Outdoor night light on big pole... Wanting to run it off of solar - Questions!

[blakeaf96]

I have a question... I have an outdoor night light that has an LED bulb installed. This is one of those ~15 foot tall lights that automatically comes on when it gets dark and cuts off when it gets daylight. Anyways, I was thinking about buying a simple $200 kit which contains (1) - 100 watt solar panel and a charge controller. I know I'll have to buy patch cables, battery, etc BUT the only question I have is 1) Will this be plenty enough to run 1 night light? I have no intentions of running anything else off of it so no need for a power inverter, etc.

So will that kit that I'm wanting to buy run that 1 night light where it'll stay on all night long and not cut off from lack of energy? Thanks for the help!!!!!!

[blakeaf96]

Here is the info off of the light itself...

150w / 55v / HPS / s55 / lamp
120v / Input / 60 Hz
4.60 Amps

[blakeaf96]

And I'm in an area that gets 6 sun hours per day

[blakeaf96]

I'm thinking about buying this light to replace what I'm currently using because after further inspection, this light is worn out.... So I think I'm going to buy this one.. So what will I need to be able to run this light roughly 8-10 hours per night?

https://www.amazon.com/gp/product/B077RVNFKM/ref=ox_sc_act_title_2?smid=A3NG14OPL35XMM&psc=1

[SunEagle]

The simple math for your needs is taking the light 's wattage and multiplying it by the number of hours you want it lit.

So for say 8 hours you will need 1200 watt hours (150w x 8hr = 1200wh). Then divide that 1200wh by 12volt which comes to 100ah. Then multiply that value by 5 (that keeps the battery to no more than a 20% daily discharge) which comes to 500Ah battery. For proper charging you need a C/10 charge rate or 50amps. To get that type of charging you will need 50a x 12v = 600w or at least 6 of those 100watt panels. and a quality 60amp MPPT type CC.

Now with loses you will probably need more than 600w but that is a place to start.

[blakeaf96]

Thank you SunEagle - Much appreciated... So if I buy a NEW light which would be a 60w LED, I would do the same math based on 60w instead of the 150w, correct?

[SunEagle]

Thank you SunEagle - Much appreciated... So if I buy a NEW light which would be a 60w LED, I would do the same math based on 60w instead of the 150w, correct?

Pretty much. The math stays the same but the amount of watt hours will determine your battery size and panel wattage. You can use a smaller battery but if you discharge it more than 20% each day you end up cutting the lifespan and number of "cycles" it can provide you.

[blakeaf96]

Thank you! I think I have it narrowed down...

Light I'm buying

https://www.amazon.com/Bobcat-Photocell-Included-Incandescent-Equivalent/dp/B074HZ3G57/ref=sr_1_6?keywords=60w+led+barn+light&qid=1567361317&s=gateway&sr=8-6

Solar Kit I'm buying:

https://www.amazon.com/Renogy-Solar-Premium-Monocrystalline-Controller/dp/B07CTG8YR4/ref=sr_1_3?keywords=300+watt+solar+panel&qid=1567361231&s=gateway&sr=8-3

Would that kit be a good start? I know I'll have to get the batteries, etc.. But as far as the kit to run that light.. Does that look like I have the correct stuff ready to buy? I want to make sure before I place the order. Of course I can always add another solar panel if I need to.. Even if I have to run it for 6 hours per night, that's also fine..

I really, really appreciate your help!!! THANK YOU AGAIN!!! =) =)

[blakeaf96]

So if I buy an outside LED 60w night light (if my math is correct), I would be looking at roughly (3) - 100 watt solar panels.. Does that sound about right? I really appreciate you helping! I'm about ready to buy and want to make sure I get the right amount of panels. Even if I have to cut back on the number of hours it runs to 6-7 to be able to make 3 panels work...

[SunEagle]

So if I buy an outside LED 60w night light (if my math is correct), I would be looking at roughly (3) - 100 watt solar panels.. Does that sound about right? I really appreciate you helping! I'm about ready to buy and want to make sure I get the right amount of panels. Even if I have to cut back on the number of hours it runs to 6-7 to be able to make 3 panels work...

That should work provide you use a 250Ah battery. You can probably find a 6V 225Ah battery and if you get 2 of them and wire in series you get a 12V 225Ah system. That should work if you don't over discharge it more than 25% each night.

[foo1bar]

So will that kit that I'm wanting to buy run that 1 night light where it'll stay on all night long and not cut off from lack of energy? Thanks for the help!!!!!!

So you already have power out to the pole.

I think it's likely that the cost of the battery (replaced every X years) and the charge controller/inverter and solar panel are going to far outweigh the costs of the energy from the power company. So probably not a real benefit if you're looking at costs over 10+ year timeframe.

If you're looking at it from an environment perspective, you should ask yourself how batteries you're consuming compare to the power you're consuming. (if you have nuclear power being provided for your area, IMO that's better for environment than the batteries by far) Even if it's coal IMO it's debatable which is better from environmental view.

JMHO - but I'd go with more energy efficient fixture/bulb.
And separately look at doing grid tie solar.

[Mike90250]

Here is the info off of the light itself...

150w / 55v / HPS / s55 / lamp
120v / Input / 60 Hz
4.60 Amps

That's not an LED bulb, it's a high pressure sodium (HPS S55 bulb) And you need an inverter !! 120V 60Hz

So if you want LED , here's a way. ( 5A flood assy)
3, 20W floods https://www.wiredco.com/20_Watt_12V_...lood20wdc1.htm

20A solar lighting controller & 20A PWM charge controller https://www.morningstarcorp.com/products/sunlight/

And whatever batteries and panels you need to support it all.

The LED's would be less bright than the 16,000 lumen HPS bulb. (but LED's are more directional, and the HPS bulb looses some in the reflectors.)

But simply getting a photocell LED fixture would be both more economical and green. (unless you really need the batteries for zombie control)

[khanh dam]

Glad Mike finally pointed out the obvious. But let's remember high school physics. The inverse square law states that Brightness doubles according to the square of the distance. So instead of using a 60W led 12v bulb at 16 feet , you could use a 15W bulb at 8 feet and have the same brightness.

There fore you are better off with a few smaller watt bulbs closer to the ground.

in fact you are best off not even trying to DIY it. Just go to lowes or home depot they have led lights with mini solar panels and SLA batteries for less than $100 with motion detection.

maybe you have some special need to have the light on for the ENTIER NIGHT? most people are fine with having the light on for 10 minutes while they are in that area.

I dont' know seems like using a sledge hammer to put a push pin in a corkboard.

[RJ68]

Call me crazy, but by the time you buy all the stuff needed to light the pole, ($900-$1200) seems like using the grid would be a better way to go. Have you priced batteries and an inverter yet?
I would be looking to grid tie the solar and offset power usage during the day and eliminating the batteries.

Is there a special reason you want to light the pole with solar?