# 12 volt solar panels and LED lighting advice please

#### Tonyr1084

Joined Sep 24, 2015
6,599
On another thread solar power is being discussed. This makes me think of something I might want to do. I have an addition on top of my garage along with a large deck. Solar lighting would be great up there, on the deck and along the front of the addition. Solar seems like a good choice, but I can't find anything close to what I want to do.

Here's my thinking (feel free to offer other advice as well)
A single solar panel on the roof of some decent wattage, probably 12 volts.
A string of LED lights, possibly rope lights, possibly spot lights - whatever - no specific decision has been made on what's desired.
A 12 volt rechargeable battery, could be SLA, could be Li-Ion type, again, no decision has been made as yet.
Some sort of charge control circuitry to charge the battery.
Some sort of LDO (Low Drop Out) circuit to prevent draining the battery excessively
Light sensing to switch solar lights on at dusk (or possibly on a timer) and off at dawn (or the timer)

I've looked a few places on line but not exhaustively. I figure quite possibly someone here already knows of either an entire setup OR may have parts of that setup. Coupled with other advice, I could put together an entire system. Space doesn't seem like it will be much of a concern. I live in the northern latitudes, 41.130034 Latitude specifically. Roof slope 4:12 pitch (approx. 19.5˚ angle)

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#### Audioguru again

Joined Oct 21, 2019
4,104
First you need to find how much power you need.
Buy one string of LEDs and a wall-wart to see the brightness. One string does not make much light so maybe you need 10 or 20 strings. Then a calculation will show that you probably need an enormous and expensive solar panel and battery.

#### Tonyr1084

Joined Sep 24, 2015
6,599
I have looked at a 100W panel at a cost around $140. As for lighting; I have yet to come to a consensus. I may just go with those garden / walkway lights. It's cheaper and I don't have to run wiring, although I'm not opposed to wires. As for a battery, I have a couple spare car batteries I could throw down and charge. Let the panel keep it charged and the dark sensor turns the lights on. Yes - I said "Dark Sensor". I know, I know; no such thing. Well maybe not. Scientists and Cosmologists have discovered "Dark Matter", so maybe there IS such a thing. I guess I'm looking for a sensor that turns the lights OFF when there's sufficient light. This is one I saw and might consider. #### Audioguru again Joined Oct 21, 2019 4,104 Amazon says the 100W solar panel kit produces "Voltage at Pmax: 23V. Current at Pmax: 4.3A" Then how can it produce what it says is 12V at 20A? Solar garden lights do not light up anything. Each light is 3V at 15mA= 0.045W. 1000 of them would light a small deck. #### Reloadron Joined Jan 15, 2015 6,317 Tony, I guess it depends on what you want to invest for an experiment. There are solar panel kits available which can greatly simplify things. The link is merely an example but nice thing about a kit is it includes all the basic essential items needed to get started. Keep in mind you need a good southern exposure where you mount the panels. Also keep in mind solar panel output is based on direct sunlight so overcast or cloudy days they will not produce rated outputs. Then of course your first step is to determine how much power you need, as was mentioned, allowing for some overhead, Personally if I were to pursue something like this I would start by looking at various LED lighting schemes and find what will work for your application. Once you know your power requirements, allowing some overhead I would move from there. Really depends on how much light you want. Ron Thread Starter #### Tonyr1084 Joined Sep 24, 2015 6,599 Well, gentlemen (and or ladies); I'm not looking to light up the area with a flood of light. Some ambiance would be nice, and perhaps a set of lights along the driveway for evening backing in. The wife doesn't back up well in daylight. At night she doesn't even try. "Honey - park my car please?" Otherwise she'll knock the fence over or crush her garden. No, I'm not down on her, she's just not good at navigating in reverse. Anyway, for driveway lights - I could throw a 12V transformer and some very low wattage LED's to act as a reference guide when backing up. We back in because there are children that play in our street. Pulling out forward makes it a lot easier to not hit a child. Backing in is safe enough because when you pull up you know if there are children around. What was that I read on another thread? Someone's 10KW solar is only producing 800W due to overcast Skys. Well, even garden lights would have a hard time charging up under those conditions. And if lights don't light - no big deal. This project is only in the dream state. I'm dreaming of a light Christmas? IDK! #### Externet Joined Nov 29, 2005 1,732 Option to consider... These and alike with replaceable 18650 cell built-in are surprisingly good, when extra-waterproofed and spiderproofed before installing. Perhaps many of them will make you happy. Seen them at about$13 each, and if one fails until you have fun fixing it, you will still have others working .

