Solar Lighting Update 2013

At the time I thought it would be too much hassle to run 12 volt lines all over my railroad, so I started experimenting with solar lighting. I wrote an article describing my research and experiments.

Since then, I've extended 12 volt lighting to most of my railroad, so some of the things I tried to accomplish with solar lamps have been accomplished with other methods. However there have been enough minor developments since I wrote the original article that it might be time just to rewrite it.

General Comments About Solar Garden Lamps

Solar garden lamps promise A: convenience, and B: energy savings, compared to other technologies, such as 12-volt lighting. I think they deliver on convenience, as long as you buy the right product for the job you want it to do. On the other hand, I'm not sure that they really "save energy" in the long run - chances are it takes more energy to make one of these devices than they'll ever give back. (Anybody who knows otherwise, feel free to correct me, as long as you have actual facts.) In this article we'll focus on the convenience aspect.

Update for 2013: Although I originally predicted that this technology would be bringing us at least incrementally better devices every year, solar lighting has not advanced that much since I wrote the original article. New battery styles have been introduced, including the 2/3AA battery that makes smaller profile lamps possible and the 2.x-volt AA cell that powers some of the larger fixtures. Ironically, the new batteries may cost you more to replace than the fixtures, meaning that - for all practical purpuses - the lifespan of your fixture is even less than it was in the days when you could cost-effectively replace the battery. Another apparent advance is that companies like Westinghouse are claiming dramatic gains in brightness over "ordinary" solar lamps, whatever those are.

How Solar Garden Lamps Work - Most solar garden lights have a small solar panel that converts sunlight into a trickle of energy. That energy goes into a circuit that charges a rechargeable battery, usually a Ni-Cad although lithium batteries have emerged and NiMH batteries are possible. They also have a light sensor (sometimes built into the solar panel) that tells the circuit when it's dark out, so the circuit knows to stop charging and start sending electricity to the LED.

An LED - "Light-Emitting-Diode" - is a small mostly plastic electronic device that glows when it receives low voltage DC. It actually gives way more light per volt than a traditional filament bulb, so it's well suited for solar garden lights.

Because the LED is so small, its bright pinpoint casts razor-sharp shadows and can keep your eyes from adjusting to the darkness if you look right at it. So most solar lamps use a diffuser of some sort to "spread out" the light a little. The old black plastic flying saucers just used a milky outer shell that, unfortunately, caused the lamp to glow rather than to shine on other objects. The next generation often used clear "panes," but to keep the LED's light from being a pinpoint, they also used some sort of diffuser, usually a clear plastic tube with lots of crystal shapes molded into it. Today's lamps may replace the diffuser with a refractor - a cone-shaped reflector at the base of the lamp that directs the LED's light outward in all directions.

Most Solar Garden Lamps Still Use "Bright White" LEDs - For years, solar garden lamps used LEDs that gave off a warm yellow light they usually called "amber." The light from amber LEDs is pretty dim, but it does look relatively "natural," as though it comes from a gaslight or candle. Today, most solar garden lamps today use "bright white" LEDs that give off a light that's almost as blue as the old mercury vapor streetlights. Many of the new lamps give more light than their predecessors, but anything they illuminate looks relatively "cold and lifeless." A few manufacturers have experimented with "warm white" LEDs. These have a tinge of gold, which makes the overall effect seem more natural. Unfortunately these haven't really caught on yet for garden lighting.

How Can You Tell if a Solar Lamp is Good or Not? - You can't tell how much light a solar lamp will give or how long it will stay lit just by looking at it in the store. My limited experience shows that lamps that have more than one LED are brighter, and they don't necessarily go out any sooner. Also, lamps that have 2 batteries tend to brighter and last longer than lamps that only have one battery (unless the battery is one of those new 2.x-volt cells). Generally, though, you won't get into a lamp that has multiple LEDs and multiple batteries unless it also has an expensive "carriage light" framework or the like that will be too big to use on your railroad itself. In a couple of years, even the cheap ones may be as bright as the expensive ones, so if all you can afford to "cannibalize" right now are the cheap ones, experiment with those.

