# Zilla Desat Error 1122



## jaspersk (Jun 26, 2008)

I drove my car on lead for a year without problems before putting into storage for two years (temporary move). I recently got the car back on the road with LiFePO4. I have taken it for probably 10 trips. One two separate occasions several seconds into accelerating from a stop sign, the Zilla tripped out. My max battery amps are set to 800 but I am fairly certain I didn't come anywhere close to that. 400 or maybe 500 amps as worst.

Error codes:
1122 Controller Desat error
1133 Lost Communication with controller during use, either direction

There are only a small handful of posts on this error code and they all suggest this is very bad. I sent a note to Zilla support but wondering if anyone hear might have experience with this.


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## Tesseract (Sep 27, 2008)

A desat error usually indicates one of two things has occurred: a short in the motor circuit (either in the motor or its wiring) or a failed power stage. 

Is the controller still operating normally EXCEPT for occasionally tripping a desat error?


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## jaspersk (Jun 26, 2008)

Tesseract said:


> A desat error usually indicates one of two things has occurred: a short in the motor circuit (either in the motor or its wiring) or a failed power stage.
> 
> Is the controller still operating normally EXCEPT for occasionally tripping a desat error?


The controller is operating normally once the error code is reset. 

Now that you explained this, it made me remember that I increased the motor amps setting on the controller when I installed the Li batteries. The amp limit is currently set to 1000 amps which is the controller limit. A DC motor is a short circuit at zero speed right? I have been taking off from stop in 3rd gear (maybe I was in 5th?). The low motor RPM's probably gave me a low back EMF which might not be a short circuit but possibly enough to push the controller over the edge with the maximum current set so high. If simply reduced my motor amp limit to something around 800 amps and started off in a lower gear when I want the harder acceleration, would that likely solve the problem?


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## Tesseract (Sep 27, 2008)

jaspersk said:


> ...A DC motor is a short circuit at zero speed right?


To pure DC, yes, a motor at 0RPM looks like a dead short, but motors have significant inductance and this resists any rapid changes in current if the DC is PWM'ed (like from a motor controller). Your Zilla shouldn't have any problem with this so I'm thinking you might have a noise problem. If the problem goes away when you reduce the current limit back to 800A then I'd be even more inclined to say it is noise. The Zillas need a very good ground connection for the 12V supply and a ferrite "snap-on" choke for the cable connecting the Hairball to the power stage.


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## Otmar (Dec 4, 2008)

Tesseract said:


> so I'm thinking you might have a noise problem. If the problem goes away when you reduce the current limit back to 800A then I'd be even more inclined to say it is noise. The Zillas need a very good ground connection for the 12V supply and a ferrite "snap-on" choke for the cable connecting the Hairball to the power stage.


I don't visit this forum often, but it sure is nice that when I do I see my competitors providing tech support for my product. What great guys!

Yes, it's probably noise. Sometimes carbon/dirt from the motor connections to chassis can cause some pretty tremendous noise between the battery system and chassis 12V. We had a couple motors that internally shorted to chassis when they were melting at Tucson and that showed up as various errors including 1122. Also if your wiring layout is poor then increased motor current might push the noise over the edge to trip an error. 

Older Zilla's (pre 2008? I forget..) can have a failing gate drive power supply that starts out by throwing desat errors. A request to zilla tech support with your serial number might be able to find out if it has the old style DC-DC and therefore could benefit from an upgrade. Fortunately when they fail they shut down and so far I have not seen them blow up from that failure mode. (fingers crossed that the build in protection holds)

It is possible to get a Desat error from overcurrent, but it takes many thousands of amps to do that. A Z2K takes about 18,000 amps before it trips. I only had it happen when I shorted the motor output while at full power.


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