# voltage limits for Curtis1231 w/ ADC 9" ?



## socko (Sep 21, 2008)

The answer to this question is probably on this site somewhere so sorry if I missed it.

As I upgrade my build from lead to lithium, I plan to go from 96 volts to 170 volts. I plan to also upgrade motor and controller but not until later. So the question becomes:

Can the Curtis 1231 controller and Advanced DC 9" motor handle 170 volts for a few months until I get an upgrade? 

Surely someone has tried pushing these limits?

Cheers,
Brandon


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## EVfun (Mar 14, 2010)

There are 2 models of 1231C controllers. One is rated for 120 volts with a peak current of 550 amps. The other is rated for 144 volts with a peak current of 500 amps. 

I would not recommend exceeding a 40 cell (in series) pack with the 120 volt model or 48 cells with the 144 volt model. Some people try to push a controller to the very upper limit but the manufacturer put those rating on there for a reason.


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## Ziggythewiz (May 16, 2010)

For starters...you shouldn't experiment with a controller you can't afford to lose.

The 1221-C, rated at 120 has components rated at 160, so I run mine above 120, but not much. As has been stated, the buffer is there for a reason.
I really have no idea, but if I had to guess I'd expect the 144V 1231 to have internals rated at 200V.

If you run it over spec, it is guaranteed to fail sooner than if you run it within spec. Could it last a few months? Maybe. The controller should be able to protect itself from excecssive overvoltage. If you give it too much it shouldn't turn on. The limit will likely be set at what Curtis considers the max safe voltage, is that as high as 170? Who knows?


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## peggus (Feb 18, 2008)

My Curtis 1231C will not run above 170V. At 175 it will not respond to throttle and at 170 it will run but it never gets out of the squeel mode. It seems I need to be below about 168V for it to operate normally.

So depending on whether 170V is your full pack voltage or your nominal pack voltage, it may work.


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## Ziggythewiz (May 16, 2010)

That's interesting, so they have the limits around 85% of (what I assume is) internal capacity. I've had my 1221 up to 90% of it's internals without hitting the limit. Definitely not going to look for it, or even take it that high again...


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## socko (Sep 21, 2008)

Thanks for your quick replies - it's so helpful to get real-world feedback.

So if the 1231 accepts the voltage, I need not worry about the motor's voltage limits?


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## Weisheimer (May 11, 2009)

gottdi said:


> ...What is with the choice of 170 volts? Odd. Who planted that idea?


Probably the 50 LiFePo4 cells and matching charger that he has...
So, 168 vdc nominal pack voltage if counted at 3.36vdc resting voltage per cell and 182.5vdc at the end of charge.
Perhaps you could borrow the Soliton1 for a while until you could go with something different?
Can you tell us what the full model number of your 1231C is?

Mark

BTW Brandon, I really enjoy your video work.


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## socko (Sep 21, 2008)

Hi Mark! 

Sorry, I should've been more specific: it's the 1231C-8601.

At this moment, I'm thinking of buying a friend's used Zilla 1k HV for the interim. If that works out, I would guess that it would get a lot out of that 144-volt motor. And it can dial down the current when in reverse so I don't break another vintage transmission! 

THanks for the compliment. Hope to catch you at EVCCON again!

cheers,
Brandon


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## socko (Sep 21, 2008)

I learned today from someone who sells Curtis products that 180 volts should be fine. 144v x 125% = 180v. Which unfortunately contradicts it not operating at 170+.

:/

Thanks for all your feedback though.

-Brandon


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