Solar Panel + Super Bright LED Strips for Night Sign

[mitekcomputers]

Hi,

I have been in the computer industry for over 30 years, own a sales and service center full time for the past 16 years, and have just built a new shop on my property.

My only issue is I purchased a 2500$ canned sign 5 feet long 3 feet high years ago (1 side not a dual sided sign..aluminum case with a frosted raided letter lexan insert with our company name and phone number blue and white) and it normally runs on 110 volt no problem, and uses 4 x 5ft cool white fluorescent tubes. Of course NOW where I need to place the sign is almost 300 feet from my new shop and I do not want to run super heavy duty copper underground cable that far first because it's super expensive and secondly well because I just do not want to. Rent a trencher, pile drive beneath a blacktop driveway, dig a ditch 300 feet, run the cable, cross a creek.. tough as tough can be.. just way too much labor and cost involved.

I have my electricity with a rural coop energy company so of course they want to charge me a ridiculous amount of money to set a pole (400$), install a service panel and meter ($250), and then charge me 35$ a month (their minimum charge) to power a sign that would only cost maybe 5 bucks a month to run in a bad month on a normal electricity run.. pisser..

So I am thinking I coudl swap out the fluorescent bulbs for some super bright 12 volt bright white 5 foot LED strips, install a solar panel and a battery and just run the sign completely off solar. The only issue is I have NEVER dealt with solar ever and do NOT have a clue as to whether this woudl even work or not. In theory it sounds good and parts etc would probably run in the 250-300$ range which is MUCH less than the electric companies bid and a LOT cheaper than 300 feet of copper

I figure a 100 watt solar panel with all of the necessary hardware, a good deep cycle marine battery in a waterproof box, and then all of that connected to a day night sensor that in turn would control the LEDs.. on at dusk off at dawn kind of thing would work just fine BUT.. Im simply not sure if it would work at all. Could I get by with LESS panel or do I need more? These are the kinds of questions I need answers to.. I need to save as much money as possible BUT I dont want to scrimp either. I have never dealt with solar before so other than what I have read i am pretty much clueless.

My question I guess would be is 100 watt solar panel too big, too small, or what..will I actually need something that large to run 4 or 5 x 5ft LED strips overnight for say lets assume 12-14 hours nightly on the darkest days of winter (Im in Ky) ..should i use 12 volt LED system straight from 12 volt solar, of should I simply just use a standard 110volt ac inverter and then use a wall wart to drive normal LED bright white strings.. is there any difference?

I want to do this the correct way but as economically as possible where this simple one sided lit can type sign will stay lit up at night which shows my company name and phone number. It works great with normal cool white fluorescent bulbs, BUT I truly believe i can do this with solar which in the long run will prove to be much less expensive that running normal electricity 300 feet or so underground.

I am located in a rural farming community with very lax zoning laws. so anyone with any ideas I am totally up to listening. I do not want to start a solar project IF it is doomed from the beginning to fail. My business is doing extremely well, BUT I do need this lit sign up and running at night time just so people know where we are located as it can be hard to find IF you are not familiar with the area.

Thanks in advance for any help or insight. It will be sincerely and deeply appreciated..

Mike/Mitek Computers
www.mitekcomputers.com

 

[Red Squirrel]

Could definitely be done, get 2-3x as much solar wattage as you figure the sign will draw, then put solar panel on top of the sign or other area where it can get the south sun. (you could do tracking but that's getting more complex, just point at the south, tilt it enough so snow can usually fall off and should be good). You then need a charge controller and battery. If you go LED try to get something that can run off the same nominal voltage, ex: 12 volts. Otherwise you will also need an inverter or DC-DC converter.

So basically:

Solar panel(s) (something higher than 12v, 24v is good)-> Charger controller -> 13.5v out -> battery

Then load runs off the battery. The charge controller's job is to efficiently get power from the panels and properly charge the battery. With lead acid what's nice is you can easily charge a battery while it's in use, so the load just runs straight off it. Some charge controllers have an option to cut power to the load if battery is too low, you'll want to do this so you don't completely kill the battery if there's not enough sun or panels get covered in ice etc.

Will take some maintenance of course like adding water to the battery cells once in a while, but definitely doable, and best of all once it's done it won't cost a thing to run. You could even throw a wireless router and an arduino in there to monitor temp, voltage, etc if you wanted to.

