# Diodes in solar panels



## john10001 (Mar 20, 2013)

What are the most common diode specs that are used in solar panels? 

Does one type of diode fit all, and do you keep spares just in case?


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## budgetprepp-n (Apr 7, 2013)

I didn't know that all solar panels have the diode built in. 
I thought that the controller took care of any "feed back"


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## pheniox17 (Dec 12, 2013)

if its ac to dc power , its generically reversed biased zennor diodes 

but solar maybe a little different, if output is DC then you will have a very similar setup to converting ac to DC as a protection


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## Montana Rancher (Mar 4, 2013)

john10001 said:


> What are the most common diode specs that are used in solar panels?
> 
> Does one type of diode fit all, and do you keep spares just in case?


I agree with budetprepp-n

I have a 4k solar system powering about half my house and I don't even know about diodes.

I have a really high tech charge controller, which takes most of the guesswork out of a solar system, send me a PM about specific questions
Dean


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## HuntingHawk (Dec 16, 2012)

Most solar panels have the blocking diode built in. Its purpose is to only allow the voltage to travel in one direction which is away from the panel. If there is a small box in a corner of the underside of the solar panel where the connecting wires come from that is where the blocking diode is.


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## john10001 (Mar 20, 2013)

HuntingHawk said:


> Most solar panels have the blocking diode built in. Its purpose is to only allow the voltage to travel in one direction which is away from the panel. If there is a small box in a corner of the underside of the solar panel where the connecting wires come from that is where the blocking diode is.


Thanks! Do you know what type of blocking diode would be used in a solar panel?

I understand that the majority of solar panels have blocking diodes including all panels over 20w in size.

I am thinking of getting spare blocking diodes in case they are ever needed e.g. due to solar flare and EMP generated by other means.

It is not worth not having something that may be extremely cheap to buy now that may be needed after a SHTF situation.


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## budgetprepp-n (Apr 7, 2013)

I thought the "one way" diode was built in the controller. I don't know for sure, But I would like to 
I think I red that when I bought the controller 


question, Is that the correct way to spell RED when used like that? No really is it?


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## HuntingHawk (Dec 16, 2012)

Blocking and By-Pass Diodes Used in Solar Panels


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## bad (Feb 22, 2014)

If you want a simple blocking diode, you need to consider the power dissipation ability of the solar panel. So a panel that maxes at 1 amp, I would probably use a rating of at least 3-6amps and at least 50 Volts for reliability. If you choose a bigger rating nothing will be changed.


My solar cells came with a distribution module but I am running one of my panels solo directly connected to a battery to keep my electric fence going. My module wouldn't take being outside. I haven't used a diode in series and not noticed any ill effects.


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