# fine tuning the curtis 1268 to 4kw sepex



## Rodster (Apr 28, 2010)

I've spent quite a bit of time reading the Curtis manual. I have a new 25 mph NEV (street golf cart). I've been playing with the parameters per the manual but I'm looking for some advice on fine tuning the motor for slightly higher speed and not frying the motor in the process. 

When I test the Arm PWM it's at 100% which means the speed is limited by the field map parameters. I've set the Field Map Start to 180 (generic setting is 100) which is slightly above the Arm Current reading. Fwd FLD min is 3.5 so it's pretty low already. What I found is that my speed increased about 4 mph and the acceleration to top speed was much quicker. What I am trying to determine: Is 180 too high for a Field Map Start? Since the Arm PWM is still at 100% am I maxed out for speed on this motor? (If I let off the pedal slightly and slow down 1-2 mph Arm PWM drops into 90's)

Field Max is set at 45. Field map end at 280. field ramp is at 40. 

There is no info on this particular motor other than 4kw 5.5hp, made in China. I measured the field resistance cold at 1 ohm and calculated 1.2 Hot. 
There is no info on max arm current rating or max/min field current ratings that I could find in my searches. It would help if I knew what they were so I know what safe parameters would be to run as I max this thing out. 

Anybody?


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## major (Apr 4, 2008)

Rodster said:


> I've set the Field Map Start to 180 (generic setting is 100) which is slightly above the Arm Current reading. Fwd FLD min is 3.5 so it's pretty low already. Anybody?


Hi Rod,

Try Field Map Start = 120 and Fwd FLD min = 3.0 (maybe as low as 2.8) and see what happens. Let me know.

Do you have a Field Map Midpoint parameter setting on that model?

major


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## Rodster (Apr 28, 2010)

major said:


> Hi Rod,
> 
> Try Field Map Start = 120 and Fwd FLD min = 3.0 (maybe as low as 2.8) and see what happens. Let me know.
> 
> ...


Thanks for the response Major. 

The Field ramp apparently uses the midpoint in adjusting the % of field current to arm current. It's currently set 50 but I think I will move it back to 40. At 30 I lost top end. 


I'll let you know on the other settings.


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## Rodster (Apr 28, 2010)

Field start is at 120, fwd field min at 3.0, ramp end at 280, field max 35, field ramp 40. 

Runs about 26 mph. I didn't try 2.8 since the programmer apparently steps by .5 since it only accepted 2.5 or 3.0 so I left at 3.0. 

I'm thinking there are some tweaks to be done on the ramp and maybe field max (which as I understand also shapes the field map) I left the FM at 35 and tried ramp at 30 and lost speed and acceleration. At ramp 50 great acceleration but lost a little top end. So I went back to 40.


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## Rodster (Apr 28, 2010)

Rodster said:


> Field start is at 120, fwd field min at 3.0, ramp end at 280, field max 35, field ramp 40.
> 
> Runs about 26 mph so about 3 mph slower. I didn't try 2.8 since the programmer apparently steps by .5 since it only accepted 2.5 or 3.0 so I left at 3.0.
> 
> I'm thinking there are some tweaks to be done on the ramp and maybe field max (which as I understand also shapes the field map) I left the FM at 35 and tried ramp at 30 and lost speed and acceleration. At ramp 50 great acceleration but lost a little top end. So I went back to 40.


I'm guessing this is a trial and error deal to find out your most efficient map shape since I don't have any manufacture specs on the motor, just generic info that I have used from a similar motor from ADC.

Any other helpful hints in tweaking these little motors?


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## OBeer-WAN-Kenobi (May 28, 2010)

Rodster,
Do you have a Zone electric car? I'm still waiting for the delivery on mine but will be interested in tweaking it as well if anyones got some good info.


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## Rodster (Apr 28, 2010)

Yes. You will like it when you get it. Have you stopped in at Nevzone yet? Lotsa good info on the Zone carts and easy DIY mods.


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## OBeer-WAN-Kenobi (May 28, 2010)

Rodster said:


> Yes. You will like it when you get it. Have you stopped in at Nevzone yet? Lotsa good info on the Zone carts and easy DIY mods.


Haven't signed up but have been lurking......

I'm particularly interested in installing a mode switch so I can have a high torque low speed mode and a higher speed lower torque mode.


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## Rodster (Apr 28, 2010)

I'm not aware of a seperate field map setting for M2 on the Curtis controller. You can set the M2 field minimum and M2 speed but your ramp and field max are universal. My understanding is torque will be the same for both hi and low speed settings for a sepex. If you don't need the low speed switch option you can omit it since the low speed torque will be the same for both hi and low settings anyway. 

But, I could be wrong and maybe someone knows how to program the Curtis controller for that purpose. 

I'm still testing for the optimum field ramp settings.


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## OBeer-WAN-Kenobi (May 28, 2010)

Rodster said:


> I'm not aware of a seperate field map setting for M2 on the Curtis controller. You can set the M2 field minimum and M2 speed but your ramp and field max are universal. My understanding is torque will be the same for both hi and low speed settings for a sepex. If you don't need the low speed switch option you can omit it since the low speed torque will be the same for both hi and low settings anyway.
> 
> But, I could be wrong and maybe someone knows how to program the Curtis controller for that purpose.
> 
> I'm still testing for the optimum field ramp settings.