 

[mindless1]

5ft fluorescent tubes are an odd length, normally 4ft, but admittedly I don't know a lot about signage and it wouldn't surprise me if some were set up with less than the most common tubes. Anyway, If they were std 4' T8 tubes then you'd figure they put out about 3000 lumens each.

THEN the question is, do you need to shoot for the same amount of light, which I assume was acceptable but what about less light? If it's dark all around this sign then you may easily be able to get away with less light opposed to a lit city environment. That is where the quest starts, determining amount of light and going from there.

Do you really need on at dusk and off at dawn? That's a significantly longer runtime than just on at dusk and off at, whatever, maybe midnight if not earlier? This choice could just about cut in half the battery capacity you need. Some numbers:

A rough ballpark for lumens per watt is 100lm/W. There are more efficient LEDs than this and someone can easily make one near twice that efficiency, but ready made strips or not running DIY designs well below the max LED rated power, 100lm/W is a place to start. Now if you have 4 x fluorescent tubes at 3000lm each, you need 12,000lm to replicate that. Actually a bit less if designed properly because the LEDs only shine forward in roughly 120' beam instead of the 360' of the fluorescent tubes, with some % of that loss due to reflector inefficiencies if there is a reflector at all.

If you get LED strips designed to run at 12V, you may be getting something with a DC-DC (current regulated) driver built in, or it could be a lot worse and have integrated resistors for current limiting which wastes a lot of power on the sale that you're going to need, so while that type may be cheaper I wouldn't settle for those as you're going to probably pay at least that cost difference and more for a larger battery and solar array to compensate for the power loss.

Considering all of the above, I might shoot for around 8000 lumens, at 100lm/W is 80W. If you factor that an LED driver(s) can be around 90% efficient, that's 89W or close to 7.5AH @ 12V nominal battery voltage. Next factor for how long it needs to run. There are "on at dusk, off after (n) hours" type controllers out there. I don't have product to recommend but they must be available for solar powered garden lighting if nothing else, I even have one that switches 110VAC but you're looking for ~ 12V DC input.

Suppose in winter you want it to run from 5PM to midnight, that's 7 hours at 7.5A is 53Ah. You'd want some margin on the battery capacity so it doesn't drain too deeply or else you won't get near the lifespan out of it, so with that in mind a 100Ah deep cycle can be had for around $175 if you shop around a little, probably higher at a solar panel oriented seller. Just make sure it's a true deep cycle and not a "deep cycle and starting" battery which can't drain as low.

If you take the 3X solar capacity figure Red Squirrel suggested then for the above you'd need about 240W worth of solar panel, except perhaps more for the controller inefficiency, yet at the same time maybe you don't need to run it till midnight in winter, this is one of several variables you'll have to consider. I just don't see people wanting to come to a computer shop after midnight except maybe in NYC. It's also a good idea to have a low voltage cutoff circuit involved or a miscalculation, dark day, or snow on the panels could ruin a battery, particularly if it's power a wide input LED driver instead of a simple 12V strip with an inherent dropout voltage not too far below 10V.

I definitely wouldn't involve an AC inverter unless you want to use two batteries instead of one, and at least 50% more solar array capacity. The one benefit to doing so might be that if your current lights are 4' fluorescent instead of 5', there are drop-in LED tubes you can run from those. However they are only 2/3rds as bright and some are pretty poorly made, not sure how well they'd stand up to winter in KY. Something else to keep in mind is snow removal off the panels.

My calculations above may be way off base. I mean that you might be able to get away with only a couple thousand lumens which is more in the ballpark of what you'd get with the cheap 12V powered LED strips, and although I mentioned above that those using resistors are less efficient, the fewer lumens you need, the less expensive that loss is. I've really typed too much already without a better idea of the brightness and runtime requirements, but runtime is easy enough, if I wrote 7 hours and you want 14hrs then just double everything.

 

[Micrornd]

I'm admittedly not solar "educated", but Kentucky in the wintertime?
I don't see anyone compensating for the batteries being outdoors in below 40F - maybe as low as 20F.
Doesn't this have to be compensated for?

 

[mindless1]

^ It can get colder than 20F in KY on a winter night, and the batteries will have degraded performance, but in a setup where they're draining at a rate as low as C/7 if not lower still, the current demand relative to max a battery that size can sustain is low, you'd still be within the margins you'd want anyway to not discharge too deeply.

