# Dumb Question re: Zilla Snubber Diodes



## Clipper (Jan 30, 2011)

I am installing a Zilla 1K in place of a Soliton Jr. that died.

Rather than a snubber diode to absorb the inductive "kick,"
why couldn't I just install a 12V 30A relay to completely isolate it?

Surely the inductive kick of a small relay is much less than that of a main contactor solenoid...??!! 

I suppose I could even use a solid state relay...


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## EVfun (Mar 14, 2010)

The relay coil will also have a kick. When a coil is switched off it will produce quite a high voltage if there is no place to dump the stored magnetic energy. Even a 30 amp cube relay will generate enough voltage to give you a little shock. Without the TVS the voltage generated will fry parts designed for a max of 35 or 50 volts. A nice bi-directional TVS should have come with your Zilla -- it is absolutely important you use it . They are only about $1 part at Mouser of Digikey (1.5KE24) and the Hairball will be damaged if you don't use it. A regular diode should never be used in place of a TVS as they greatly slow down the contactor opening speed.


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## MattsAwesomeStuff (Aug 10, 2017)

I don't think you're worried about the inductive kick of the solenoid coil...


You're worried about the inductive kick of hundreds of amps flowing through the motor, which is an inductor.


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## Zappo (Sep 1, 2011)

No, actually EVFUN is correct. The only problem I ever had with my Zilla was when I damaged the output of the hairball. I thought I would be okay driving a small ice cube relay as an isolation relay. Without the diode, I fried the output. Lesson learned. I had the hairball repaired, installed the diode and ran trouble free for over 30,000 miles.


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