Signed up at NEVzone the other day.

I think that you are right about the field map. I am just worried by a few people saying that they didn't have enough oomph to get up ramps onto a truck without taking a run at it. I think I will use the torque more than the high speed most of the time. My Zone (if I ever get the friggin thing) will be used primarily off-road as a utility vehicle.

I suppose I could just get a series motor and controller and switch it out. Something nice and torquey, that'll drain my batteries in 5 minutes...


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## OBeer-WAN-Kenobi (May 28, 2010)

Hey, I think I got a hold of a field map courtesy of one of my friends in China. Maybe major can make something of it and help us out??



PM inbound......


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## major (Apr 4, 2008)

OBeer-WAN-Kenobi said:


> Hey, I think I got a hold of a field map courtesy of one of my friends in China. Maybe major can make something of it and help us out??


Hi OB,

Looks like a performance curve, not field map. Not much use 

major


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## OBeer-WAN-Kenobi (May 28, 2010)

major said:


> Hi OB,
> 
> Looks like a performance curve, not field map. Not much use
> 
> major


Darn it! Can you show me a good example of what a field map should look like? Obviously I don't know what I'm looking for  and I'm communicating across a tech jargon barrier and a language barrier to try to get the info we need to fine tune our controllers.


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## Rodster (Apr 28, 2010)

It looks like a performance curve but it's interesting anyway. 

I've been running with a ramp of 25 and it seems to do very well on that. Higher ramps give me a bit of lag at low end acceleration. I don't understand why that is.


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## Rodster (Apr 28, 2010)

OB- see if you can get the max Field current and arm current specs, along with min fwd FC. How about FC for specific points of output along their performace graph?


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## major (Apr 4, 2008)

OBeer-WAN-Kenobi said:


> Darn it! Can you show me a good example of what a field map should look like? Obviously I don't know what I'm looking for  and I'm communicating across a tech jargon barrier and a language barrier to try to get the info we need to fine tune our controllers.


Hi OB,

Here's my attempt to insert a Field Map lifted from a Sevcon SepEx manual.


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## OBeer-WAN-Kenobi (May 28, 2010)

Xie Xie (Thanks) Major! 
I sent that to my friend as an example. He also knows nothing about electric motors (just like me) so hopefully it will help him communicate with SuZhou.




Rodster said:


> OB- see if you can get the max Field current and arm current specs, along with min fwd FC. How about FC for specific points of output along their performace graph?


I've listed your requests along with the field map major provided in an email to my friend. I don't want to get him too confused though. Even though he speaks English very well and I know a little bit of Chinese, it's still a little tough communicating with technical stuff.


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## Rodster (Apr 28, 2010)

OBeer-WAN-Kenobi said:


> Xie Xie (Thanks) Major!
> I sent that to my friend as an example. He also knows nothing about electric motors (just like me) so hopefully it will help him communicate with SuZhou.
> 
> 
> ...


This will be cool if we can cobble enough info to maximize the little motor. I also want to see if my test results are close to what they say the map should look like.


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## OBeer-WAN-Kenobi (May 28, 2010)

I'm cross posting this from Nevzone in hopes of an answer. I Ran into a little problem. I can't connect to my controller. I'm running Win7 ultimate on a lenovo netbook and I'm using ain IOgear USB to serial converter with a homemade cable. I rechecked the cable twice with my multimeter to make sure it was wired right. I was able to get the curtis software to autodetect the port but it always gave me an E0023 (I think) communication error.

I tried with key on and off, tow-run, on and off and still wouldn't work. Any ideas?


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## jmekeel (Sep 3, 2010)

What are you guys using to reprogram the controller? I'm sitting here in New York looking for someone to reprogram the 1268 Curtis i have in My cart.


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## jmekeel (Sep 3, 2010)

Is anybody getting more torque from these motors? I have 22" tires on this thing and they cannot pull hills. The motor stalls with 2 or more people on them.


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## major (Apr 4, 2008)

jmekeel said:


> Is anybody getting more torque from these motors? I have 22" tires on this thing and they cannot pull hills. The motor stalls with 2 or more people on them.


Hi jmek,

Yeah, they worked well on some IUVs I made. What size vehicle is it and what type of ratio do you run?

major


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## jmekeel (Sep 3, 2010)

It is a Zone Electric 4 seater, 5.5hp 4kw motor, curtis 1268 controller, 10.25 gears, 6 inch jakes lift with 22" tires.


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## major (Apr 4, 2008)

jmekeel said:


> It is a Zone Electric 4 seater, 5.5hp 4kw motor, curtis 1268 controller, 10.25 gears, 6 inch jakes lift with 22" tires.


What does Zone say? Are those original tires? Battery any good? Could be lots of things.


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## jmekeel (Sep 3, 2010)

original tires were 18", the lift and 22" tires is a package they offer. They have no clue that's why I'm searching the forums. If I could figure out what axle I have in the rear I would change the gears. But i was also hoping to reprogram the controller for additional torque.


