quick question please help

[papa john]

ok quick question, i was debating about getting a solar panel to like mess around with, so i can get a better understanding of it and whatnot, that said one thing i was worried about is when you have multiple solar panels hooked up to some batteries is it possible for the power to go back through from the batteries to the solar panel at night? (when theirs no power being made)

now i read somewhere that theirs something you put inbetween them that stops this but id just like to make shur,

and on that note does anyone know a good place to find some notes on this type of stuff? so i know what to do and what not to do. simply put a clean cut way to see how to set up one of these systems and the safety hazards.

[BeenzMeenzWind]

Yeah, just use a blocking diode. It will allow the current to flow from the panels to your batteries when they are producing power but doesn't allow current flow the other way when they're not. Some of the other guys should be able to tell you what the best stuff to use is based on their practical experience. I'm just playing with RE at the moment, still firmly attached to the grid. lol

[drdongle]

Most if not all panels include a blocking diode in the terminal box.

[ghurd]

A lot of good information here,

http://www.solar-electric.com/

Most or at least many small PVs, like 10W and less, have the blocking diode built in.

Most PVs over 15W do not.

[joelhacker]

I think the reason for that might be that the larger

panels allow for themnselves to be connected in series

and would eliminate the compounding effect of voltage

drops by multiple blocking diodes...

Also, try to find a shottky diode...lower forward

voltage drop :-)

[papa john]

so basicly, any system would have this diode that prevents you from getting shocked when you disconnect the solar panels? so i dont need special protection like rubber gloves for disconnecting these things? and what about connecting them during the day? is their like an off switch so you dont get shocked while connecting them?

and thanks for all info guys and gals?

[ghurd]

I believe larger PVs will be used with a controller, and blocking diodes will just be a redundant waste of voltage.

G-

[ghurd]

A 12v system will be about 20V open.  It will give you a tickle, especially if you are sweating.

A 24V system will be about 40V open, and that just hurts!

They will not bite if you don't touch 2 wires at once.

I put a fuse between the PV and controller.

Pull the fuse, disconnect the battery, and the whole system is dead.

Except for the PV wires.

G-