Main thing is to have the low voltage cutoff circuit, then no matter what battery array you choose, if it's not enough you won't damage it, can just add another one in parallel. You might want to nearly equalize the voltage before hooking it up in parallel to the rest. Something as common and inexpensive as a power resistor can do that, though an AC-DC charger will usually top them off close enough. Then again when people jump dead car batteries they just ignore all that and the world keeps spinning...

 

[Red Squirrel]

Idealy you'd have an insulated cabinet of sorts for the batteries, charge controller, etc. If it's one of those thick neon signs there may even be room to put all the stuff inside the sign, in it's own smaller compartment. It would then be temp regulated by opening/closing louvers automatically for airflow. You can probably get away with like 0C so you only need a very small heater. I would also set the cut off threshold rather high, like 12.0 volts (including the heater). When you hit nominal voltage it's basically the half way mark. Normally you'd go down to like 11.0 but I'd go to 12.0 to compensate. A temp compensated charger will help too as the charge rate is higher when it's cold. Could also try to bring them to like 25C during the day if there is excess solar energy that can be used up. This is getting more advanced and into micro controller territory though, you can probably get away without lot of that stuff, but it will increase the life of the equipment.

 

[mindless1]

^ The batteries and electronics should be kept out of rain and snow, but they will tolerate cold weather, at least as cold as KY gets they will function fine for this purpose. Think about everyone driving around in cars in winter? They had to start them, right? This just isn't a large enough load on a battery of suitable capacity to run for hours, that it would have any trouble producing enough current.

You'd either have to use battery power to generate heat which is counterproductive, losing more than you gain, or run a power line out to it which eliminates the need for batteries. You don't need a temp compensated charger on a solar setup where the panels themselves are the limiting factor. You want the highest charge rate they can provide, then just a cutoff at peak charge voltage, no need to even trickle/float charge when the sun rises every day. I mean this within the context that the solar panels are a budget constraint, he won't have infinite or an excessive amount of solar panels available to do the job.

 

[Fardringle]

One significant question that others have mentioned here is: How much light do you actually need? If it only needs to be visibly lit at night, you can probably get away with a lot less light than you might expect. For example, I have a flashlight I carry around a lot with a single 500 lumen Cree XML2 LED emitter, and that thing is blindingly bright at night running off of just three Sanyo Eneloop 2000 mAH AA rechargeable batteries and it will provide that much light for about two hours before it starts to dim a bit, and it is still fairly bright for quite a while after that until the batteries drop below 1 volt and need to be recharged. If I take the head off of the flashlight to let the LED shine freely in all directions instead of being focused, it lights up a 15 foot square room better than a 60w light bulb.

A couple of those strategically placed around the sign (even just four with one near each corner) would make the sign quite bright, especially if it does not have to compete with ambient light from city street lights, and you could run it all night off of a fairly simple battery pack that can be easily charged with a 100 watt solar panel, and it could easily run for a week or more off of a 12 volt deep cycle battery if you want to go that route.

Now if you do want it to be lit up very bright like the average city billboard sign, then you need to go a lot more complex (and more expensive) with full LED strips, deep cycle batteries, and a larger solar panel as other people have suggested.

 

[sm625]

I'd be surprised if you needed more than 20 watts. I would build up a 20 watt sign and test it out. Then add whatever you need to make it bright enough, if needed. After you have the sign looking how you want, then calculate the size of the solar panel you need.

 

[herm0016]

https://www.amazon.com/Renogy-Watt-..._rd_wg=g1wTw&refRID=DH8HAXA39BKMBPRRJMMA&th=1

something like this will probably work. I have put similar systems on a couple campers and they work well for my 12v ARB fridge and lights and such. You wont get much cheaper by getting the components separate.

 

[mitekcomputers]

Thanks all for the amazing ideas and education. I think I will simply go with the brright white 12 volt leds, a deep cycle marine battery, a day night switch and timer and the 50 watt panel. I checked and they are 5 foot lights with teh single center pin on each end. I always had to special order them from a local electrical company and they were broght white type lights,,,extremely bright for flurescents for sure

So LEDS/Solar Panel/Battery.Insulated Battery Case.day night switch with timer..everything around 300$ and that shouldwork just fine and would pay for itself over the period of a year IF I had to install a pole and service box or use any other method..so sounds liek a heck of a deal to me

Mike

 

[Thebobo]

Wow your way out there, get much drive by work? Looks like a nice area. Always love to pics of folks work area for ideas.

