# diagnosing possible Zilla failure - help needed



## dtbaker (Jan 5, 2008)

I've been happily driving my eMiata for 13,000 miles... but now have something serious wrong. I'm starting this thread in hopes some of the more experienced Zilla users have some ideas to help me determine the problem and options.

My build in a nutshell as applies to this discussion:

- 156v nominal battery pack - 48 x 100ah CALB cells originally. I lost one cell at about 10,000 miles when I let a friend drive the car for a while and they ran the pack down until the car stopped moving.

- zilla Z1k LV. manual I have says rev 2.9.05 v2.02a, using HEPI throttle.

- The original build was mostly done by someone else, I just upgraded it from 144v lead-acid to Lithium. I have not gone thru all the hairball wiring because it seemed to be working just fine. For instance, on review now, I don't see any 'snubber diodes' in the main contactor wiring between contactor and hairball.... but since I didn't do the install, I'm not quite sure what to look for.

SYMPTOMS:

was accelerating from a stop and there was a POW sound and jerk feeling... main circuit breaker flipped off. I reset, and it seemed to stagger a bit, drove very gently for a bit, then jerked and errored out.

I've checked brushes, and they appear 'ok', although look to be set at more of an angle than I would have expected. The top of the front set were level with top of holder, the inner brushes were about 1/4 inch above holder, so I swapped positions as I inspected.

The error lights on the hairball do do go out, and the contactor does not contact to close the circuit when I key-on.
- main cont off - amber
- precharging - red
- main cont on - off
- error - red

DIAGNOSIS

I do have the ethernet a serial cable still, and an old windows laptop with hyperterm. I used this to set volt/amp limits, but have never attempted to figure out the diagnostic codes.

Any advice on viewing/interpretting codes?
Any ideas on what might be wrong? 
Is there a place we can send hairball/main unit for diagnosis/repair?


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## major (Apr 4, 2008)

http://www.manzanitamicro.com/home

Rich Rudman's company. They handle the Zilla product line now. In house manufacturing, testing, sales, support and repair. Good people. Give 'em a call. 

major


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## dtbaker (Jan 5, 2008)

major said:


> http://www.manzanitamicro.com/home
> 
> Rich Rudman's company. They handle the Zilla product line now. In house manufacturing, testing, sales, support and repair. Good people. Give 'em a call.
> 
> major


good to know, I will!

...anybody else out there that may be familiar enough with the hairball error interface to help me step thru how to extract and interpret the error codes?


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## EVfun (Mar 14, 2010)

Since you have set the current I'm guessing you know how to bring up the Zilla in a terminal program on the Laptop. The basic settings for the terminal program are, "The Hairball speaks 9600 baud, no parity, 8 bits, 1 stop bit. It does not use flow control of any type (turn off both Xon/Xoff and RTS/CTS.)" [from the manual page 13] From the main Zilla menu type a lower case d and hit return. That will display the settings including the last 4 error codes. Record those codes and look them up using the Zilla manual page 19. If you do not have a manual, or it is so old the page numbers I've given don't work you can download the current version from Manzanita Micro here.


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## dtbaker (Jan 5, 2008)

EVfun said:


> Since you have set the current I'm guessing you know how to bring up the Zilla in a terminal program on the Laptop.


I did find my manual, fired up the old laptop (still running windows that had hyperterm!) and checked error codes.

1141 1213 1213 1223 1131

I cleared, turned key-on, and got another 1131 which is 
'shorted/loaded Controller during precharge'.

This does not sound good at all, but would explain the bucking and tripping if it is internally shorted full-on.

I am wondering now if it is most likely a hairball problem or just the controller itself. I actually have a spare on the shelf I was saving for my next build, but I might just swap it in. I'd rather not pull the hairball as it has a lot more wiring to undo and redo, but am thinking maybe I should just to verify all the wire runs and make sure the original builder put diode snubbers in there somewhere; I'm not seeing any, and not quite sure what to look for.

can someone please take a picture of 'diode snubbers' mentioned in the manual, and perhaps show where they are in their circuitry? I may end up pulling the hairball, controller, and contactor board to re-check all the LV wiring.


