outside lights

[morrisbanjo]

hi all im totaly new to solar, so please help with basic talk, im not to bright.
i have just got a farm in costa rica so get 12hours good sunsine, i want to put 10 out side lights up, off the grid they need to be on for about 8hr or more,each night, i was thinking maybe as normal 40-60w house bulbs are not to bright outside maybe car head lights can be housed and used but how do i run these of solar? cars have about 55w bulbs. or spoy lights but these us a lot more power i believe. please help.

[Mike90250]

For affordable solar, incandescent lamps are NOT the ones to use. There are flood lamps made that use LED or fluorescent bulbs, that use a lot less power. Say you chose a 40W bulb.
40w x 10 hours x 10 lights = 4,000 W hours, or 4KWh
Even in sunny costa rica, the solar charging hours are less than total daylight hours, so your harvest hours are only about 6 hours, of no clouds. Battery based systems, are only about 50-60% efficient, so in the 6 hours, 8KWh of solar has to be collected. That would be an array of 1333.3Watts, or about 1.4KW of array. Using 200W panels, you would need 7 panels.
A battery bank of 8KW @ 12V would be 666.6 Ah in size, or about 7, 100Ah deep cycle batteries in parallel.
Since you are not using a lot of "peak" power, a 12V system would work fine, and there are even 12V LED & CFL bulbs, so you would not need an inverter.

However, many batteries in parallel, do not share the load well, and selecting a LARGE, off grid battery of 400A or more, will reduce the # of batteries in parallel.

Using LED's will be even less power, and your system could be smaller.

You will also need a charge controller, and fuses and meters to complete the system.

Ask again if you need help locating lights and suggested components.

If you have electrical utility power, it's usually much less expensive to run more wire, than to buy a bunch of solar panels.

[Keylan]

I think this old thread is a great way to start using the solar panels. I learned some basics today! Thanks