# debugging Zilla cutting out - where to look for diagnostic codes ?



## dtbaker (Jan 5, 2008)

my eMiata is 'cutting out' under small loads. I barely made it up the driveway as it would cut out, turn off, and I had to key-off, cut main battery circuit, and reset to turn on again.

I suspect there is an error code or diagnostic somewhere in the hairball that may help me track down the issue, but it's been so long since I set it up, I kind forgot how to dig into it. I am pretty sure I can find my old laptop, as I saved it just to talk to the hairball.... I thought I'd put the issue to the Forum, and see if the collective brainpower can speed my debugging.

my build basics:

'94 Miata (NA), conversion complete 2012, about 28k electric miles on it now
160v nominal (48 x 130ah CALB cells)
Zilla 1k, circa 2011

Symptoms:

- I can key-on, everything looks normal.... I can throttle rpms up when in neutral no problem.... I can put in gear, and start moving, but something cuts power OFF as soon as there is much load. Zilla errors out, and will not reset until I cut main battery and reset hv and lv power. Note that I have always run my dc system direct from dc-dc converter, with NO battery inline.

- I did notice my ABS indicator flashing, and thought is was probably just a bad sensor as I had notice some metal filing collecting on ABS ring on rear hubs last time I adjusted parking brake.... but I noticed there was a pattern to the blinks. In this particular install, I think the warning lights are wired to the hairball for a visual display of error codes, but I couldn't find any documentation. I was seeing blink----pause----blink-blink----pause---blink

- then, since I had it parked, I went to power it up to dig in, and the ABS relay started buzzing. This made me start thinking maybe its just an ABS issue, but confusing since the hairball was killing power when I was not touching brakes.

What I've tried so far:

- thinking dc-dc converter might have gone bad (I've placed it once before), I swapped in a new one..... didn't help.

What's next:

- any ideas what to look for in Zilla terminal screen, assuming I can get that going ?

- would it be possible for bad ABS to be screwing up the Zilla? How can I disable ABS signal to test this?


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## kennybobby (Aug 10, 2012)

If you had a 12V starter battery in your system, then i would have guessed it was old, weak or worn out and sagging too much and couldn't hold up the necessary loads.

But since you are on a DC Converter from the High Voltage, i would suspect that you have one or more weak cells in your pack that is causing the pack to sag under load. And it may be causing the DCC output to sag with the same issues of a weak 12V battery (e.g. ABS fault), plus causing issues with a low or sagged HV input to the motor controller.

Just my troubleshooting 2¢,


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## dtbaker (Jan 5, 2008)

kennybobby said:


> If you had a 12V starter battery in your system, then i would have guessed it was old, weak or worn out and sagging too much and couldn't hold up the necessary loads.
> 
> But since you are on a DC Converter from the High Voltage, i would suspect that you have one or more weak cells in your pack that is causing the pack to sag under load. And it may be causing the DCC output to sag with the same issues of a weak 12V battery (e.g. ABS fault), plus causing issues with a low or sagged HV input to the motor controller.
> 
> Just my troubleshooting 2¢,


not a bad guess, but I have display of both HV and LV right in front of me..... Zilla cuts out with very low loads (like 5-10amps on HV side), so there is basically no sag on either HV or LV when it cuts out.


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## kennybobby (Aug 10, 2012)

How about a bad or weak cell with high IR that is limiting current of the pack?


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## dtbaker (Jan 5, 2008)

kennybobby said:


> How about a bad or weak cell with high IR that is limiting current of the pack?


nope.... very doubtful.

I have voltmeters permanently attached to all 48 cells, and can see them. all good voltage, and none show huge voltage drop when zilla kicks off (at low current, and almost no load)

what I am really looking for at this point is a quick refresher from somebody familiar with the Zilla terminal and diagnostics. I can't remember exactly how to get in, and not sure where my documentation is on the Zilla diagnostic codes. At this point I don't know if the Hairball has recorded any errors or not since I can't remember how to get in.


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## Ken S (8 mo ago)

You'll need an RJ-11 cable to connect to the RS-232 interface on the hairball. Then an RJ-11/DB-9 adapter, and perhaps an RS232/USB adapter. Then you can connect from your PC using a terminal program (minicom, etc).

The Zilla manual is here: DOWNLOADS . The diagnostic codes are on page 19.

If you're running Windows, there is an old GUI called ZillaView

You may want tor read this thread.


diggerdave said:


> Great! just to be clear the length of the wires is not a problem as long as both wires are the same length and have exactly the same paths. The HB is measuring the resistance of the contactor points and comparing them and will open the contactor if the measured resistance of each is not within prescribed tolerance. Thus length and path being EQUAL are what's critical.


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## dtbaker (Jan 5, 2008)

Ken S said:


> You'll need an RJ-11 cable to connect to the RS-232 interface on the hairball. Then an RJ-11/DB-9 adapter, and perhaps an RS232/USB adapter. Then you can connect from your PC using a terminal program (minicom, etc).
> 
> The Zilla manual is here: DOWNLOADS . The diagnostic codes are on page 19.
> 
> ...


the link to the manual is a good start as I cannot find the one I used when I built the system.... I did find the box with the cabling, and the old laptop I had used to run the terminal program.

This system was working fine, for a long time, so unless I can find a loose connection, or possibly a mouse-chewed wire, I don't think any of the wire run resistance has changed. But the car has been outside for a while and mice and ground squirrels are in the area.....


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## Ken S (8 mo ago)

Is the main contactor an open-frame device (like an albright contactor)? If so, any dirt on the contacts could result in a voltage drop across the contactor when the current is high.

Personally, I think voltage sag is more likely. In any case, the diagnostic codes will tell you whether and why the the system opened the main contactor.


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## dtbaker (Jan 5, 2008)

Ken S said:


> Is the main contactor an open-frame device (like an albright contactor)? If so, any dirt on the contacts could result in a voltage drop across the contactor when the current is high.
> 
> Personally, I think voltage sag is more likely. In any case, the diagnostic codes will tell you whether and why the the system opened the main contactor.



contactor is open frame, but as noted in top post the controller is killing power under LOW loads, with no voltage sag. The controller is not opening the contactor, it is 'erroring out', and killing power internally until I physically key-off, depower the controller w main breaker to re-set, re-power, re-key-on.

.... but I will inspect contactor surfaces for pits, burns, and debris.

and post what I find in diagnostics, probably not until the weekend....


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## gdirwin (Apr 7, 2009)

Had similar issues, and ending up being brush issues... Have you looked at motor brushes? 

Hairball error codes are here: https://evwest.com/support/zilla manual 2.02d.pdf - edit - earlier link from the OEM is the better definitive source...


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## jwr813472 (Jun 1, 2010)

I had a similar issue with mine cutting out while climbing hills. No faults on the Zilla 1K. As with gdirwin posted above , it was a brush issue. They weren't very old so I swapped all the brushes inboard to outboard and haven't had a problem since.


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