[Tom Farin]

I'll bet I'm not the only forum participant concerned about global warming and/or our dependence on foreign oil. As much as I'd like to convert my whole home to solar Photovolactic power, without more incentives than those available in Wisconsin, it currently doesn't work economically. Not on a system that would cost me at least $75,000. Besides, my major chunks of spare cash are putting two kids through college.

But I'd like to experiment a bit, preparing for the day when solar PV is a bit more cost effective. I ran across this article on getting your toe wet and gaining experience by taking a bedroom off grid.

http://www.off-grid.net/2008/03/27/take-one-room-off-grid/

I thought, "If you can do that with a bedroom, why not a garden railroad?" By the way, this approach could work for any of you that would like to run a GR in a location not close to grid power.

Why did I post this here? It's the battery power forum isn't it? /DesktopModules/NTForums/themes/mls/emoticons/laugh.gif Solar panels are being used to generate power which is stored in batteries. Power is being drawn from the batteries to power stuff. Sound at least a little similar to some of the other posts in this forum? Now if I could get Tony Walsham enthused about developing a radio control system to manage an entire solar powered railroad ... /DesktopModules/NTForums/themes/mls/emoticons/laugh.gif

Yes, the scale of the battery power in this project is somewhat greater than the scale of most battery power posts to this forum. But I consider this to right on topic for this forum. And you are the august group of participants in MLS most likely to be able to help me out.

My North Pacific Coast garden railroad almost came alive at the end of last summer. The track was laid. The golden spike ceremony was set. I just ran into a few last minute problems getting power to the layout. So a bunch of friends attended and complimented me on the static trains I had on display. I won't get into the power snafu here as it might subject me to ridicule from this group. But I've been obsessing about power all winter. Now that the 100" of snow we received in Madison, WI this winter has mostly melted, I'm about ready to get going.

The NPC was built to be a radio controlled, battery powered layout - the old fashioned way - packing rechargable batteries in tenders and battery cars. I also planned to light my structures with solar power outdoor light components. That won't change. You might say, "Farin, you're already off the grid with battery power and solar." That is an incorrect statement for a number of reasons.
(1) The batteries need to be charged. I'll bet most of you do it with grid power.
(2) I have a very nice string of old fashioned metal low voltage lanterns that will be used to illuminate the walkway running through the middle of the layout. Input to the transformer powering these lights is 120V AC.
(3) There will be a water feature requiring a lift pump to bring water from the catch pond at the bottom of a stream back to the top.
(4) I ran 20A 120V lines and placed outlets all around the layout for occasional and possibly unplanned continuous use.
So what I'm talking about is taking all of the above off the Alliant Energy power grid and substituting a small off-grid setup conceptually along the lines of that pointed to by the bedroom link earlier in this post.

I've researched the components and have refreshed my mind on electrical math. Five books on solar PV power are on their way from Amazon. So I think I can deal with the general issues - what components to use and how much capacity I will need. I plan significant overcapacity in all but the solar panels and battery banks so I can upgrade later.

Here's where I can use some help.
(1) Have any of you ever tried this stunt? If so, I'd appreciate learning from your successes. And from your failures.
(2) It seems ludicrous to generate 12V DC with PV panels, charge a 12V battery, invert the battery output power to 120V AC, then plug in transformers to convert back to DC to charge the batteries my engines will pack. Any thoughts on a shortcut?
(3) The same could be said for the pump that will move the water except the AC back to DC step would be skipped.
(4) The same could be said for the low voltage lanterns. DC to AC to DC.
(5) What are the gotchas I'm missing?

I'd also welcome comments from anyone intrigued by the idea that would like to network on implementation.

By the way, I realize this is not the most cost effective way to power a garden railroad. But then, is there anything about a garden railroad that is cost effective? /DesktopModules/NTForums/themes/mls/emoticons/crying.gif

It's a hobby, and an opportunity to learn something new while making a very token contribution to solving some of the problems we all face.

