Solar Sign Lighting

[h2yoho]

Hi. I need a solar setup for an 8'x4' sign. I'm thinking in lines of 2, or possibly three of these for light source. LED Flood Light (160 LED's) 8.5w White IP65
It will involve using 12 to 240V invertor, a dawn to dusk photocell and a time switch. The lighting source will run from dusk till 23.00, but the timeswitch, photocell & inverter will need to be on constant power, so battery & solar panel charger will need to be of enough capacity to cover this.
Can anybody give me an idea as to what size of panel & deep cycle battery I would need, please?

 

[desertbootz]

1. What are the power losses of yr invertor going to be?
2. What are the power requirements of the sun-switch and timer?
3. How much sun do you get as a worst case, eg, a murky week in winter?
4. How much space do you have for panels?
5. How much space do you have for batteries and can it take the weight?
6. How much do you want to spend?

I'm thinking why go DC-AC-DC? Could the luminaire be adapted to take direct from the battery? If it's a 240V fitting then presumably it has a transformer and rectifier built inbefore feeding the LED's. Get rid of that and direct drive them and you get rid of a lot of gubbins, cost and power losses?

Assuming you can then yr after about 30W/h for 3 fittingsr. Assuming the LED are 12V then yr looking at roughly 3A/hr. Worst day of the year lets say lights on at 16H00 so you'll need 21A/hr. Getting that out of a bettery isn't too much of a problem but it's got to be day after day.

A half decent panel (1000 x 400mm) will give you about 80W peak so reckon on a half to a quarter of that in low light and on the worst day you can expect only about 7 hrs daylight so one panel might give you 140W or something like equiv. <10A/hr. That's not gonna keep the lamps burning unless you've got lots of battery capacity. The alternative is of course more panles. The reality is you'll need both!

That's all of the top of my head whilst I ate a turkey sandwich. If you have a look on the net you'll find specs for panels and batteries giving performance curves and the like, however, my advice is treat all figures with a large pinch of salt :O)

 

[h2yoho]

Hiya desertbootz. Thanks for your reply, and sorry for not getting back sooner. I did read your reply and have done some research. To do a decent job would cost around the £2,000 mark. I gave my customer the rundown, but it was thrown out the window on price. Not suprised. lol
Thanks again for your help, though.