How Can You Tell if Solar Lamps Will Work For You? Most of them need a few hours of direct sunlight every day to reach their full potential of brightness and longevity. If your garden railroad is in heavy shade, or even mostly shaded, you may not be a good candidate for anything solar. Sorry. :-(

Solar "Street Lamps" on the New Boston and Donnels Creek

Back in 2006-2007, I looked for the smallest stake-mounted solar lamps I could find, then disassembled, painted, and reassembled them to make them take up less visual space on the railroad. Obviously they had something like fifty times the bulk of a scale street lamp, but they did the job. The results of that experiment are described in our original article.

Minilamps to the Rescue - Nowadays, with the advent of the 2/3AA battery, it is possible to make a cheap solar lamp with a much smaller diameter than the lamps I was using in 2006-2007. Our article on minilamps researched an eary iteration of these. (BTW, about a third of those original purchases have now failed. I don't know if the batteries have gone bad or the circuitry. But since the batteries cost more to replace than the lamps, I haven't done anything except put them in a box for later.)

In the fall of 2012, our local Walmart bought a bunch of "special purpose" minilamps in for .99@, and I bought over a dozen to use during our Christmas-themed open house. They were "bright white," which wasn't a problem for a Christmas display. I used them mostly to mark paths, boundaries, and obstacles so folks wouldn't wander where they shouldn't or bump into things after dark. After Christmas, I pulled all of the minis out of the various parts of the yard and stuck them on the railroad mostly to keep them out of the way as I did other yardwork. But as you can see from the title photo, there was something to be said for having them light up the railroad once the Christmas lights were down and I no longer had the 12-volt system running.

By February, most of them were barely working, so I figured that I'd gotten "my use" out of them. But by April 1, most of them were glowing brightly again, and staying lit for hours after sunny days. Will I buy more? Probably.

There was one diference between the first batch of minis I bought at Meijer's and Big Lots and the minis I bought at WalMart. The earlier batch had more diffusion, which is to say than when you plugged it into the ground next to a building, it cast a dim, but fairly even glow. The new batch has a strongly-ridged clear shell that casts a sharp star pattern. That's not a problem for me, since I generally only use these for supplemental lighting, but if it was a problem, I'd consider lightly sanding or otherwise reshaping the shell. That said, if you have no lighting at all on your railroad, and you'd like to be able to see anything after dark, the easiest and one of the most cost-effective ways to do that would be to go to WalMart, pick up a couple dozen of their $.99 minis and plop them like street lights around your buildings and communities.

Solar "Flood Lights"

While I was finishing the original article, I bought two of the little rock-shaped lights that are supposed to be like little floodlights on closeout at Big Lots. I hadn't bought any yet, because they're made so that if you have the "floodlight" part aiming away from you, the solar panel is on the side you see. Duh. And several solar "floodlights" I investigated years ago were a joke. But for half price, I thought I'd give them a shot.

I was pleasantly surprised. Fully charged, each of them gave about as much light as one of those pen-sized pocket lights, not enough to illuminate a wide area, but enough to provide a "bright moonlight" effect on a small town or farm scene, etc. Like the more traditional lamps with the bright white LEDs, these provide a "moonlight" or "mercury light" effect that washes out color. Each rock has four "bright white" LEDs. I'd rather they had three "bright white" and one amber LED just to provide a slightly more natural lighting effect.

The ones I bought shoot somewhat upward, so that I had to set them on a 30-degree slope to get them to illuminate stuff on the ground. I put one behind a "barn" so that you can't see it at all from normal viewing positions. Since these photos were taken, both of these have stopped working, by the way, but mechanical damage was probably at fault in at least one of the failures. Maybe the $50 ones last longer.

I've "passed" on buying the more common floodlight type, the one that looks like a one-eyed, one-legged, one-armed alien balancing a tray, because to illuminate any of the features on my railroad, I'd have to position these things where they were painfully obvious. In addition, I found some inconspicuous 12-volt LED spotlights that fulfilled my needs. (Those products are described in this article.) Unfortunately the 12-volt LED spotlights have been discontinued, so recommending them to readers is no longer an option.

In April, 2013, I went to WalMart to buy some bug spray and discovered that they had a new stock of 99-cent minilights, so those are still an option for anyone who wants to try them. I also discovered that the big Westinghouse floodlight that was almost $20 last year was $10 this year. It was still ugly, but what made me think it might be worth trying was the packaging which claimed that they were "Fifteen times brighter than ordinary solar lights." My rock floodlights needed to be within three feet of the feature they were illuminating to have any noticeable effect (two feet were better). But if these would illumate a feature from several feet away, I could maybe position them behind trees and such.