Tom

 

[Guest]

Tom,
I have a heart for Off-Grid Power, but I'm really only interested in less dependence on anyone (fed/state/local gov, foreign oil, etc...) and If the choices I make help the environment, so be it...
I mentioned in another posting that I'd like a small PV unit to power my MAHA Batter Charger so I could be a "Green RR", for no other reason, than the heck of it. Thought it was a cool idea!
Like you I'd love to have the funds to invest in a full-blown system to power my home or heat the water at my Salon...but it's just not there right now. So what do I do?....I'm taking another route for now, which reminds me I need to log off the train fourm and read some more on Home Brew Diesel for my truck...again for less dependence!
I have seen Solar lift pumps for garden ponds-google should help there! you could always replcae the bulbs in your old lights to LED's and power from solar (or even retrofit some solar bulbs into them)
Interesting stuff for sure! Good Luck
cale

 

[Del Tapparo]

Posted By Tom Farin on 04/03/2008 1:13 PM


(2) It seems ludicrous to generate 12V DC with PV panels, charge a 12V battery, invert the battery output power to 120V AC, then plug in transformers to convert back to DC to charge the batteries my engines will pack. Any thoughts on a shortcut?

Tom




Tom - It's actually difficult to find an AC input battery charger. Look at the R/C car and Airplane hobby shops. Most of their chargers take a 12 volt input, usually their car battery when out in the field.

 

[Guest]

Great Idea Del....nvr considered it! Pick up a PV from Northern Tool...and done!

Thanks, oh and Welcome into the world of LS Trains Tom!

 

[jimtyp]

For a charging batteries for a loco could you use one of those solar garden lighting systems?

 

[Dave Ottney]

The RC flying club I belong to has a solar panel charging a deep cycle battery at each field. The battery is connected to panel that allows us to connect chargers for flight packs. This works very well and gives us the ability to recharge packs without using our vehicle batteries. I can't see why this type of setup couldn't be used for model RR'ing.
Dave

 

[Tom Lapointe]

For a charging batteries for a loco could you use one of those solar garden lighting systems?

Most inexpensive solar panels provide only a few milliamps (1 milliamp - 1/1000 amp) of output, vs. the AMPS most LS locos require.
In short, to run a loco maybe an hour or so a week, you MIGHT have to have it on your "solar charger" ALL WEEK./DesktopModules/NTForums/themes/mls/emoticons/crazy.gif
This is also assuming LOTS of sunshine (no rainy or cloudy days/DesktopModules/NTForums/themes/mls/emoticons/unsure.gif ). I also would try it ONLY with either Nicad or NiMH batteries, NOT LiPo batteries because of their intolerance for improper charging./DesktopModules/NTForums/themes/mls/emoticons/sick.gif


/DesktopModules/NTForums/themes/mls/emoticons/blush.gifTom

 

[Tom Farin]

First of all, thanks for the responses.

Cale,
Thanks for the tip on solar lift pumps. After spending some time with Google last night, I found many are too small for the lift I need. On the other end of the spectrum are solar well pumps for watering livestock and the like - $1,000 on up. But there is a much wider range of DC pumps than solar DC pumps. I need to spend more time figuring exactly how much GPH I'm going to need. I should be able to find a solar pump or a DC pump powered by my solar setup that meets my needs.

Also, I calculated the power needs of my string of low voltage lights. Let's see, 18 Watts times 13 lights is 234 Watts. Assuming 4 1/2 hours of lighting per evening and 4 1/2 hours of sun per day (wisconsin average) it would require 250 watts of PV panel at about $5 per watt - Yikes - $1,250 worth of PV panels just to run the lights (not counting batteries and other stuff). As you point out, I could replace the 18 watt bulbs with parts from solar lights for about $7 a light --- $91 plus some labor - not a difficult decision to make. In addition I pick up a photo sensor at each light that knows when to turn it on and off.

Del & Dave,

Never even thought about the radio control battery operated car market. I know a whole lot more now than I did 24 hours ago. You are right. Take two 7.2 volt packs, wire them in series and you have 14.4 volts of battery power. 7.2 volts is a real common RC battery pack voltage available in a variety of NiMh battery form factors for different engine sizes and power needs. And you are right, there are plenty of DC chargers that take 12 volts as an input voltage and charge 7.2 volt packs. In addition if more voltage is needed, there are 8.4 volt and 9.6 volt packs.

