solar project prep work

[WayanLam]

hi all,

so here is my first post!

so i am in the process of building up a little solar array for my soon to be home that is under construction.

i live in Bali, a small island in Indonesia (south of the equator), and quite a favorite holiday destination for many ppl, above all ozzies.

anyhow, my plan is to build up four 160~w solar panels from noncrystalline cells that i am buying (DIY!!)

watched and read a lot about this in the past couple weeks, and i have also attended a PV solar course several years ago, for which i have some useless piece of paper saying that i have learnt the basict of PV systems, ha ha... but since that was numerous years ago, and just a theoretical course it wont be of too much help, so now comes the fun part... the practical test!

im ordering 200 cells, rated at 4.5w each. IF i dont break too many i could make 5 panels, but lets see... ill be happy to get away with 4 to start with, but if im lucky... i could get five (36 cells per panel).

i have started to look into the application of bypass diodes within solar panels to help prevent cell damage during partial coverage.

i have ordered this junction box:



and am wondering... how is it supposed to be wired? it has four connection points into the junction, and two leads coming out to hook up to my other panels/charge controller (+) & (-).

im rather new to electronics, so im trying to absorb a lot of info, and so far i haven't quite grasped how it should wired up for this junction box.

i am planning on doing four rows of nine cells. but im open to other configurations if it works better with the way i should connect the cells up to this junction box.

thank and hope someone can shed some light on this for me

cheers!

[WayanLam]

so i might have found the answer to my own question after watching this video:

http://youtu.be/S6dqf_NCr9I

if i am not mistaken, i need to connect the bus wires in the following manner to create the two circuits within the one panel:



feel free to corect me if im wrong though!


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edit~

this brings up another question actually...

should i be adding a diode here:



where i drew it, so that no power can leech back into the last positive string of cells? or would that be protected from the other junction box already?... im not really sure... lol

[SeanB]

Correct in the wiring, and you do not need any extra diode there, as the charge controller will have one in it. The junction already has bypass diodes for each panel and for the whole unit, so no need to add any.

Just remember to spray inside the box after assembly with some silicone spray grease before placing the cover on, so that you do not get corrosion from salt spray ingress into it.