanks for advice.

R Agee


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## ragee (May 25, 2008)

ngrimm said:


> I think you're getting close.


LOL,
I dont see it that way. This stuff is mind boggling for an electrical misfit like myself. We'll see how it goes today.

R Agee


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## F16bmathis (Jun 6, 2008)

Hey,

I stupidly connected the 144V "on" signal to the 1231C to one of the pot connectors that are all next to each other and are the same size and shape. So, now that excuses are out of the way...

Does anyone know, is there any way besides boiling water, to open the case, and can I get parts? Pretty sure I fried the 15V card with the 144V.

Thanks!


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## rfengineers (Jun 2, 2008)

F16bmathis said:


> Hey,
> I stupidly connected the 144V "on" signal to the 1231C to one of the pot connectors that are all next to each other and are the same size and shape. So, now that excuses are out of the way...
> Does anyone know, is there any way besides boiling water, to open the case, and can I get parts? Pretty sure I fried the 15V card with the 144V.
> Thanks!


I haven't figured out how to break into one yet.

Assuming that the 1231C input circuit is similar or identical to the 1221 (see schematic clip below) there is little protection against such an error. Ouch.


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## F16bmathis (Jun 6, 2008)

There are ads saying you can open the with boiling water, and another method that requires less than 50 degrees C. (122F). I'm just not sure if after opening it, that it'll do any good, or that the repair guy will charge less than the $635.00, or that I'll be able to find parts. But for $600, I might just order a new one... Still waiting on my Zilla!


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## ragee (May 25, 2008)

I went through the manual for the controller and it failed the test so now its out and gonna ship it back tomorrow. Basically it past all of them exept the last one

Check voltage output while depressing pedal (B+ to M-).
Voltage should be zero with pedal UP, and full battery voltage with pedal DOWN.

if NO

Controller is defective.

So now it is back to the shop and wait again. 

But I did accomplish one thing to add to my electrical experience, I fried my DC to DC converter by wiring it back in wrong. Crap. Just a fine day all in all.

R Agee


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## F16bmathis (Jun 6, 2008)

Opened the Curtis 1231C. It was easy, remove the two rubber covers on each of the 8 holes, remove the mounting screws and plastic inserts. I used a kerosene heater I use to heat the garage to warm the top of the controller. I had a coat hangar tied through two of the lugs, B+ and B-, heated the top, turning constantly, and used a rasor knife to go along the edge of the case where the black rubber seal is, and then heated again, and pulled it right out! 

I can see a burned spot on the throttle card that should be my problem, plus I have a friend who says he can fix it now that its open...


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## F16bmathis (Jun 6, 2008)

Also, I'm not sure that I needed to heat it. To open the Curtis 1231C, after the bolts are out and the rubber seal has been cut with a razor, I beiliev it will just pull out. No boiling water needed!


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## F16bmathis (Jun 6, 2008)

Yup, its obvious I connected the 144V to the throttle input. You can see the burnt circuit card and trace it from the throttle input for a way onto the board. I'm not sure if I can pull the board without messing up the temp sensor and there's two connectors I'm not sure how to disconnect. No luck in finding parts either...


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## the gas wizard (Apr 19, 2008)

i'm having the exact same drama! i just hooked all the parts up and nothing! not a peep! is the top terminal meant to have power the entire time the unit is running or only when the throttle is at rest? i have pack voltage at b+ b- i have 2.7 volts from the pot box at rest and 6.99volts at WOT....still nothing! any ideas????? please help me?


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## ragee (May 25, 2008)

the gas wizard said:


> i'm having the exact same drama! i just hooked all the parts up and nothing! not a peep! is the top terminal meant to have power the entire time the unit is running or only when the throttle is at rest? i have pack voltage at b+ b- i have 2.7 volts from the pot box at rest and 6.99volts at WOT....still nothing! any ideas????? please help me?


I sent mine back to Bob with EV-America and he bench tested it and it failed. He sent it back to Curtis and I am waiting to find out if it was me or a defect. It ran for about a month just fine before it failed so I think I had it all hooked up correct. I will post what I find out from Curtis and if it was my doing I would like to find out how to avoid this in future.

R Agee


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## the gas wizard (Apr 19, 2008)

thanks for the fast reply! the good news is i worked it out with mine last night after posting this in a panic! it was a faulty ksi solid state relay. i replaced it and it works awesome now! sorry about your one though


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## ragee (May 25, 2008)

Thats great, a ksi fuse is much cheaper than a controller. But the good news is that maybe mine is just a bad controller or even a screw up of mine. In my opinion that is much better than a whole bunch of controllers having the same problem. We dont need any more controllers having a mass melt down such as in the logisystem or kelly controllers. 

R Agee


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## the gas wizard (Apr 19, 2008)

not a truer word was spoken by a wiser man! good luck!


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## F16bmathis (Jun 6, 2008)

YES, the "top" terminal being the one on the far end closest to the edge of the controller is meant to have voltage on it when you want it to run.

Mine is set up so when pressing the throttle, the throttle sw sends 12v to a relay that lets 144V go to that terminal.

My first controller, I hooked the throttle pot wire to that terminal and the 144V to a pot terminal, blew the circuitry and still waiting for repairs (two weeks usually). Other than nothing working, I couldn't tell I had blown it till I opened it up and saw all the burnt circuitry.


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## ragee (May 25, 2008)

I am still not sure what the reason is that my controller is toast. Still waiting for response from Curtis whither or not is my fault or there's. Lemme see ummm........... probably mine.

This Friday it will be a month so I hope this week maybe someone will make a determination. 

Sounds like a relay in front of it wouldnt be a bad idea though.

R Agee


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## F16bmathis (Jun 6, 2008)

Anything to make it look different or something... I'm sure I'm not the first or the last to connect the 144V to the POT connection. 

At least unlike Kelly, a 500 amp Curtis CAN get you going 70+ mph! I hit 67 in the S10 in 20 degree weather the other day. Finished installing battery heaters (water pipe warmer wire placed in foam cut with a router to form a heater "blanket" under all the batteries. Plug it in at night, 80 degrees by morning, stays warm all day unplugged! I should have better range and speed now...


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## ragee (May 25, 2008)

Yea,
thats why I'm inclined to believe it was something I did, however it was running fine when it happened, but Curtis seems to be reliable from everything I have read here. I had no trouble reaching 60 to 70 mph with it.


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## ragee (May 25, 2008)

I finally got word from Curtis. They said it was nothing I did and authorized EV America to send me a new one. I should be getting it this coming Wednesday which means my rig will be running again by next weekend. WooHoo......... 

R Agee


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