Which zener diode

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Anton
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Which zener diode

Post by Anton » Thu Mar 22, 2018 9:49 pm

Hey, ppls. A friend of mine wants to put a pair of relays into his Toyota to switch his high power headlights. Recently the current draw (2x 60w bulbs, so 10a total load) melted the switch inside the indicator stalk, after which no headlights (although thankfully no fire).

I'm thinking a zenier diode would be good, to stop high currents flowing back through the circuit and maybe even into his ECU, but what voltage? Would 15v be ok, or should I go for 17v? I remember reading somewhere that +3v is a good rule of thumb, meaning that a 17 would be more appropriate, but my memory might be shonky. Or shcottky... :brows:
1985 SJ413VX (SJ50V) with SPOA, rear disc brakes, 31x10.5R15 Kaiman Malatesta tyres, an MOT and a lot left to do!

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Robert.m
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Re: Which zener diode

Post by Robert.m » Sun Mar 25, 2018 9:02 pm

I thought wiring the HP lights through a relay would be sufficient to avoid melting anything.

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Anton
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Re: Which zener diode

Post by Anton » Mon Mar 26, 2018 12:29 am

It is. I'm not worried about the lights melting anything once the relays are in, I'm worried about the voltage spikes that relays cause when their electromagnetic field collapses.
1985 SJ413VX (SJ50V) with SPOA, rear disc brakes, 31x10.5R15 Kaiman Malatesta tyres, an MOT and a lot left to do!

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acestu
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Re: Which zener diode

Post by acestu » Tue Oct 29, 2019 9:14 pm

Hi,

Just get a DC relay and base from city electrical it will allready have a snub diode on it, or if you allready have an AC relay what i normally use is a couple of 1N4001 rectifier diodes in parralel wired across the terminals, make sure the cathodes of the diodes (painted line end) are the same way round and on the posotive terminal, hope this helps

Stuart

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Anton
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Re: Which zener diode

Post by Anton » Wed Oct 30, 2019 12:09 am

He bought a pre-wired kit for this about a year and a half ago. Was cheaper than the individual components.
1985 SJ413VX (SJ50V) with SPOA, rear disc brakes, 31x10.5R15 Kaiman Malatesta tyres, an MOT and a lot left to do!

My: Build thread To-do list Pay and Play map

acestu
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Re: Which zener diode

Post by acestu » Wed Oct 30, 2019 9:15 pm

Hi,

I replied to it and then realized how long ago it was

Stuart

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