12 volt solar panels and LED lighting advice please

Thread Starter

Tonyr1084

Joined Sep 24, 2015
6,459
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
3,852
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.
 

Thread Starter

Tonyr1084

Joined Sep 24, 2015
6,459
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
3,852
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
6,217
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
6,459
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
1,706
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

[A 100W panel at $140 is very expensive ! ]
 
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Thread Starter

Tonyr1084

Joined Sep 24, 2015
6,459
Externet that's a good suggestion. In fact, I've been considering something like that for lighting an area that someone unwanted might trespass in. Thanks for the suggestion.
 

ThePanMan

Joined Mar 13, 2020
129
If you want ambiance lighting then bright garden lights will probably fill what you're looking for and be far less expensive than putting a PVP on the roof and then running wires all over the place. It might be more effective to have a low voltage transformer pushing something like side marker lights for your driveway. If you don't want them to be real bright then add PWM to dim the light output of the driveway string.

I wouldn't go with the PVP on the roof. I don't like all those wires hanging all over a building. Besides, I wouldn't want to put holes in my roof. Even a new roof.
 

Thread Starter

Tonyr1084

Joined Sep 24, 2015
6,459
Thanks Pan (ThePanMan). As far as the driveway lighting, I think I'm going to go with something like this. Maybe even that part specifically. Using all 10 would only draw 1250mA (if you can believe the specs). A transformer would be a great solution. In fact, I have a transformer with a photo eye for low voltage pathway lights I don't use. All I have to do is FIND it somewhere in all my mess. As for the deck, I suppose solar lights should be OK. As long as they're bright enough to provide "some" illumination. Not necessarily something to read by, just to outline the deck. Again, all, I haven't made any firm decisions on what I want just yet. Still shopping for ideas, so options are still on the table. But it's looking like I may be drifting away from solar. However, in the event of a power failure, battery backup would be nice. Now I'm wondering if I can set up some sort of battery backup on the lighting for the driveway. I think the 12V transformer I have isn't internally rectified, so it should be capable of charging a 12 volt battery (12V * 1.414 = ~17V when filtered, as a battery would do).

Anyway, thanks all for the assistance. I'm sure it will happen, just not this weekend. Still working on flooring on the new shop. Then I have to bring the table saw up and start work on cabinetry for the shop.
 

MisterBill2

Joined Jan 23, 2018
9,838
For backing up the driveway in the dark I recommend adding some back up lights that shine down at the rear of the car so that you can see both the edge of the driveway and the back of the car with the driver's side mirror. That will help even if you have one of those OEM backup cameras that does not display anything along side the car.
 

Reloadron

Joined Jan 15, 2015
6,217
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
 

MisterBill2

Joined Jan 23, 2018
9,838
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.
 

Thread Starter

Tonyr1084

Joined Sep 24, 2015
6,459
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.

[edit] 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
8,196
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.
 

Thread Starter

Tonyr1084

Joined Sep 24, 2015
6,459
@ErnieM thanks for your input. There are a number of ways I can approach this. At present I've evolved to the idea of using one of those brick style 12V supplies I mentioned. Option 1 is to put it on a timer. Option 2 is to get one of those light sensitive switches like this and use that to control the PS. Running 18 gauge wire along the fence and splicing into it approximately every 8 feet (fence posts) and mount the lights in there. IF I were to use a battery then I'd need to find a way to keep the battery charged and only switch on at dusk. Here's a low voltage light sensitive switch. If I go the low voltage and battery route I would need to get a battery charger to keep the battery at float voltage. I've modified one of those power bricks years back to keep a battery at 13.6V. I still use it for a car radio in my work shop. I don't have a power supply big enough to drive a car stereo and deliver deep rich bass notes to the speakers, so I modified the PS so I could power the radio from a car battery. At the moment it's not set up because my new shop is still undergoing finishing construction. But soon I'll have that going as well. I will look into a device I've scavenged from one of those car battery boosters you keep in the trunk. It's designed to charge an SLA battery, then store it in the trunk. The battery was not charged frequently enough and has gone bad. I have another thread on that subject, but that's not important. The thing is 'I have options'.

That's interesting about the lighthouse. I worked for an emergency lighting company back in the early 80's. One job we did was to replace a series of NiCad batteries (1.2V wet cell 50AH each). The batteries were to be scrapped, so I grabbed a few dozen of them and took them home. WOW! What a punch those things had. I was going to use them to solve my energy needs for life - that never happened. But back then I was a novice to electronics and my understanding of batteries, even now it's not great, was even worse. I wouldn't have known how to charge them or to maintain them. Back then all I did was install them and change burnt out light bulbs. Occasionally installing more modern SLA powered emergency lights.

[edit] Note to all: The links provided have been sanitized to remove tracking tags. Everything from the question mark and beyond has been removed from the links. You won't be tracked. [end edit]
 
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