Jim,

The reason why you want to go with a purpose built charger is to stop charging when the batteries are fully charged, trickle charge to maintain, and cycle batteries that are performing in a less than optimal way. I had been thinking about one of the Maha chargers and discovered last night that the MH-C204F can accept both 120V AC and 12 V DC. But the problem that creates is charging individual 1.2 volt AAA or AA batteries which once charged are pressed in place in a holder rather than soldered together in a 7.2 volt pack. I like the RC approach better as it offers a much wider range of battery form factors, voltages, and
mAH capacity ratings and would allow me to charge the batteries while still in the engines.

Tom,

You are right about the inexpensive solar chargers. But I'm planning on putting a bit more coin into my setup. A BP 3125 solar panel puts out 125 Watts for $580. 125 Watts at 12 volts is just over 10 amps. In 4.5 hours it would put over 500 Watts into a storage battery. At 12 volts, that's roughly 40 AH of potential re-charge per day. I'm thinking about starting with two 6 volt deep cycle batteries wired in series, totalling 12 volts. I'm still working on what I need for Amp Hour ratings on the batteries (based on load calculations). But let's assume 120 AH with a maximum discharge of 50% or 60 AH of usable stored juice. In normal days, a battery 50% discharged could be brought back to full charge in 1 1/2 days using the BP panel. I don't plan to run trains that often.

I'll use stored power in the deep cycle batteries to charge the NiMh packs in the engines. This setup should provide more than enough power for that application. What is holding up my design is working through the lighting and pump issues discussed earlier in this post. Thanks to Cale, with the issue of the lights out of the picture, it's really down to the current draw from the pump.

Again guys, thank you for your thoughts and help. Any additional thoughts on the pump issue, my math or any gotchas I've missed will be appreciated.

My $65 1000W DC-AC inverter just showed up from UPS. Now that you guys have helped me figure out how to do most of what I want to do with DC, I may just have to throw it in the trunk.

Tom

 

[jimtyp]

Tom, I think this is very interesting, I would like to see what you end up with.

 

[Dave F]

Phew.. I thought you were lost to the Live Steam crowd there for a minute...

 

[ConrailRay]

Tom,
Pretty interesting project.
I think you should convert part of your pond/stream to a working hydro-dam to replace some of the power " border=0>

Our local club is going to build a small layout for a local arboretum and was considering charging a battery from solar power and came across this site:
http://www.hightechscience.org/solar_express.htm

-Ray

 

[lownote]

This is such a great idea! So I have a couple questions--are you planning to use a solar panel for each charger, or one big solar panel that feeds a bigv battery, which then feeds individual chargers? Whatever you do, please keep us informed. I'm really interested

ConrailRay, that's a cool link--thanks

Beats me why we don't have an equivalent to the Manhattan project to work on alternative energy

 

[Tom Farin]

Dave,

I do have an investment in some live steam engines. While you might argue they are off the grid, they are not consistent with using renewable energy (unless you converted to a wood smoke box to raise steam). Most run on butane, a petrolium product. So no, this will be primarily a sparker railroad.

Ray,

Hydro-dam? Interesting idea. Are you aware of anyone that has ever done this in scale? No, please don't tell me if you know of one. I certainly don't need another project right now./DesktopModules/NTForums/themes/mls/emoticons/hehe.gif

Thanks to the link to the solar powered garden RR.

Lownote,

That's an interesting question. If you look back through this thread, my intention was to power lighting, pump and chargers with a single PV system. But thanks to Cale, I'm going to power my 13 path lights with 13 solar units. The verdict is still out on the pump as I can either go with a solar pump or a DC pump tied to my solar setup.

As for battery charging, it makes a lot more sense to me to use a single solar setup regardless of the number of chargers I want to hook up. My railroad will actually terminate in my basement (see following photo) and the charger setup will be down there. I plan to put a solar panel on my roof above the place where trains enter the basement and run the solar CD output lines to the basement where the rest of the equipment will be located.

Everyone,

There are two main kinds of PV systems. The first is grid-tied. The PV solar system is tied to power company power. When a grid-tied solar setup is producing more power than is being consumed by electrical devices tied to the system, excess electricity is sold to the power company. When the use of power exceeds the supply of power from the solar PV system, it is supplemented by power from the grid.

The advantages of a grid tied system are: (1) it doesn't require batteries, (2) all of the power being produced by the solar system is used (locally or by the grid), and (3) the solar system doesn't have to be sized to deal with peak power usage as peak needs can be met with grid power.

