# Curtis 1231C Upgrade to 144V 1200 Amps?



## Bowser330 (Jun 15, 2008)

tj4fa said:


> From a newsletter I received from Electric Vehicles of America:
> 
> You can sign up for their newsletter at their website here:
> 
> ...


question is how much....$$$

They do have a pretty reputable name in the DIY community...so it would sell if they kept the price down to sub 2K$.... but if they go much over that...they will be competing with the Soliton-1 and the Zilla-1K....some a pretty power potent pair...


----------



## EVComponents (Apr 20, 2009)

I am not meaning to jump on someones thread, so if this is out of line, I apologize. 

I just wanted to mention that the Zilla1K-LV (low voltage) can regulate up to 1000 Amps of motor current and run on battery packs of 72 to 156 volts nominal.

It is also upgradable to the High Voltage (72 to 300 volts nominal) or even Extra High Voltage (72 to 348 volts nominal). The max cutoff is 429 volts.

The point I am trying to make is this. Your low voltage Zilla1K can grow with you as you improve your EV or if you decided to build something else entirely that is higher voltage.


----------



## tj4fa (May 25, 2008)

EVComponents said:


> I am not meaning to jump on someones thread, so if this is out of line, I apologize.
> 
> I just wanted to mention that the Zilla1K-LV (low voltage) can regulate up to 1000 Amps of motor current and run on battery packs of 72 to 156 volts nominal.
> 
> ...


Nope, not out of line as far as I'm concerned.

I just posted that because I felt it might be a good thing for people who already have a 1231C Curtis controller (like me) and for a bit more money (yet to be determined) could easily upgrade my existing controller to a higher performance unit.

From what I've read and seen, the Zilla's are absolutely great stuff, but for myself when first starting out last year, the Zillas weren't readily available and weren't within my cost range. I also didn't hear anything bad concerning Curtis controllers.

I guess as component technology and DIY EV demand develops, more companies and individuals are coming up with a wider choice of options and improved equipment. For Joe the Ev'er, this equipment variety and competition can be a good thing. 

If I were an initial buyer for a controller right now, it would still come down to how much performance, flexibility, and dependability that I could afford. 

If the Curtis controller upgrade cost turns out to be out of my price range, well then that will be a consideration for another day, but for me there will at least exist another option...


----------



## Mo_Bandy (Aug 25, 2009)

This is awesome news... I have been debating when I start deciding to put more power to my Vette at least now I have an upgrade path...

Thanks for Sharing!

MO


----------



## ElectriCar (Jun 15, 2008)

I sent my controller to EVA and David evaluated it. They said the 1200A upgrade was $1000 and included another upgrade which is called a "speed-up mod". 

The speed-up mod is $200 if gotten alone and turns the transistors on and off faster. Not sure of the benefit of this other than possibly reducing heat generation.


----------



## Qer (May 7, 2008)

$1200 for beefing up an old, analogue controller?!? Shees. Syncromotive isn't that much more money and then you can sell the old Curtis on Ebay instead. I'd at least think it over twice before starting to throw money on an almost ancient design like the Curtis.

Not that I think Curtis is bad or so, the 1231C is ok for the price but it's not really a design I'd trust with this kind of power when you have the potential to burn up the motor or blow batteries to Kingdom Come...


----------



## Bowser330 (Jun 15, 2008)

ElectriCar said:


> I sent my controller to EVA and David evaluated it. They said the 1200A upgrade was $1000 and included another upgrade which is called a "speed-up mod".
> 
> The speed-up mod is $200 if gotten alone and turns the transistors on and off faster. Not sure of the benefit of this other than possibly reducing heat generation.


Are you going to go for the upgrade?

If so, please do report back with the results.

From what I have gathered about controllers in the DIY EV Community the Curtis 144V 500A is the most reliable controller out there...I just hope the upgrade doesn't threaten that reputation...


----------



## Mo_Bandy (Aug 25, 2009)

ElectriCar said:


> I sent my controller to EVA and David evaluated it. They said the 1200A upgrade was $1000 and included another upgrade which is called a "speed-up mod".
> 
> The speed-up mod is $200 if gotten alone and turns the transistors on and off faster. Not sure of the benefit of this other than possibly reducing heat generation.


 
Thank you for the update!

MO


----------



## ElectriCar (Jun 15, 2008)

No it's not $1200 for the two upgrades. It's $200 for the speed upgrade or $1000 for BOTH upgrades. 

