# curtis 1221c sudden death? HELP



## dtbaker (Jan 5, 2008)

driving today, accellerating from a light.... car lurched, bucked, died. I have about 25k electric miles on the controller. about 10k were put on with a 96v nominal lead-acid pack, and the remainder with a 120v nominal LiFePO4 pack. Absolutely no electrical faults the whole time, except for a short-lived chennic dc-dc, until now.

instrumentation shows pack voltage ok (main inline fuses ok), main contactor is powered, DC-DC has power....

I didn't have a multimeter with me, so I don't know if the fault lies within the controller or motor. I just got home, am packing up a few tools to go take a quick look before dark. If anybody has ideas on what to check, please post!


.... just got back from quick check w multimeter.
I have HV going into the controller, KSI power is good, no voltage showing between batt+ and motor m- terminal OUT of controller with accel pot box manually pulled mid-throttle. so..... must be controller?

questions I have are:

- does the Curtis 1221c have any internal fuses? (no access covers I can see?!)

- how can I be SURE if fault is in controller, or motor itself?


....i'll check back later tonite, hoping someone has a brilliant idea.


----------



## dcb (Dec 5, 2009)

did you check the throttle voltage signal to the controller?


----------



## dragonsgate (May 19, 2012)

I have had my cutis opened up a couple of times and do not remember seeing any fuses.


----------



## nimblemotors (Oct 1, 2010)

curtis has no serviceable parts inside, i.e. fuse.

Disconnect the controller and power the motor directly at 12-24v and see if it spins.


----------



## dtbaker (Jan 5, 2008)

dcb said:


> did you check the throttle voltage signal to the controller?



didn't.... hard to imagine the pot box failing mid-acceleration, but I guess it's possible. I will check w ohm-meter tomorrow....


----------



## dtbaker (Jan 5, 2008)

nimblemotors said:


> curtis has no serviceable parts inside, i.e. fuse.
> 
> Disconnect the controller and power the motor directly at 12-24v and see if it spins.



not a bad idea... I can jumper from my dc-dc 12v output since that is still working. It shouldn't draw too much load to spin in neutral, right? that would tell me the motor is ok.


----------



## dcb (Dec 5, 2009)

running your motor off your dc-dc converter DOES sound like a bad idea.


----------



## nimblemotors (Oct 1, 2010)

dtbaker said:


> not a bad idea... I can jumper from my dc-dc 12v output since that is still working. It shouldn't draw too much load to spin in neutral, right? that would tell me the motor is ok.


I wouldn't use the dc-dc, the inductance in the motor might damage it.
Can you tap 12v off the battery pack? I'd just use a 12v car battery.

It is probably the controller, so might just test it on another motor, like a starter motor or just a big coil of wire (must have inductance) and see if it works by checking the current flow through the coil of wire with an ammeter.


----------



## dtbaker (Jan 5, 2008)

nimblemotors said:


> I wouldn't use the dc-dc, the inductance in the motor might damage it.
> Can you tap 12v off the battery pack? I'd just use a 12v car battery.
> 
> It is probably the controller, so might just test it on another motor, like a starter motor or just a big coil of wire (must have inductance) and see if it works by checking the current flow through the coil of wire with an ammeter.



I was looking for 'parking lot diagnostics'.... after I get it home I can use an external 12v battery rather than the dc-dc.


----------



## mk4gti (May 6, 2011)

There is a troubleshooting chart/matrix in the manual.


----------



## dtbaker (Jan 5, 2008)

pulled the controller.... tipping it around, there is something loose inside, sounds like something in there blew up. It's pretty well sealed up, I can't see how to open it up very easily, so I'll just toss it.

I happen to have an old used one I picked up for a cheap spare, but no idea how long it will last. I may have to do a major upgrade to a nice controller.

I think I will start a thread to see how long other people have had Curtis 1221 last.....