----> https://www.aliexpress.com/item/32873926775.html

Edited- added ----> https://www.ebay.com/itm/202878799628?hash=item2f3c84cf0c:g:8w4AAOSwYSZfcaIA

Ron

#### MisterBill2

Joined Jan 23, 2018
10,502
I have visions of an aircraft runway and if you really do it right they will see your driveway from the ISS (International Space Station). Seriously for what you are wanting to do I wouldn't worry too much about solar panels. You can just run with a 12 VDC power supply and even with 20 of what you linked to you are only looking at 2.5 Amps. I guess if you wanted to get really cool about it you could run them like a garage door opener and light. Door opens and light is on about 15 min. This way they are only on a short period when coming and going. A 12 VDC 5.0 amp power supply runs under \$15.00 USD. You can even have a battery backup with a few modifications to the garage door opener scheme. Anyway, after the table saw is in place and cabinetry done. Thanks for reminding me, I have been wanting to replace my old table saw.

Ron
I can make you a great deal on a Craftsman Radial Arm saw. available now.

Joined Jan 15, 2015
6,317
I can make you a great deal on a Craftsman Radial Arm saw. available now.
Thanks but I wanted another table saw but a radial arm saw is also a real nice to have. In several months planning on a whole lot of flooring going down, once the ceilings are done.

Ron

#### Tonyr1084

Joined Sep 24, 2015
6,599
I have an older Genie opener that has failed. I've been trying to figure out why it will move a quarter inch then stop no matter what I do. Up or Down, it barely moves. I should check the optical sensor stuck to the end of the motor shaft. That may have died. Have tested the cable and it shows good, so - - - . But I'll try again and see what happens, if it turns the light circuit on I can use that to connect a transformer. {suddenly Tony has an epiphany} I have many of those low power bricks saved from old satellite receivers and modems that generally run 2 amps to as much as 5 amps. Never mind messing with a transformer and rectifying circuitry - it's ready made!

I've ordered the 10 white side marker lights, they'll be here Tuesday. I also have a spool of 18/2 solid conductor that can be run along the fence. Butt splices every 8 feet (fence posts). Thought about ordering the blue, but there's the AFB nearby and I don't want some F35 Rocket Jockey trying to land on my driveway.

 just looked through my stock. Have three 12V 3A supplies, two 12V 5A supplies, one dual output supply putting out 32VDC @ 940mA and 16VDC @ 625mA from an old printer. And another 12V 4.5A supply. Geez! I got these things laying around all over the place.

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#### ErnieM

Joined Apr 24, 2011
8,214
Here are my two real world examples.

I have a fish pond and loved seeing it at night lit up with several solar lights, but I didn't like that shortly after midnight the lights went dark. I replaced them all with low voltage LED lamps and a small 60W transformer. Since it is a pond needing a filter I had AC run out there. I reworked the lights as they were actually way too bright as they came. The transformer I have has that dark sensor and I set it to run all night long.

On a lighthouse I used to work on there is a very professional installation (contracted by the USCG) of 10 solar panels, some 50W @ 12 volts each. 8 of them supply the biggest 1.2V cells I have ever seen in series to make 12V, which run the equipment in the light (still a listed aid to navigation). The remaining 2 panels were offered to us, and we (well, they, I was not involved nor consulted) did an amateur job of installing two deep cycle marine batteries. The panels drive the batteries directly, no charge controller; I checked the ratings of everything and it is actually coincidentally an acceptable arrangement with the batteries surviving 2-3 years before replacement. They power some lights inside and a marine stile toilet when people are there, and some up lighting every night.

Note these up lights are controlled by a simple timer and that timer needs to be set every couple of months least it come on way too early or late.