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## EVfun (Mar 14, 2010)

A wiring check comes to mind. Make sure the 2 wires on the end of the Hairball that are for the precharge connection go directly to the power terminals of the main contactor. Being wired to equivalent nearby points in the high voltage wiring is not good enough. It is a funny thing about the Hairball.

I had those wires going to a pack plus 30 amp fuse and the controller side of the main contactor on my Datsun conversion without issue. I wired it up the same in the Buggy and had most of those errors you show. Putting the pack + side of the precharge on the other side of the charger to car fuse means nothing electrically when the off board charger is unplugged, and pulling that fuse and the DC to DC fuse allowed the car to be parked with zero pack load. Still, in one case that worked fine and in the next the controller didn't want to turn on (with either 1131 or 1141 errors if I remember correctly.) When it did turn on it would shut off as I opened the throttle (with high contactor resistance errors.)


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## dtbaker (Jan 5, 2008)

EVfun said:


> A wiring check comes to mind. Make sure the 2 wires on the end of the Hairball that are for the precharge connection go directly to the power terminals of the main contactor. Being wired to equivalent nearby points in the high voltage wiring is not good enough. It is a funny thing about the Hairball.


two wires from contactor terminals run directly to hairball... no fuses, spade connections or anything else between.

Any other things to look out for?

I am wondering specifically about the 'snubber diodes' mentioned in the manual, but not shown in any schematic. where are they supposed to go, and what do they look like?

In the past I had an issue with the 14+v input not being good enough under certain conditions... the controller would shut down, usually only at night if I turned on headlights before the car was moving. Never a problem if I turned on headlights after moving, which I never did figure out.


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## dtbaker (Jan 5, 2008)

this evening, I got the controller out of the car, but left in the hairball for now.

Is there any gross test procedure I can do on the controller terminals to verify that it has an internal short or is stuck 'on'?

I am debating on whether it is worth the time to remove the hairball and replace with my spare, or just swap in the controller spare and put it back together...


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## major (Apr 4, 2008)

dtbaker said:


> this evening, I got the controller out of the car, but left in the hairball for now.
> 
> Is there any gross test procedure I can do on the controller terminals to verify that it has an internal short or is stuck 'on'?
> 
> ...


Hi Dan,

We used to test for shorted IGBTs with the old style Simpson analog meters. I don't know if that works on mosfet controllers, or even what is in your Zilla. Maybe you could get info on that by calling Manzanita.

Also, on page 3, item 7 of Zilla Owners Manual, it claims contents include contactor snubber diode(s) and in bold: It is very important to use them. 

These are more than just a standard diode which can slow turn-off of the contactor, so use the one from Manzanita. Call and they will send you a couple for a few bucks. It is wired across the contactor coil.

major


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## dtbaker (Jan 5, 2008)

Finally did get to speak with Rich today... really nice guy. I will be sending both my hairball and controller for inspection/repair.

It is 'likely' that the hairball has been damaged by using without appropriate diode snubber on the main contactor coil. He will be sending me a couple, but I may try to find some locally and get them installed while the controller is out for repair. part number p6ke24ca

Does anybody have a closeup picture of these installed on their contactor? I'd like to make sure I put them in the right direction. 

Second issue I was having with things cutting out when I flipped on headlights is most likely a sudden drop in voltage to the hairball during pre-charge. Made worse by the fact that the eMiata has the flip up headlights with their little motors running at the same time the headlights fire up. Solution *probably* is to put a small battery in parallel with my cheapo always on dc-dc to hold the voltage steadier.


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## major (Apr 4, 2008)

https://www.fairchildsemi.com/produ...ansient-voltage-suppressors-tvs/P6KE24CA.html

It is bidirectional.


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## dtbaker (Jan 5, 2008)

major said:


> https://www.fairchildsemi.com/produ...ansient-voltage-suppressors-tvs/P6KE24CA.html
> 
> It is bidirectional.


great, then even I can't mess it up. 

The suggestion is to install two. In parallel, or series between the +/- of the relay coil? Seems like a basic question, but I am not finding any pictures of typical installs...


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## EVfun (Mar 14, 2010)

dtbaker said:


> Second issue I was having with things cutting out when I flipped on headlights is most likely a sudden drop in voltage to the hairball during pre-charge. Made worse by the fact that the eMiata has the flip up headlights with their little motors running at the same time the headlights fire up. Solution *probably* is to put a small battery in parallel with my cheapo always on dc-dc to hold the voltage steadier.