I guess it all depends on what you mean by "ordinary solar lights." If you mean the first-generation amber lights, the manufacturer's claim is probably accurate. But the new light is not 15 times brighter than my $10 Big Lots rock-shaped floodlights. Five times, maybe. I found a position for the one I bought that would hide it from the average viewer while still getting afternoon sun and casting a certain amount of useful light on a freight station. But I won't be making any broad recommendations. By the way, WalMart had other lights that were much more money and were supposed to be even brighter. Maybe they are. The question is do you really want to buy a $50 light to illuminate an $80 building? Better yet, can you wince hard enough to avoid seeing the tray-balancing one-eyed aliens all over your railroad? H.G. Wells would be proud.

More to Come

Hopefully, things will continue to improve. But I wanted to record my recent experiences for the sake of folks who are just thinking about these things for the first time.

In the meantime, I have to confess that being able to see my railroad, even a little bit when I pull into the driveway after dark is kind of fun. It's a little like my communities have decided to "leave the light on for me."

Your Input Needed

Obviously, if you have other updates or experiences that would add to this update, please let us know and we'll publish any ideas and photos we get from folks.

Reader Feedback (From the Original Article)

I applaud your efforts with solar lighting and wish to add a bit of my experience.

Although I've only put solar lighting into two of my RR buildings, I've tried numerous brands of solar lighting around my yard. To this end, I've yet to find any manufacturer's product that lasts more than a few months before giving up. Often the supplied battery goes bad and when replaced, the unit never works as original. More often than not, the electronics merely quits, either from moisture of my sprinklers or just poor engineering design.

The only success I've had was using a formal 5 watt solar panel to daily charge a deep cycle battery which is wired to the lights. Not quite the simplicity one would like in this type of effort.

Hence, I'm going to wait to hear a couple testimonials from someone who actually claims they've used a "store bought" system for more than a few months.

[We'll keep you posted - ed]

John Blessing, of Tucson, Arizona, writes:

Hi Paul,

Another grand issue, thank you.

I have a comment on the Out Door Lighting thread. We have purchased for Anozira RR some LED, bullet shaped, spot lights, which we have tested mounted on a pole to illuminate segments of the pike. As being spot lights, they shine down on the track areas, flooding light to where one needs to see. Experimentation with height above the ground, the angle to set each bullet-lamp, and how many lamps per pole to effect the coverage required is simply an exercise of diligence. We have found that the floods illuminate the track and way such that train operations are easily seen and the walk areas are lighted also, and unobtrusively well that folks can move about in safety with out stumbling, tripping, and going where they should not.

We have invested in two types of flood lamps: a Malibu, model LZ413, set of 3 each, 3 LED bulbs per lamp, energized by one solar cell array; AND another Malibu model having 1 each light comprised of 6 LED lamps energized by one solar cell array.

Each lamp in 3 LED bulb/light set is not as bright as the 6 bulb lamp, which makes the light flooded area more subdued/softer, but also each 3 LED lamp will not illuminate as much area. However, since there are 3 lamps in the set, one can mount them to illuminate a much wider expanse of area. That is kind of nice too because each lamp can be set to either blend with its neighbors, or set to illuminate spots with darker areas in between lighted spots. Interesting to watch a train pass from one lighted spot to the next, sort of like going through a connecting tunnel.

The light housing are flat black. We are to mount the lamp(s) on steel poles that are the pipes used in home situation, chain link fencing. So all the hardware is easy to acquire from Lowes or Home Depot to make the poles look stylish such as the fennel on end, clamps upon which to affix each lamp array. All are galvanized. All available in different diameters and lengths.

I have not installed any yet as our Tucson weather has been too hot for me to be messing with the RR much.

Vince (last name withheld by request) writes:

With reference to page located at http://familygardentrains.com/primer/lighting/solar/solar.htm detailing using cheap Chinese solar lanterns for illuminating model railroad layouts - two undesired features are mentioned as problems: short runtime of the lights, and unattractive color of the lanterns.