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## major (Apr 4, 2008)

jmekeel said:


> original tires were 18", the lift and 22" tires is a package they offer. They have no clue


I'd insist for a refund from Zone and buy a cart from a company which does have clues.



> If I could figure out what axle I have in the rear I would change the gears.


This might be possible. Doesn't the owner's manual have the axle P/N? Doesn't Zone know which axle they used?



> But i was also hoping to reprogram the controller for additional torque.


Depends on where you're set now. Often more torque comes at the expense of more current, which may not be in the cards. Again, Zone should know this.

And you didn't the answer battery question. Often times, problems like this can be as simple as a flat battery. If it doesn't have a voltmeter on it, get one. And ammeter would also help guy like me diagnose a problem from afar.

Regards,

major


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## jmekeel (Sep 3, 2010)

Battery's are new the cart is only a month old. I assume the battery's are fine.


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## major (Apr 4, 2008)

jmekeel said:


> Battery's are new the cart is only a month old. I assume the battery's are fine.


Assumptions are bad things to use when trying to solve problems. My experience with the best batteries money can buy is that 1 to 2 % fall flat on their face out of the box. And you think Zone used the best batteries? A more common rate might be on the order of 5%. How many you got in there? 6, or 8? Do the math. Probability is significant enough not to rely on an assumption.

major


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## jmekeel (Sep 3, 2010)

8 Batteries, they are US 250HC XC


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## major (Apr 4, 2008)

jmekeel said:


> 8 Batteries, they are US 250HC XC


So what is the voltage no load vs 200 amps?


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## jmekeel (Sep 3, 2010)

major,
I'm not big on these electric carts, so where would I check the voltage output?


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## major (Apr 4, 2008)

jmekeel said:


> major,
> I'm not big on these electric carts, so where would I check the voltage output?


Assuming you get a voltmeter with probes, check each battery. They should be all the same. Then you need to somehow wire the voltmeter to the most negative terminal and the most positive terminal so you read somewhere around 52 volts. {Assuming you have 8 six volt batteries} Then you need to see how that voltage falls when you put it under load, like going up the hill. That is where it would be nice to see the current, ie. ammeter.


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## jmekeel (Sep 3, 2010)

ok, so I didn't remove all the wires to check each battery but I did connect to the final end battery wires going to the motor. I got 50.8 - 51 volts stopped. I drove on flat ground and it dropped to 47 - 48. Going up a steep hil it dropped to 44-45 and when I tried a reallt steep incline the motor stalled and it read 48-49 volts. Going down hill it jumped up to 51-52 volts, I guess that is regen mode.


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## major (Apr 4, 2008)

jmekeel said:


> ok, so I didn't remove all the wires to check each battery but I did connect to the final end battery wires going to the motor. I got 50.8 - 51 volts stopped. I drove on flat ground and it dropped to 47 - 48. Going up a steep hil it dropped to 44-45 and when I tried a reallt steep incline the motor stalled and it read 48-49 volts. Going down hill it jumped up to 51-52 volts, I guess that is regen mode.


Good for you. Real data. Those batteries don't seem great, but should not be bad enough to cause controller cutback. But hard to know for sure without seeing how the controller is set up. But for now anyways, I wouldn't blame the batteries.

So I don't know what to tell that I haven't already said. Put a big sign on it with your problem and park it in front of the dealer where you bought it. Maybe that will get some attention from Zone.

Sorry, anyone else have a clue 

major


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## E4mula (Mar 31, 2009)

You can try pulling the field cables off the motor and measuring the field resistance, it should be somewhere around 1ohm. Then reconnect the field cables and try measuring the voltage across the field windings when you are stalled on the hill. This should give you an indication of your field current.

If the voltage across the field is close to your battery voltage, then your motor may be maxed out and just doesn't have enough torque to climb the hill you're trying to go up.


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## krusty0001 (Sep 13, 2010)

Hi everybody. I'm new to DIY, but seen a lot of folks in this thread elsewhere. 

JMK, if you want to reprogram your 1268, before making any changes, grab the monitor logs from the controller. It'll definately let you know what is happening when you stall on that hill. There is only so much these high speed motors with high speed gears can do. 

Here are my suggestions for more ZONE torque:
1) change main c/l limit from 300 to 400
2) change field map end from 280 to 200
3) change field max from 30 to 45
4) change m1 accel from 2 to 1

When stalling up that hill, my guess is you've exceeded 300A arm current. The controller is software limited by the main c/l parameter. It won't output any more. Suggestion #1 will take you above 300. 300A is huge and you need to drive that number down with more field (#3). 

I'd be very cautious of running large arm currents for long. The biggest hill in my neighborhood, I run 150-275A arm currents, 15-28A field, for 15s. My speed drops from 17 to 10mph. I'd say 275A for 10s is safe. You might be able to go higher for longer, but I don't know.

The (reposted) picture below is hill testing while changing the field min parameter. The relationship between field currents, arm currents, and speed can be seen. More field= less arm= less speed.


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