The disadvantages of a grid tied system are (1) grid-tied systems do you no good if power needs are nowhere an electrical line,(2) you need to get permission from the power company to hook your system to theirs, and (3) you need to invert the DC power produced by the system to AC to supply it to the grid.

Tying your PV solar system to the grid will probably require professional installation and certainly makes no sense if all you want to do is power a yard light like I'll discuss in the next post.

The advantages of a non-grid-tied system are (1) you can do it yourself as long as you conform to electrical codes, (2) you can have power in locations where running an electrical line could be cost prohibitative (like a Garden RR on your recreational property where you have no grid power), (3) Where the needs are small enough that it doesn't make sense to tie to the grid, (4) Where for moral, personal, or political reasons you want to be totally independent of the grid.

The major disadvantages of a non-grid tied system are (1) you will need to invest in storage batteries as your need for energy often occurrs at different times of day than when the sun is producing power, and (2) you may find yourself in a situation where you will need to overdesign system capacity to deal with peak load needs.

Having said all this, my experimental PV system aimed at powering my garden RR will be a non-grid tied system. In my next post, I'll cover my first step, the least expensive non-grid tied railroad application I can think of.

Tom

 

[Tom Farin]

Oops,

Forgot to include the photo.

The NPC garden railroad will enter my basement staging area through the culvert/window opening in the photo. The charging station, and the equipment for the non-grid tied solar system will be located in this area. The solar panel itself will be on the south-facing roof above the culvert.

Tom

 

[Tom Farin]

Here's an example of one of the simplest and cheapest off-grid solar systems available.



It is a stainless steel solar powered yard light available from Harbor Freight for around $5. I stuck two of these in beds last summer. Every night (almost without fail) the two lights turned on at dusk and supplied power well into the evening. We had a sunny day yesterday. They were still shining as the sun came up this morning.

The self contined power center of the unit is a disk about 5" in diameter and about 1" thick. Visible in the top of the unit are the light sensor (small dot in the bottom left of the top), and the Photovolactic unit (square in the center of the top).



Unscrew the four screws in the bottom of the unit and open it up and you will see this.



The large disk in the left of the photo is the top half of the power unit. The smaller disk to the right is the lower half of the power unit. The left disk contains the printed circuit board that is the brains of this device. The PC board takes incoming sun-generated power from the PV unit, converts it to the 1.2 volts needed by the rechargable battery in the right side, storing the sun's energy in the battery. It also contains a charge controller that cuts off charging to the battery when it is fully charged. This portion of the circuitry operates best when the sun is out, not quite as well in cloudy conditions, storing the electricity in the battery.

When evening comes, assuming the switch on the right disk is turned on and the light sensor detects a low light condition, the brain will begin pulling current from the 1.2 volt battery rectifying the voltage to that needed by the LED and turn on the light. The LED will continue to produce light until either the battery's voltage falls below the minimum allowed by the brain, or the light sensor indicates that it is daylight.

The LED would not normally be visible in this photo. But you can see it laying just to the left of the center in the left hand disk. Its two silver leads originally protruded through the two holes dead center in the right disk. The two leads were attached to the green and blue wires laying loose in the right disk. To remove the LED, I merely shipped these wires and pulled the silver leads through the holes by tugging on the LED located on the non-visible side of the right disk.

Why did I destroy the electrical continuity of this neat little unit? Because I wanted to adapt it top an alternative use. Read more in the next post.

Tom

 

[Tom Farin]

You don't need to know anything in the last post to use a solar powered yard light. Turn on the switch, stick it in the ground where it will receive light and use it to illuminate pathways around your railroad. But this cheap $5 self-contained off-grid PV system can be adapted to a variety of other uses.

But before doing so it is useful to understand that LEDs are not light bulbs. LED stands for Light Emitting Diode. The diode is the electrical equivalent of the plumbing check valve. A diode allows current to move through the device in one direction, but not the other. A Light Emitting Diode produces light when the current moves through the diode in one direction, and is completely dark when current attempts to move in the wrong direction. So it makes a difference how a LED is wired into a circuit.

