What's Needed For Decorative Streetlamp

[Gtshadow]

I am looking into converting a large decorative street lamp in front of my house to solar. It is one of those with the 12 inch white globes on top. It has 5 lights and I currently use 14 watt cfl bulbs in each. I would like to keep the bulbs the same, unless there is a large benifit in using led. I would like to run this dusk to dawn. Since i know very little about solar, I would like to know what kind of solar panel i would need, how large, what kind of battery or batteries, inverters, etc... Basically everything you always wanted to know, but were afraid to ask. I have basic household wiring skills but dont know much about converting DC to AC. Any help is appreciated!

[Mike90250]

winter, dusk to dawn = 13 hours 5*14=70watts * 13 hrs = 910watt hours. That's about 20 cents a night in winter, maybe 15 cents a night summer. $73 a year worst case utility bill.

a "12v marine battery @ 85ah has a total of 696wh, only half of which are useable. So now, just the battery is at least two 6V 200ah golf cart batteries. Figure about $300 for that, replace them every 2-3 years

Can you tolerate the lamp being OFF if you have a couple cloudy days that provide no solar charge ? If so, you can use a smaller PV panel array. The 200ah battery would like to see a 20A charge rate at 12V, so that's 240 watts delivered. Most panels only reliably produce 80% of nameplate, so you need at least 300w of PV panels. There's another $350, plus mounting pole and hardware maybe $250 ? And another $200 for a MPPT charge controller, and misc fuses, terminals and cables.

I'd just stick with the grid. Maybe replace the CFL's with LED lights, might take the wattage down to 10W each. But LED bulbs in a sealed housing with no cooling air may fail sooner than the CFL mercury bombs.

[Gtshadow]

winter, dusk to dawn = 13 hours 5*14=70watts * 13 hrs = 910watt hours. That's about 20 cents a night in winter, maybe 15 cents a night summer. $73 a year worst case utility bill.

a "12v marine battery @ 85ah has a total of 696wh, only half of which are useable. So now, just the battery is at least two 6V 200ah golf cart batteries. Figure about $300 for that, replace them every 2-3 years

Can you tolerate the lamp being OFF if you have a couple cloudy days that provide no solar charge ? If so, you can use a smaller PV panel array. The 200ah battery would like to see a 20A charge rate at 12V, so that's 240 watts delivered. Most panels only reliably produce 80% of nameplate, so you need at least 300w of PV panels. There's another $350, plus mounting pole and hardware maybe $250 ? And another $200 for a MPPT charge controller, and misc fuses, terminals and cables.

I'd just stick with the grid. Maybe replace the CFL's with LED lights, might take the wattage down to 10W each. But LED bulbs in a sealed housing with no cooling air may fail sooner than the CFL mercury bombs.

Wow! That is a lot more expensive than I ever thought in my worst nightmare. I can see why solar is not more common. Thanks a lot for the info. Very detailed. I guess that I will stick with the grid unless prices go down.