Solar panel reverse current

[dehler25]

I am hardly electronically challenged, but I did want to verify before taking action! Is there any other reason for blocking diodes in solar panels other than reverse current? If the controller has reverse current protection can I strip all diodes out of the terminal connections. I ask because I have seen components that had ulterior motives for their existence. I am connecting three panels and ridding myself of unnecessary voltage drops would be a benefit, six diodes @ .7 volts is 4.2V gained.

 

[LeeandRick]

Works fine if the panels never see a spec of shade.

 

[capta]

Since most solar panels I'm familiar with produce 18 volts DC or more (if going w/24 volt panels), why would you care about the voltage drop? The controller is designed to regulate the input voltage to a nominal 12 volts anyway.

 

[dehler25]

Thats why the controller has to have internal blocking, if it didn't there would be no question.

 

[Ron20324]

Thats why the controller has to have internal blocking, if it didn't there would be no question.

From the other end, that's why solar panels have built-in diodes- to idiot-proof the panel.

 

[Rick D]

https://forums.sailboatowners.com/index.php?threads/blocking-diodes.188984/

 

[Maine Sail]

Your panel has bypass diodes not blocking diodes. You do not want to rip out bypass diodes. The controller will prevent back feed at night....

 

[dehler25]

Thanks for the link, I guess my concern revolved around the fact that we are typically talking small numbers i.e. less than twenty volts for a parallel connect so dropping four would seem to have an impact. I am just now building the solar system, I built the supports above the davits and the shortest is ten feet wide. I only have three 70 watt panels at present but wanted to be able to grow the farm in the future without a rebuild. I also factored in placement for antennas or what ever needs a mount. They are far enough out that shading would seem to be a nonissue. I am considering a series connect which would also increase the voltage having even less impact. Sometimes simple things get confusing!

 

[dehler25]

There are three diodes in the connect panel one for 6v and two for the 12v connect, the panels are not new and I replaced one on a panel that tested open. I assumed they existed as blocking as they are high current devices.

 

[Benny17441]

I think it all works out in the wash. Diodes voltage drop or power robbing shaded panels?

 

[Maine Sail]

I think it all works out in the wash. Diodes voltage drop or power robbing shaded panels?

Bypass diodes only bypass when the panel is shaded thus bypassing cells/strings that are shaded...

Best to read the explanation here: AltE Bypass & Blocking Diodes

 

[dehler25]

The diodes I am referring to are in the connection box and there are only two for the 21 volt circuit. I don not remember the part number but hey are high current connecting between the pos and neg contacts

 

[dehler25]

The link explained why I had it wrong I didn't realize blocking typically preceded controllers and was outdated good that I didnt get impulsive. Now I know.

 

[njlarry]

Bypass diodes only bypass when the panel is shaded thus bypassing cells/strings that are shaded...

Best to read the explanation here: AltE Bypass & Blocking Diodes

Thank you yet again Maine Sail. The link and video where great. Appreciate your help. It lifts the forum up several notches!