The two leads coming out of a LED are the LED's cathode and anode. Generally the cathode is marked in some way. With the Harbor Freight LED there is a flat spot on the diode's bottom next to the cathode. The cathode was connected to the green wire before the leads were cut. You don't need to know the difference between a cathode and anode. You just need to know that when you reconnect the spliced wires, the green wire needs to be reconnected to the cathode and the blue wire to the anode.

The most common reasons for separating the LED from its incoming wiring is that we want to increase the distance between the power unit and its LED or change its orientation.

One other thing about LEDs. They produce more light per unit of power than any other lighting device priced at less than a king's ransome. And they last nearly forever.

Powering Your Garden RR Structures Off Grid

Say you spent 20 hours putting together your steam engine house. To be prototypical, you want it to light up at night. You could run wires from the grid and light a grain of wheat bulb in the engine house. But what a bother. First of all you would need to run wiring. Then you would need a switch to turn the lights on and off. Then if you want to take it inside out of inclement weather, you would need to disconnect it from the grid. If it's raining and you're in a hurry, you'll probably forget, yanking wires out of the ground. As Winnie would say, "Oh Bother."

Of course, you could power that nasty power consuming incandescent grain of wheat light with a locally contained battery. You could use a light sensor to turn the lights on and off. But then you'd need to change batteries as those power hungry grain of wheat bulbs run them down. We build railroads to run trains, not to perform maintenance. Have you wondered why most traffic signals have been converted to LED lighting?

On the other hand, we could splice about a foot or so of wire between the the LED leads and the blue and green wires in our Harbor Freight power unit, mount the LED inside your structure, and place the control unit in a sunny location, maybe on the back side of the structure's roof. But there would be this big power thing mounted to the back side of the roof of your otherwise-pristine engine house. But with a bit more creativity you might be able to remove the light sensor and PV unit from the power unit, splice some additional length into the electrical lines feeding those devices and mount the electronics under the roof and just the PV and sensor on the roof.

Doing so would substantilly cut maintenance and allow you to move the whole thing inside in inclement weather.

Best yet, you could brag to your friends that your engine house has a "complete self-contained, off-grid Photovoltaic system". Then you could launch into an explanation of how an off-grid PV system works. You know, the PV unit, the electronic brain, the battery storage, and the controls over your LED light. Those bragging rights would come at the princely cost of $5 and a few hours of your time. And in a tiny little way, you'd be reducing our dependence on non-renewable energy sources and making use of our vastest renewable source, the sun.

Cool. /DesktopModules/NTForums/themes/mls/emoticons/hehe.gif

Tom

 

[Tom Farin]

I bought 13 of these Malibu low voltage lights at pre-winter close out at Home Depot around 6 years ago. They are all metal powder coated lights. My recollection is they listed for around $40 apiece and I paid around $20. they are as close to a railroad lantern as anything I had seen. Their boxes have been decorating my shed until this spring.

In a few weeks, the 13 light string will illuminate the walkway running through my garden railroad headed down to my pond. They represent a great little case study in the issues of using solar power in a Garden RR. I'm going to look at three alternative approaches to powering these lights.

GRID POWER

The approach I had planned to take is to pick up 100' of gauge 12 low voltage cable ($50), string the lights down the cable and power the lights with a 300 watt Malibu transformer ($100) plugged into 120V AC courtesy of the grid. Assuming my cost in the lights themselves is sunk, my total up front cost is $150 plus my labor.

But that's not the end of the costs. 13 lights with 18 watt bulbs consumes 234 watts of power. Assuming they are lit 4 hours per night, they will consume 1 kilowatt hour of grid electricity per day or 365 kilowatt hours per year. At a cost of 10 cents per kilowatt hour, my electrical cost is $36.50 per year.

Assuming I also replace six 18 watt bulbs per year, my maintenance costs (exclusive of my time) will be another $16.50 per year.

SUBSTITUTE SOLAR POWER

Assume that I power the same lights using the same low voltage power cable with solar power. I will save the cost of the transformer ($100) and the annual cost of the electricity ($36.50).

But a self-installed complete off-grid PV system is estimated to cost about $7 a watt. In Wisconsin, daily full sun solar radiation averages 4.5 hours per day. Given that I gather power 4.5 hours per day and light the lights 4 hours per night, the solar generating capacity of the PV system would need to be roughly 234 watts. At $7 per watt, the system would cost $1,638. Net of the savings from eliminating the Malibu transformer, I'd be out about $1,500 up front. Based on the $36.50 annual electrical savings, my payback on my $1,500 net investment would be OVER 40 YEARS.