Granted I'd love to have an AC system if I had my druthers... However I just want reliability and efficiency. Personally not building anything needing this much juice just relaying info offered to me when they tested my unit, which came back ok. 

My controller problem was with the heat sink from EVA, which is not adequate. It's only maybe 1/8" thick and flimsy. Wasn't making good contact with the controller base thus not transferring heat from the unit well causing my unit to overheat and cutback in 80F+ temps. 

David said it should probably be 1/4-3/8" minimum thickness and of a more rigid type aluminum versus what EVA is shipping.


----------



## tj4fa (May 25, 2008)

ElectriCar said:


> No it's not $1200 for the two upgrades. It's $200 for the speed upgrade or $1000 for BOTH upgrades.
> 
> Granted I'd love to have an AC system if I had my druthers... However I just want reliability and efficiency. Personally not building anything needing this much juice just relaying info offered to me when they tested my unit, which came back ok.
> 
> ...


With your controller, did you smear heat sink grease between the controller and the 1/8" heat sink base?

Did you install a 12V fan (or fans) under the controller/heat sink to help keep the controller cool?

Outside temperature is a consideration, but the controller will heat up more from the power its running at -ie; pulling a lot of amps going up hills or running at high speeds for prolonged periods.

I noticed the top of my controller was heating up to around 150*F when I checked it with an IR temperature sensor after running it a while ago. I have a 3" air hose from a dust collection system and will hook it up in front of the controller fan and will ram air into it to help cool the controller if needed. 

A friend was going into "limp mode" during the summer last year and ducted air from the front of the vehicle into the motor bay to help cool the controller. It worked well.


----------



## ElectriCar (Jun 15, 2008)

tj4fa said:


> With your controller, did you smear heat sink grease between the controller and the 1/8" heat sink base?
> 
> Did you install a 12V fan (or fans) under the controller/heat sink to help keep the controller cool?
> 
> ...


Yea greased it and used a fan. Also added a second and larger fan after it started giving problems, which helped a bit. What I found when I removed it was that the rubber screw covers on the bottom were protruding out some and warping the plate, thus the comment about it being too thin and not a rigid material. I'm putting a new thicker sink on it made from a more rigid aluminum if I can find it. That should do the trick. 

Another mod they recommended as I can only pull an average amperage from a dead stop of around 90 amps off the pack, is to take a 4" PVC conduit or pipe and wrap 10-15 turns of 4/0 cable around it. That is to be installed in place of the motor jumper wire. Said this will prevent the drive current from spiking or something like that causing the drive to limit current output and will give me a higher average amp draw off the pack, thus giving me more power and accelleration. I remember from school that a coil like that will store energy sort of like a capacitor as the input current increases. When the drive pulse turns off momemtarily, that energy will be forced into the motor.


----------



## tj4fa (May 25, 2008)

ElectriCar said:


> Yea greased it and used a fan. Also added a second and larger fan after it started giving problems, which helped a bit. What I found when I removed it was that the rubber screw covers on the bottom were protruding out some and warping the plate, thus the comment about it being too thin and not a rigid material. I'm putting a new thicker sink on it made from a more rigid aluminum if I can find it. That should do the trick.
> 
> Another mod they recommended as I can only pull an average amperage from a dead stop of around 90 amps off the pack, is to take a 4" PVC conduit or pipe and wrap 10-15 turns of 4/0 cable around it. That is to be installed in place of the motor jumper wire. Said this will prevent the drive current from spiking or something like that causing the drive to limit current output and will give me a higher average amp draw off the pack, thus giving me more power and accelleration. I remember from school that a coil like that will store energy sort of like a capacitor as the input current increases. When the drive pulse turns off momemtarily, that energy will be forced into the motor.


I think EVA used to send a thicker HSink plate and then went to the 1/8" plate. 

Since heat rises, I think it might be good idea to have a fan blowing on the upper part of the controller if space permits (but it doesn't in my application). I do have some insulation in my (black) hood above it that might help keep the heat from the sun off of it.

Wow only 90 Amps from a dead start? I read my amps with the amp shunt installed before the motor and I get WAAAYYY more than that.

I remember Bob from EVA saying something about this coil and thought it was to correct some controller surging - maybe these spikes your mentioning is the same thing. I get a little surging about 35 mph but goes away when I go faster. I might try the coil thing.