----------



## nimblemotors (Oct 1, 2010)

Hope you didn't trash it, I'll take it off your hands.



dtbaker said:


> pulled the controller.... tipping it around, there is something loose inside, sounds like something in there blew up. It's pretty well sealed up, I can't see how to open it up very easily, so I'll just toss it.
> 
> I happen to have an old used one I picked up for a cheap spare, but no idea how long it will last. I may have to do a major upgrade to a nice controller.
> 
> I think I will start a thread to see how long other people have had Curtis 1221 last.....


----------



## Dougnutz (Aug 22, 2011)

I missed this thread somehow when searching. (should have used the google option) Anyway I'm in a similar boat. Fortunately my breakdown was in the driveway. I didn't hear any thing unusual but I'm fairly sure I am on the lookout for a new controller.


----------



## dtbaker (Jan 5, 2008)

Dougnutz said:


> I missed this thread somehow when searching. (should have used the google option) Anyway I'm in a similar boat. Fortunately my breakdown was in the driveway. I didn't hear any thing unusual but I'm fairly sure I am on the lookout for a new controller.



one of the guys here earlier in the thread may be able to 'repair/upgrade'. I am going to send him my carcass, but I'm planning on replacing with a zilla or solliton this summer. I was able to locate a used curtis for fairly cheap, but don't know how long it'll last .


----------



## Dougnutz (Aug 22, 2011)

Ya, I'm leaning toward a zilla 1k myself. I would really like to go big with the 2k but I imagine a 1k is more than suitable for my needs. And would be a huge improvement over the Curtis.


----------



## dtbaker (Jan 5, 2008)

Dougnutz said:


> Ya, I'm leaning toward a zilla 1k myself. I would really like to go big with the 2k but I imagine a 1k is more than suitable for my needs. And would be a huge improvement over the Curtis.



the 1k would be more than enough..... you'd have to be careful and limit output amps so as not to break the transmission or burn up the clutchplate.


----------



## Dougnutz (Aug 22, 2011)

More than enough?

So my conversion is a truck. 3700lbs of heavy, slow, work horse. I consider the Curtis controller to be somewhat equivalent to a small 4 cylinder engine. Maybe mine has been on the way out for a while but it has never impressed me with power. It's rated at 500 Amps peak and the 1k is double that, but I don't feel like I will be in danger of snapping any drivetrain parts by doubling the power the Curtis provides.

I hope I am wrong, I would love to have to detune the controller. Is there some other aspect of the controller other than the peak amps that make the Zilla much more powerful?

If so I might look back on this break down as a blessing.


----------



## nimblemotors (Oct 1, 2010)

As dtbaker indicated (hey when you gonna send that unit..) I can update the curtis to 1000+ amps, there is a thread here on it (A 1231 and a 1204 to 600 amps too!) I replace the entire logic board with a micro controller and current sensor, so the issues others had with upgrading them don't apply. Basically a new controller using the metal.

A 1221c in a big truck is very weak. The 1231c in my fiero was weak too, the biggest issue is they get hot quickly, and then forget 500 amps, more like 200 amps, and then acceleration sucks.


----------



## dtbaker (Jan 5, 2008)

Dougnutz said:


> More than enough?


I thought you had a Swift/Metro.  They are designed for 85hp

...the ability to put 1000amps into a Warp9 is probably about right for some very decent performance with a truck. That combo puts out same torque as the average small block v8 if you are at 144v-156v.





Dougnutz said:


> I hope I am wrong, I would love to have to detune the controller. Is there some other aspect of the controller other than the peak amps that make the Zilla much more powerful?
> 
> If so I might look back on this break down as a blessing.


both Zilla and Soliton have WAY more control over what you can limit, low voltage 'limp home' to prevent toasting batteries, and way better (fluid) cooling plate w ports built in.


----------



## domosher (Jul 10, 2011)

if you shake a 1221 or 1231 and it rattles it is blown up. I can repair it for you or upgrade it to 1200 or 1300 amps respectively at about 1/2 the cost of a new one. my email address is [email protected]


----------