You could validly argue that my payback calculation fails to consider the increasing cost of electricity over time. I could validly counter that it also fails to consider the time value of $1,500 spent now against future savings in energy costs. But our arguments would be moot. At age 62, I'm never going to see a return on my $1,500 investment.

The above example illustrates why most people feel solar power is not a cost effective solution. But this next example will prove that assumption wrong.

REDUCE POWER CONSUMPTION THEN SUBSTITUTE SOLAR POWER

Pick up any book on installing a PV system and you'll find the first recommendation in the book is to focus on reducing power consumption BEFORE sizing a PV system. That's because steps taken to reduce power consumption often have very short payback periods. A good example is replacing incandescent light bulbs with compact fluoresent bulbs. The case is so compelling that some states have enacted statutes REQUIRING the replacement of incandescent bulbs with CF bulbs.

But beyond that, a movement to PV solar power forces you to change the way you think about power consumption. You are moving from a situation where power feels like it is unlimited as long as you are willing to pay a nominal cost (10 cents a kilowatt hour where I live) for your additional power consumption. You are moving to a situation where additional power is extremely expensive ($1,500 for 236 watts of solar PV power).

I found a good example by accident in following the TOC/GR/Bachmann controversy. By the way, in spite of the fact I've crossed swords with TOC once or twice in the past, I'd defend to the death his right to free speech. But that's not my point.

I stumbled across an article TOC wrote at the GR Web site explaining a potential modification to the Bachmann K-27. It involved removing the LED from the headlight and substituting a grain of wheat bulb. That recommendation comes from a world where asthetics are important and additional energy has been really cheap. The esthetics of a more prototypical color warmth produced by the grain of wheat trumps the minor additional energy cost in TOCs mind. I understand TOCs viewpoint as I've lived there all of my life.

But were TOC to find it necessary to pay for the additional energy capacity needed to PV solar power the electrically inefficient incandescent grain of wheat bulb as compared to the very energy effecient LED, he might be forced to make a different decision. This very small example represents the change in priorities we all may be forced to make as we deal with global warming and our dependence on non-renewable energy sources.

The TOC grain of wheat/electrical cost concept directly applies to my string of yard lights. The problem with powering the yard lights with PV solar isn't the cost of PV solar power. The problem is the highly electrically inefficient 18 volt incandescent bulbs.

What if I were to substitute a white LED for the 18 volt incandescent bulb in each of my 13 yard lights? What if I was to power each LED with the self-contained off-grid solar PV unit provided as part of the $5 Harbor Freight Yard lights? How would that change the economics of my decision?

I would save the cost of the Malibu Power pack and the 100' of low voltage cable ($150). I would save the annual cost of grid power ($36.50). I would save the annual cost of replacing the 18 volt bulbs ($16.50) -- the LEDs are unlikely to burn out in my lifetime.

And it would cost me $65 for 13 Harbor Freight lights. I come out $85 ahead up front and save about $50 per year.

"But what about your labor, Farin?" I'm betting that my up front labor investment won't be significantly greater in converting my 13 lights to solar than the initial time needed to string the cable, attach the lights, debug the system and set the timer on the grid based system. Annual time savings could be significant as I won't be squatting on old legs to change bulbs and won't have to deal with interruptions in my electrical line cause by critters and shovels.
It's time to get the soldering iron and solder out. Step one will be to solder the LED to the two terminals shown in this photo.

Once I've done my first conversion, I'll post some conversion photos.

Tom

 

[Dan Pierce]

Why just think solar, think windmill for generating electric power.

Also, windmill for pumping that water. It only flows when the wind blows.

 

[TonyWalsham]

Tom,
I am reading your thoughts with great interest.
Have you considered that the incandescent bulbs actually radiate light very well from the side, whereas LED's generally are very directional and don't radiate light from the side very well at all.
You may have to construct a special pcb insiide the lantern holding multiple LED's pointing sideways to radiate light through the frosted lens.

 

[Guest]

to add to what Tony said...well not really, but another thought...I use the 12v GOW bulbs in my engines, very little draw...and a nice light?