----------



## ElectriCar (Jun 15, 2008)

tj4fa said:


> I think EVA used to send a thicker HSink plate and then went to the 1/8" plate.
> 
> Since heat rises, I think it might be good idea to have a fan blowing on the upper part of the controller if space permits (but it doesn't in my application). I do have some insulation in my (black) hood above it that might help keep the heat from the sun off of it.
> 
> ...


David said I built my system too well. I used parallel 1/0 instead of a single 2/0 cable. This was to lower the voltage drop across the wires in the battery side resulting in more of the pack voltage applied to the controller. More voltage on the controller = more current to the motor. He said the coil would prevent such a large surge as coils oppose current changes in a circuit, effectively limiting the surge current out of the drive and preventing it from going into over current and shutting down prematurely.

As far as the pack current goes, as it would only draw 90 amps, the motor circuit would pull close to or more than 500 amps. The coil will reduce that surge and allow the control to stay on longer.


----------



## tj4fa (May 25, 2008)

ElectriCar said:


> David said I built my system too well. I used parallel 1/0 instead of a single 2/0 cable. This was to lower the voltage drop across the wires in the battery side resulting in more of the pack voltage applied to the controller. More voltage on the controller = more current to the motor. He said the coil would prevent such a large surge as coils oppose current changes in a circuit, effectively limiting the surge current out of the drive and preventing it from going into over current and shutting down prematurely.
> 
> As far as the pack current goes, as it would only draw 90 amps, the motor circuit would pull close to or more than 500 amps. The coil will reduce that surge and allow the control to stay on longer.


Soooo...would this explain the couple jerks cutting in and out a bit from the controller on hard acceleration? 

Would this coil help extend the range or power somehow?


----------



## ElectriCar (Jun 15, 2008)

Well I didn't notice any power difference but it does run much cooler now. And that surging is the controller cutting back. It shouldn't be that way but it is.


----------



## Tesseract (Sep 27, 2008)

My $0.02... adding an air-core inductor to either the battery side of the controller (where it would arguable do some good) or the motor side is near useless at best, and a real EMI radiating menace to other electronics at worst.

Winding 10-12 turns of 2/0 on a coffee can is going to add something like 3uH of inductance... even deep into saturation the inductance of a WarP 9 is a good 50uH, so adding 3uH more to the motor loop ain't gonna do much.

My understanding is that the Curtis drops down in frequency at low motor speeds and high currents, as well as when hot, because its minimum on time is so long it loses control over the motor current (in other words, the throttle at low speeds would be very jerky).

Adding more inductance does help, because it slows the rise time of the current during the pulse on time, but adding 3uH, or even 10uH, is pointless. For example, if the motor inductance is 50uH and the desired motor current is 100A (trying to navigate a crowded parking lot) and the pack voltage is 144V it will take ~35uS to hit that limit. If you add 3uH more to the motor loop it will then take 37uS... hardly any difference at all.

Unfortunately, what adding more wire - especially in the form of a loop or a coil - will do is radiate MUCH more electrical noise, possibly to the point of interfering with _FM_ radio reception in nearby cars.

If you want to make your Curtis/Logisystems/Kelly (or other "shoe box" style controller) happier, try somehow to remove heat from it more effectively.


----------



## ElectriCar (Jun 15, 2008)

I don't know the calculated inductance but I've got 8 or 9 turns on a 5" od pipe. The reason I did it was because the control was getting hot and according to the engineer the coil would severely reduce the cause of this.

Apparently it was a good solution because after installing it I made two test runs of 2 miles with heavy throttle most of the way. Upon stopping the controller was barely warm. Before it would be pretty hot to the touch.


----------



## Tesseract (Sep 27, 2008)

Hmmm... It is really surprising to me that adding so little extra inductance would help so much. 

Would you mind doing a more controlled test with and without the coil? That is, measure the temperature of the controller before and after driving (also note the ambient) and try to drive the same route at the same speeds with the batteries fully charged each time.

The reason I am so surprised that only a few more uH of inductance would make the 1231C happy is that just taking a little more care in the design in the first place would render than moot. In other words, it implies a level of sloppiness in the engineering that I find difficult to believe given the sheer number of 1231Cs sold. I mean, all Curtis would have to do is speed up the switching speed of the MOSFETs so the minimum on time could be shortened. Of course there are tradeoffs to doing that, but if it only takes a few uH to make the 1231C a lot happier then the switching speed wouldn't need to be increased all that much to get the same effect.