 

[mitekcomputers]

Yeah well it looks like we are way out in teh boonies but in all reality we are only 4 miles from Berea and 10 miles from Richmond BUT where I live and have my shop is a small farming coimmunity so things are rather spread out,,, in fact I live on a farm thats been in my family for 3 generations and it is where my home and my computer sales and service shop is located. In all reality I do just as much business where I am now as I did when i was located inside the city limits of Berea in a street that went staright to WalMart...so one of the most traveled streets in a small town for sure. My sign was what attarcted a LOT of customers according to teh customers themselves. They would normally say I saw your sign when I was driving by last night or one night etc...

So its important that I do get THAT sign up for night time for sure (busy major highway) and we do get a lot of drop in work from people that see our swooper flags and signs , banners etc.. BUT at night time and because it is so dark here I want the night canned sign because it will be very noticeable and much brighter than your normal outdoor security lights that everyone in rural areas has installed. I really dont need the sign on after 3am BUT I would like it coming on at 4 am going off at daylight, then coming back on at dusk and running until at least 2 or 3.. its really deaad here after 1am I believe with very few travelers at that time of night

But everyone in this area goest o work at 7 am...so if I could have it come on from 4 to 7 or 5 to 7 that would be awesome too, People would definitely notice my canned well lit bright white sign at night out here in this dark rural area...for sure

And I know it would bring in even more busiess simply because it is an eye catcher.

Mike

 

[AD5MB]

I would put the solar cells on top as noted above, in a box that shields them from view. some people just have to steal solar panels and some people just have to break glass.

 

[mitekcomputers]

See next post.

 

[mitekcomputers]

The general consensus seems to be a 50 watt solar kit powering 12 volt bright white leds that would be replacing the fluorescent tubes in a standard canned type sign like what you would see above doors on a retail brick and mortar shop. We use a canned sign as opposed to channel letters

So a 50 watt kit, a waterproof battery box, a 12 vool deep cycle battery, a day night timer amd south facing which i have . I would place the solar panel on TOP of the canned sign or one of its poles so it is always taking advantage of soutward sun.

This shoudl work in theory if all I need is teh sign to be brightly lit between say real dark at around 9PM and run with sign on through 2 or 3 in the am because after 2am there is very little traffic so running it between 2am and 5am would be a moot point. I would need then the sign to come back on around 5 or 6 am and run through real daylight. Then off again until true dark. 7 days a week every day.

I would be using a deep cycle 12 volt battery stored in a weatherprrof battery box..I would make sure to have timers etc I need in order to follow the time periods i need on and off.

So I can REALLY get by with a 50 solar watt panel and not a 100 watt panel ... would you guys agree or not.

If i have a pole and service box installed to power just that sign it would cost right at 500$ for teh electric compmany to do it plus 35 bucks a month proofminimum. If I ran a weatherproof copper underground cable from my shop to the sign, just the cost of the cable alone would be prohibitive PLUS I have to figure a way to cross a creek thats 30 feet wide.

So Im trying to go as green as possible, so the right thing BUT also do it as cheaply as I can and where it will actually work perfectly. I could use a little help here for sure. This is my ffirst time ever even looking at solar power and I realize ythis is probably simple for many guys,BUT all new to me.

Thanks.

Mike

 

[herm0016]

do some math. ~ 10 hrs per day x wattage of your lights = watt hours per day. etc... to figure out how much panel you really need. I think 100 would be good, 50 may work but your sign may not be very good when its cloudy for a few days.

 

[mitekcomputers]

Yeah no matter what I keep coming up wit ha 100 watt system would definitey work best in this sitaution. i swear Im just about read yt orent a trencher and just run cable... seems liek a hwole lot of work and products just to get a sign to light up every night to be honest whem I can simply run an underground cale from my service panel and be fished with it. I woudl take forever to make the mponey back to pay for the "green" system... no wonder more peopel dont do it.. its way to expesnive and way too complicated,,

Just a pain in teh ass no matter how you do it,,,

Mike

 

[Mr Evil]

You could get a 50W panel, and if it's not enough then get another 50W panel and wire it in parallel to the first for 100W total.

 

[Red Squirrel]

Something to keep in mind too is how long are your nights for most of the year, vs days. You want enough power and enough battery to last the night. I would go with at least 100w myself as you never truly get the plate rating of a panel. The LED strips probably won't use that much power so I'm thinking you could get away with a standard RV/boat type battery. At least start with that and see how it works out. Every 6 months or so you'll want to go add distilled water to the battery to ensure it lasts so make it easy enough to access, but secure enough that it won't get stolen.