Both of these are rectifiable with a few extra parts and a little elbow grease, for those who have the time or inclination. Poor runtime is often caused by deterioration of a low-capacity NiCd rechargeable AA cell in the lights - as the solar light is a low-power device and the different chemistries can trickle-charge the same way, in most cases a AA NiMH cell is a drop-in replacement and will power the light all night (assuming the solar cell supplies enough power to charge the cell sufficiently during a day).

Most lanterns use NiCds because they are cheaper, lighter (save on shipping) and because most people don't care if their garden lights are still on at 3 or 4am or not. :)

The colour of the light can be altered by swapping out the LED. "White" LEDs are actually high-intensity blue LEDs with a thin coating of phosphor over the LED chip - this phosphor absorbs some of the blue light and fluoresces red and green, to produce a semblance of full-spectrum white light. As you'd imagine, the thickness of the phosphor is critical, too much and the light is too yellow, too little and the light is too bluish.

White LEDs after manufacture are often sorted into lots based on white purity, the ones that aren't pure white are sold cheaply and often used in these lamps to shave a few more (fractions of) a cent off the purchase cost. White LEDs with too much phosphor are sold as "warm whites" for those who prefer a yellowish cast to their light.

If you (know someone who) can use a soldering iron, you can easily replace the supplied LED with a whiter or yellower white LED for a nicer effect (make sure the replacement is around the same way as the original, as LEDs only work one way, unlike torch bulbs). If desired, you could instead put in a blue or possibly even a "UV" LED for special effects. Red, pure yellow or green LEDs like a lower feeding voltage and probably won't work or will fail quickly if used in this way, however (though they may last - haven't tried a swap myself yet!).

White LEDs with a pure or yellow cast can be obtained from places like eBay, or suitable (defunct?) consumer products like torches that have the colour you are looking for. Salvaged LEDs often don't have the long leads, but pieces of insulated wire can replace these. Don't heat the LED too much with the soldering iron if you try this, or you might damage it.

Hope this helps - Vince

Vince Redux

I asked Vince whether it was safe to use NiMH batteries in a solar circuit meant to charge Ni-Cads, and he sent the following reply: When charged with high currents (e.g 2hr or 1hr chargers), it is correct that you need a charger that knows how to treat the different chemistries of NiCd and NiMH cells, as they do somewhat different things when they get full, and a NiCd-only fast charger could indeed dump enough energy into a NiMH cell to cause it to overheat and pop. Containing water, if they get too hot the water boils and turns into steam with a massive increase in cell internal pressure, which can indeed lead to rupture or explosion, though the cells should be safety vented these days so they instead just leak their corrosive guts all over the place and into the innards of your charger instead. :) They don't tend to work as well at storing charge afterward!

Extended trickle charging is somewhat bad for NiMH cells, but only at relatively high current levels (say > 5% of battery capacity/hr). It would take a beefy garden light solar cell and a puny AAA NiMH cell to get near that limit, and the cell should be discharged mostly or completely overnight anyway. As the solar cell would be about the most expensive component, most designs are likely to be limited in night runtime by the low output of the solar cell rather than limited capacity of the battery. The highest output solar cell on a lantern I've seen is 30mA and even this relatively high current is unlikely to damage a 600mAh AAA cell applied continuously (as opposed to intermittently, for 8-12 hrs per day). Modern cells contain chemicals to eliminate gas buildup under extended trickle charging - the energy is converted to heat instead, and under low currents like what a garden light solar cell supplies, the cell can't get hot enough to be damaged.

Long story short - a garden light isn't a microprocessor controlled charge station and isn't designed to baby the battery to get the theoretical limit of approx 1000 discharge cycles, so don't be surprised when the batteries crap out after a year or two, no matter the chemistry - but the low charge currents from the solar cell pose little risk of overcharge damage to a NiMH cell.

One note: if the solar cell doesn't output enough current to fully charge even a low-capacity NiCd cell, swapping in a NiMH cell won't give you any extra runtime. If you need to replace dead cells, NiCds are cheaper, your solar lantern is weak, and you can recycle the toxic dead NiCds - those are the ones to go for! Where I live, NiCds are difficult to buy new, and only fractionally cheaper than similar physical size NiMH cells with twice to three times the capacity and no toxicity, so I'd generally go NiMH without a thought, but "your mileage may vary."