Small solar project has me down a rabbit hole...

[azguy]

I'm being honest and not even kidding with that subject title.

Putting together a solar project would be easy...so I thought?! But I've come to the understanding that a person can get started doing research for solar and very quickly go down a rabbit hole with no way of coming out.

Hence, I've landed here to get help from the experts...

I started my project research with these LED lights: https://www.dhgate.com/product/mini-...arl|2737465171. From there, for my project, I was going to be using 4 of these. I chose these because I wanted to use a spotlight-type of LED: low wattage because the light need to only be subtle, waterproof because they're going to be mounted outdoors, small in size, and the backside of the housing can't be tall (puck-type I believe is what they call those LEDs).

After I chose the lights, it seemed I had to work backwards with finding batteries and solar panels. And right when I started looking into the batteries, that's when I fell into that rabbit hole and now I'm simply lost.

It turns out, there are various volts that run LEDs. If I wanted to run 9V or 12V, the lights I chose won't work. Then there's, "How long will the batteries need to power the lights?" "What physical size do the batteries need to be?" And then it goes on, "How many solar panels will you need" "What size of solar panels are needed?" Also, "What size of solar controller will be used?"

Listen, I'm a complete novice at solar and really need the help. So I'll just explain the project and the function of the lights which then leads into the solar need.

I'm building a post that will hold a sign -- picture a sign post in a yard advertising a house for sale. The post will be outdoors exposed to quite a bit of sunlight through the day (I live in Arizona). When the sun goes down, I want lights to shine down on the hanging sign that will have text information on it. The lights need not to shine all night -- I'd say they need to be on for only 4 hours after the sun goes down.

I'm limited on space -- that is all materials associated with this project will be housed inside of a wood/metal post -- so all the materials have to be in a small size: LED lights, batteries, solar panels. The LED lights can be no bigger than 1.5 inches. The batteries cannot be bigger than 4 inches in width but can be 8-10 inch in length. The solar panel(s) can be as long as 3 ft in length but the width cannot be wider than 3 inches.

Given the information above, can somebody please help me? Guide me in the right direction?

What voltage of system can or should be used? What LED lights work best with the application? Which batteries do I use? Which solar panel(s) would be ideal for the project?

[AzRoute66]

Try googling for "solar charger for 18650 batteries" and see if that refines your thought process. In my experience, one or two 18650 works fine to illuminate my flag spotlights all night long so you could easily go smaller in NiMH if you wish.

My wife buys off the shelf solar 'path lights', spot lights, flood lights, and string lights that run on NiMH or NiCd AA (at a half dozen for $8 at Big Lots or Dollar Store) for the backyard like they are cookies, and they are still shining when I head off to bed after midnite.

I think the LED lights are the crux of it. If you can visualize the perfect lighting for your signage, I am sure we can come up with a suitably sized solar battery to run it.

[SunEagle]

I agree with AzRoute66. If you want a compact solar / battery power outdoor lighting system then there are places to purchase them complete without trying to build one from parts to fit into a very small space.

Landscape or solar flood lights are easy to find and should perform as needed to fit the OP's requirements.

Otherwise to size a solar / battery system you determine the number of watt hours your load will run a day. Then determine the battery system Ah rating. Then determine the amount of panel wattage needed to replace the watt hours the load will use when the sun is not up.

[max2k]

I'm being honest and not even kidding with that subject title.

Putting together a solar project would be easy...so I thought?! But I've come to the understanding that a person can get started doing research for solar and very quickly go down a rabbit hole with no way of coming out.

Hence, I've landed here to get help from the experts...

I started my project research with these LED lights: https://www.dhgate.com/product/mini-...arl|2737465171. From there, for my project, I was going to be using 4 of these. I chose these because I wanted to use a spotlight-type of LED: low wattage because the light need to only be subtle, waterproof because they're going to be mounted outdoors, small in size, and the backside of the housing can't be tall (puck-type I believe is what they call those LEDs).

After I chose the lights, it seemed I had to work backwards with finding batteries and solar panels. And right when I started looking into the batteries, that's when I fell into that rabbit hole and now I'm simply lost.

It turns out, there are various volts that run LEDs. If I wanted to run 9V or 12V, the lights I chose won't work. Then there's, "How long will the batteries need to power the lights?" "What physical size do the batteries need to be?" And then it goes on, "How many solar panels will you need" "What size of solar panels are needed?" Also, "What size of solar controller will be used?"

Listen, I'm a complete novice at solar and really need the help. So I'll just explain the project and the function of the lights which then leads into the solar need.

I'm building a post that will hold a sign -- picture a sign post in a yard advertising a house for sale. The post will be outdoors exposed to quite a bit of sunlight through the day (I live in Arizona). When the sun goes down, I want lights to shine down on the hanging sign that will have text information on it. The lights need not to shine all night -- I'd say they need to be on for only 4 hours after the sun goes down.

I'm limited on space -- that is all materials associated with this project will be housed inside of a wood/metal post -- so all the materials have to be in a small size: LED lights, batteries, solar panels. The LED lights can be no bigger than 1.5 inches. The batteries cannot be bigger than 4 inches in width but can be 8-10 inch in length. The solar panel(s) can be as long as 3 ft in length but the width cannot be wider than 3 inches.

Given the information above, can somebody please help me? Guide me in the right direction?

What voltage of system can or should be used? What LED lights work best with the application? Which batteries do I use? Which solar panel(s) would be ideal for the project?

can you mount AGM lead batteries at the bottom of your post and run wiring inside/along with it? This could provide some room for the batteries and make your sign more stable.

For this application I think you'll be better off with 12V DC LED lights as it would allow feeding them directly from the battery without inverter. The lights from your URL are designed for normal 120-220 AC feed and would require additional component- inverter. Having 4 say 4W LED you need to supply 16W of power for 4 hrs which requires 16 x 4 = 64Wh of storage or 64Wh/12V = 5.3Ah capacity at 12V. As you don't want to discharge your battery more than 50% it requires 10-15Ah 12V AGM battery, something like this: http://www.tempestbatteries.com/html/td10-12.html
This is for reference purposes only, I have 0 experience with those batteries or any other for that matter. In terms of charge controller / panel it is rather 'challenging' due to small energy amount involved: even 50W panel for 4 hrs will produce 200Wh of energy while your demand is only 64Wh.

Suggestions above from garden lights kind of products may be much more suitable for your needs. What I described here is more 'industrial strentgh' approach which could very well be overkill here.

[azguy]

Thanks so much for the input, expertise and direction. I'll take this information and get started with the research and post again when I get further along in the project.