how to connect sharp solar panels

[blueEnergy group]

I have 4 Sharp NE-80EJE Solar panels wich I want to connect in parallel.

I thought it would be easy, but there is a junction box with two positive terminals and two negative terminals with diodes drawings upon.

I don't understand if those diodes are bypass or blocking diodes, and neither how they are connected internally with the positive and negative of the panel.

I couldn't find any documentation on the internet on those panels to help me.

Anybody has experience with those panels?

Should I just try to make a circuit that don't use the diodes?

Anne-Claire

[tecker]

Just looking at the cut Sheet i can see your dilemma . meter it out to be sure but I think those are parallel an for in and out convenience.

[blueEnergy group]

What do you mean exactly by parallel? parallel to what exactly?

I thought to meter it yes. Precisely I wondered if I only could measure the current when the panels are connected to the charge controler and batteries, or if I can measure directly the short circuit current when the panels are connected just between themselves? It might be more practical but I was affraid shortcircuiting the panels would damage those. But as shortcircuit current is always specified, I suppose you can no?

Thanks you very much for the help

Anne-Claire

[ghurd]

Anne-Claire,

Use NONE of the diodes that came with the panels.

Each panel is really a 12V module.  Each 6V PV is in series with another 6V PV, to make a 12V module.

A bypass diode is across each 6V PV.

In a 12V system they are not needed and could cause problems.  I would suggest simply cutting them completely out.

It is that simple.

The main power points in the module will be about 20V open circuit.

Ignore the rest of the connections, except to make sure they are tight.

I know that makes no sense,

so cut out ALL the diodes,

and use the connections that make ~20V open circuit.

Place those +20V leads to the charge controller, in parallel.

Cut out the diodes, find the ~20V terminals, use them.

G-

[jimjjnn]

Short-circuiting your panels won't hurt them. Just be sure you aren't connected to batteries tho

[blueEnergy group]

ok, thank you very much

just one precision: if I don't cut the diodes, the possible problems are if the diode burn and short circuit the pannel, no?

the panels are not mine, so maybe I'll avoid destructive operations...unless it's much better without the diodes.

Anne-Claire

[blueEnergy group]

one more question: does the open-circuit voltage depend on the weather or only the intensity does? (I'm in Nicaragua, it's the rain season, and we have clouds 24h/24 those days...) - anyway the main points of the panels are those who got the greater difference of potential no? to make sure I can identify those correctly

[snowcrow]

Hi Anne, this is what the wiring should look like. The diodes serve as both bypass and blocking diodes, depending on the wire connection. In your case, 12v parallel connection, they act as blocking diodes, preventing back flow current if the panel becomes shaded. PV panels without these diodes will draw down the voltage of all unshaded panels in the array. The diodes thus help to keep a continues voltage output from the PV array even with some panels shaded.

Blessings, Snow Crow

[ghurd]

Yes, the bypass diodes can burn and short that half of the panel.  It is not common, but it does happen.

Often, the diodes can be removed from the circuit by removing one screw, bending the diode out of the way and replacing the screw.  The diodes will be intact if the owner wants to replace them later.

They serve no purpose in a 12V system.

The open circuit voltage is related to how bright the sun is at the time.  I often see 18 to 22V.  The panel is in 2 halves, each half making about 10V, together they make 20V  

It is better to have no blocking diode.  The charge controller does that.

G

[blueEnergy group]

The pannels arec now connected and seem to work great. Finally measuring the voltage I could check that the diodes are in parallel to two 6V modules connected in series in the pannel.

Thank you very much for your help!

Anne-Claire