I've had that problem too! The Hairball is very sensitive to any drops on the 12 volt supply. This thing started out as a racing controller and they didn't want any chance of not holding the contactor on hard. Headlights only draw about 9 amps once they are running, but light bulbs have a much lower resistance when starting up. So when running the pair of headlights has about 1.4 ohms of resistance. When starting up they have about 0.1 ohm of resistance. You need a good 12 volt battery so you don't have a brief sharp voltage drop when you turn them on. I don't have a 12 volt battery so cutting out when I turned on the headlights was pretty common. 

I set up a circuit with a low value ntc thermistor (about 1 ohm cold) in series with the headlights. I connected one end of a relay coil between the thermistor and headlight, the other end of that relay coil went to ground. The contacts of the relay shorted out the thermistor. When I turned the headlights on the filament resistance was so low that most of the voltage dropped across the thermistor. The relay coil didn't have enough voltage to pull in. As the headlights warmed their resistance increased and the thermistor resistance decreased. In about 1/3 of a second there was enough voltage across the relay that it pulled in and the headlights (and relay coil) got full voltage. The idea for this circuit came from Lee Hart on the old EVDL.

_I found the part I used, an Amphenol CL-11 inrush current limiter. It has 0.7 ohms of resistance cold and drops to about 0.1 ohms if it gets that hot before the relay pulls in and bypasses it. _


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## dtbaker (Jan 5, 2008)

EVfun said:


> I've had that problem too! The Hairball is very sensitive to any drops on the 12 volt supply. This thing started out as a racing controller and they didn't want any chance of not holding the contactor on hard. Headlights only draw about 9 amps once they are running, but light bulbs have a much lower resistance when starting up. So when running the pair of headlights has about 1.4 ohms of resistance. When starting up they have about 0.1 ohm of resistance. You need a good 12 volt battery so you don't have a brief sharp voltage drop when you turn them on. I don't have a 12 volt battery so cutting out when I turned on the headlights was pretty common.
> 
> I set up a circuit with a low value ntc thermistor (about 1 ohm cold) in series with the headlights. I connected one end of a relay coil between the thermistor and headlight, the other end of that relay coil went to ground. The contacts of the relay shorted out the thermistor. When I turned the headlights on the filament resistance was so low that most of the voltage dropped across the thermistor. The relay coil didn't have enough voltage to pull in. As the headlights warmed their resistance increased and the thermistor resistance decreased. In about 1/3 of a second there was enough voltage across the relay that it pulled in and the headlights (and relay coil) got full voltage. The idea for this circuit came from Lee Hart on the old EVDL.
> 
> _I found the part I used, an Amphenol CL-11 inrush current limiter. It has 0.7 ohms of resistance cold and drops to about 0.1 ohms if it gets that hot before the relay pulls in and bypasses it. _


thanks for the details on that.... my situation is exacerbated by the flip-up headlight motors coming on then the hit from cold headlights. I think I will add a little 12v battery in parallel with the dc-dc to soak up the voltage drops.

Next step appears to be sending both the hairball and the controller to Manzanita for inspection/repair. It is *most likely* just the hairball being damaged over time from running without those snubber diodes on the contactor coil, but I'd like to get both checked out.


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## dtbaker (Jan 5, 2008)

dtbaker said:


> It is 'likely' that the hairball has been damaged by using without appropriate diode snubber on the main contactor coil.
> 
> 
> Second issue I was having with things cutting out when I flipped on headlights is most likely a sudden drop in voltage to the hairball during pre-charge. Made worse by the fact that the eMiata has the flip up headlights with their little motors running at the same time the headlights fire up. Solution *probably* is to put a small battery in parallel with my cheapo always on dc-dc to hold the voltage steadier.


When I pulled things apart, it turned out that there was a snubber soldered in on the back of the main contactor coil leads. So, that wasn't it.

I don't know whether or not adding a little battery will solve my headlight killing the hairball issue, but am debating where the best place to put the battery in the system is. Or, whether there is some better way to soften the voltage drop when the headlights flip up and on.


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