Anyway, no sense second guessing the Curtis engineers... Just keep in mind that putting a coil anywhere in the high power wiring turns your vehicle into even more of a rolling FCC violation than it was.


----------



## ElectriCar (Jun 15, 2008)

Here's a letter from EVA about the coil received in my email. 

_The simplest DC electric drive system used a battery pack switch and a motor. When you close the switch, over 1000 amps of current would flow in the circuit, producing so much torque that it would break parts (axle, transmission, drive shaft or mounting brackets). So resistors were added to the early systems; this wasted energy but minimized damaging parts. Modern controllers make are better because there is an electronic switch that turns on and off so fast that it can control the current through the motor and the torque it produces. Most of the time, the motor and controller work well, but it is difficult to identify exactly how they will work together. 

With the large number of systems we sold last year, now in operation, some customers (~1%) have run into some operating problems, such as a periodic burp in the system. Dave Mosher of Custom Electronics has determined that these problems were due to low inductance in the system. Inductance can be added to the system by making an inductive coil. _

_The instructions are: 

Make a coil of 2/0 cable using about 10 ft of cable by wrapping it around a coffee can or PVC pipe; then wire tie the coils together. Remove the coffee can-it is metal. Connect this coil between A2 and S2 on the motor (CCWDE), replacing the existing short cable that connects the field and armature in series. If the motor is set up for CWDE, then the terminals will be A1 and S2. This coil does not need to be beside the motor, so you have some flexibility in location. Use quality lugs and heat shrink.

The addition of an inductive coil eliminated the operating problems that these few customers encountered. We are fine tuning the existing system. Adding an inductive coil to the motor circuit will be beneficial for all of our customers, because it will decrease the heat in the controller and motor and possibly provide additional range. To date, the inductance coil has been implemented on a few vehicles with no negative results._


----------



## palmer_md (Jul 22, 2011)

skipping the conversation regarding motor inductance...has anybody had this upgrade performed to their 1231c? I got a quote for $650 to upgrade to 1200 amps while remaining at 140v on my battery pack. Seems like it might be worth it for my old car to try and get an inexpensive boost. 

I've been wanting to upgrade to a Soliton1 and doubling the pack voltage and then swapping to an 11hv. Seems like this upgrade might just do the trick. I'd get to see what is is like to have more power for a short while until I blow my ADC9". Then upgrade the motor, and then the controller after it burns up, then the batteries.

I'm really curious to see if anyone has done this and how long it lasted after the upgrade was performed.


----------



## ElectriCar (Jun 15, 2008)

Tesseract said:


> My $0.02... adding an air-core inductor to either the battery side of the controller (where it would arguable do some good) or the motor side is near useless at best, and a real EMI radiating menace to other electronics at worst...


I'm getting one of your controllers. The "upgrade" to my Curtis fixed my overheating problem but I can't seem to keep it from blowing mosfets. The last repair lasted <300 miles. 

So I can remove this coil, my contactors and my precharge gear. Will make for a much cleaner install.


----------



## ElectriCar (Jun 15, 2008)

palmer_md said:


> skipping the conversation regarding motor inductance...has anybody had this upgrade performed to their 1231c? I got a quote for $650 to upgrade to 1200 amps while remaining at 140v on my battery pack. Seems like it might be worth it for my old car to try and get an inexpensive boost.
> 
> I've been wanting to upgrade to a Soliton1 and doubling the pack voltage and then swapping to an 11hv. Seems like this upgrade might just do the trick. I'd get to see what is is like to have more power for a short while until I blow my ADC9". Then upgrade the motor, and then the controller after it burns up, then the batteries.
> 
> I'm really curious to see if anyone has done this and how long it lasted after the upgrade was performed.


Here's my review of this "mod". 

I have about 3000 miles with this mod. 

Pros:


Doesn't overheat anymore


Will apply more torque than my transmission can withstand if the tires didn't break traction
Is cheaper than a new controller
Cons:


I've blown 3 400A fuses and been towed three times.
It's been "repaired" twice and won't go back on my truck.
May be that the batch of mosfets that were installed in my controller were from a bad batch, IDK. He's offered to replace the lot of them but I'm gun shy now and have had enough of the inconveniences and removal, mailing it back and reinstalling it. You decide what's best for you...


----------

