another first post with questions

System

I work for a school District and we got our hands on 6 ,12 volt 60 watt pv panels and would like to use one of them to light up a sign in front of one of the schools the lights would be inside the sign and would only have to be on for 5 hours a night and if there are 3 days of clouds and the sign does not come on it would be no big deal.
I was thinking of using one panel thru a controler to a 94 amp hour agm battery and then to the lights the problem is what kind of lights?
The sign is outside and the winters here are cold so ffloursent might not work to well unless I use a sign ballest but havent found one for use with 12 volt
the sign is four feet wide and three feet high.
S what do you think led ? cfl? 12 v incadecent ? what would the maxium wattage I should use for the bulbs Thanks Matt::D

mike95490

Re: another first post with questions

mattt wrote: »

S what do you think led ? cfl? 12 v incadecent ?

what would the maxium wattage I should use for the bulbs Thanks Matt::D

You only want to use 1 panel ?

The most efficient light so far, has been the LED specialty bulbs. That would solve the maintenance issues that the others have with replaceing bulbs and ballasts (even mercury and sodium lamps burn out after a year or so)
The only draw back is initial cost for outdoor sealed unit.

How bright do you want the sign ?

System2

Re: another first post with questions

do you think I would more than one 60 watt panel to light 3 or 4 13 watt cfls for 5 hours
also the lights would be inside the sign not aimed at it from the ground

BB.

Re: another first post with questions

Yes, by the time you add up all of the losses, changes in season, etc..., it would be too much to expect from a single 60 watt solar panel...

For a start, use this website to see how much power you can generate:

using 60 watts (smallest panel allowed is 1kW--so the numbers are 60kW--but read results as watts and watt*hours vs kW and kWhr), 54% efficiency, Philadelphia, you get about 2,500 to 4,600 Watt*hours per month, or (x/30) 83 to 150 watt*hours per day...

Your load is 4 lights x 13 watts/light x 5 hours per day = 260 watt*hours per day...

So, even in full summer sun, you would need almost 2x60 watt panels. During the winter you would need 3+ panels for the winter.

You have to "believe" my 54% derating number (based on STC panel derating * charge controller eff * battery eff * inverter eff)--and your losses may even be higher with a small system.

-Bill

mike95490

Re: another first post with questions

for a 4x3 sign, I'd look into using long tube fluorescent lamps, not CFL's

Here's an example:
http://store.solar-electric.com/tl-141.html
Thin Lite #141 Strip Light 12 Volt DC

Say you have 4 of these 8W Fixtures, and one of the Morningstar Sunlight Solar Lighting Controllers, (has a built in timer) should do you pretty good.
http://store.solar-electric.com/sunsolligcon1.html

System2

Re: another first post with questions

mike90045 wrote: »

for a 4x3 sign, I'd look into using long tube fluorescent lamps, not CFL's

Here's an example:
http://store.solar-electric.com/tl-141.html
Thin Lite #141 Strip Light 12 Volt DC

Say you have 4 of these 8W Fixtures, and one of the Morningstar Sunlight Solar Lighting Controllers, (has a built in timer) should do you pretty good.
http://store.solar-electric.com/sunsolligcon1.html

Yeah I was tihnking same. CFL's I assume would run 120v meaning use of an inverter & 10x amperage draw. You could accomplish with the 12v strip Mike mentions.

That lighting controller is cool, uses your solar panels as a dusk/dawn sensor - good idea.