Ok so I am in the planning phase of my shed layout and I will be powering everything off of solar and a battery bank. My question is is there a way to eliminate the need for an AC power inverter and convert or modify my transformers somehow be them dc or dcc so they don't need to be hooked up to AC power? It seems like a waste and extra cost to go from dc to ac back to dc. Plus inverters will put a lot more drain on the batteries than if the transformers could run directly off of a dc battery bank. Anyone done this? Thanks guys.
Cool project. I would hate to see this post dissapear without a response... DC should work with a rheostat hooked on a 12v battery ( or two). An RV battery is probably what you want because they are designed for continuous operation. DCC is AC 18V, so an inverter is a must...Maybe someone with more advanced knowledge will reply...
Simon
CTConrailOk so I am in the planning phase of my shed layout and I will be powering everything off of solar and a battery bank.
am I correct that the solar panels simply recharges the (car) batteries and the batteries supply a constant voltage for your layout, 12V
you should be able to use buck-booster converters to efficiently generate a variety of voltages (5V, -12V 14V) from the batteries.
i think the toughest will be to convert the battery voltage to 14V for DCC at relatively high current (5A)
greg - Philadelphia & Reading / Reading
If you don't mind the trains running a little slow, the nominal 13.8 volts from a lead acid battery bank will provide enough voltage to run a DCC system. Just be sure tyo FUSE EVERYTHING. A battery bank like that can source enough current to literally weld things which would quickly destroy any railroad electronics. If the command station draws 5 amps - no more than a 6 amp fuse on the line feeding it. Otherwise a fault on the unit could destory it, or, putting the kind of current the battery can produce through something like #12 wire, you could burn your whole shed down as the #12 wire glows, the insulation melts of fit, and any flammable material in contact with it catches fire before the wire melts through and breaks the circuit.
Scary - but completely safe if you use proper fuses on the circuits - right off the battery set you should have a fuse block protecting the various circuits.
Julien Ilet, a YouTube producer who does mostly electronics videos, powers his workshop via a bank of batteries and a solar panel. Everything he does ends up running through boost/buck converters, or he charges power banks and runs his experiments off them instead of live connected to the shed's power system.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I am not quite sure yet on what my solar setup will be however it will probably just end up being 12 volt panels At least 200 watts each hooked to a charge controller and a series of deep cycle batteries. All the panels do is keep the battery bank charged. Everything will be fused as rrinker suggested. I have built a solar powered generator before that has the option to be run and charged off of a wind turbine as well so I am not new to solar or working with DC. It has an inverter though so in addition to USB and cigarette lighter ports it has AC plugs as well for household items. I know it would be easy to just run DC however I am leaning toward DCC to have better control of multiple trains at once. I know little to nothing about DCC as I have just started getting back into the hobby and DCC was very new and expensive when I stopped model railroading. I know how DCC works as far as how it sends signal to the decoders but I don't know much about the Controllers thenselves. Don't know if it could be converted to run off of DC power or not. I know it will be easier to just get a nice inverter and run my setup off AC power like the controller is designed to and if there is no feasible alternative solution thats what I will end up doing. I just figured why buy an inverter and switch to AC power if I am already making and storing DC power at the battery bank.
Finally, someone else with this idea. I always wondered what it would be like to run trains off of solar. Keep us updated!
I'm beginning to realize that Windows 10 and sound decoders have a lot in common. There are so many things you have to change in order to get them to work the way you want.
This won't be a commercial install I will be doing it myself and buying the panels batteries etc separately. How exactly does that buck converter work? As far as when you tested it with your DCC? You didn't need to have anything at all hooked into a wall outlet?
CTConrail I know it would be easy to just run DC however I am leaning toward DCC to have better control of multiple trains at once.
How something like DCC works is unimportant.
i believe almost any model railroad electronic device can use DC power through a wall supply. You just need something to convert your battery voltage to what that device requires.
buck-booster converters as Mel described efficiently convert voltage from some source to either a higher or lower voltage. I believe some of the converters Mel uses have variable outputs.
Common regulators drop voltage, wasting power (heat) in the regulator. But buck-boost converters switch currents on/off quickly to avoid wasting power when dropping voltage or using the disruption of a current path thru an inductor to actually increase voltage.
others can check me on this, but it looks like these 2A step up power booster modules from ebay could be used for things that need more than battery voltage which Randy said is actually 13.8V. Here's a 6A converter
these 3A step-down converters could be used for voltages less than battery voltage (5V, 9V, 12V)
Solar panels and converters aside: What kind of temperature swings is this shed going to experience over a 12-month period? Trains won't be much fun to operate if your layout track is buckling because of a lot of expansion/contraction. Moisture and dust is another matter to consider.
So, will your solar panels be used to operate overhead lighting, air-conditioning, and/or dehumidifiers?
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
Most DCC systems can use AC or DC input - previously, they all used basic AC power supplies, so the first thing inside the case after the power input terminals was a bridge rectifier - so they can work on DC input as well. Typically the DC input voltage needs to be a couple of volts higher than the AC, to get equivalent voltage to the rails, but slightly low isn't going to hurt anything, the trains just won't run as fast at full throttle. Most newer DCC systems come with or use what is basically a laptop computer power supply, DC output. Those newer ones often can NOT work with an AC input, they expect DC only.
DC is pretty easy, just about any DC throttle circuit takes a DC input and generates a varying output, plus has a direction switch to reverse polarity. Back in the day, this is how many layouts operated - car batteries and rheostats. That's also why in many cases, pre-war early HO used 6V motors, because most cars had 6V electrical systems in those days. There's definitely nothing new about running from battery power - the new thing here is charging the batteries with a solar panel instead of a trickle charger.
You can get nearly anything in "12V" - lamps, certain typesof appliances. Often used on boats. Friend of mine did this years ago, he actually ran 12V outlets in his house and ran it from his solar/battery bank and used 12V lamps and so forth instead of running it through an inverter and stepping it up to 120VAC. There was no connection at all to the electric utility - it gets MUCH more complicated hen you do that because you need tranfer switches and other gear to keep your system from back feeding the AC mains, which can be deadly to line workers who think they have de-energized a section of wire only to have some yahoo with solar or a generator feeding power back in from their home.
Thanks for the detailed explanation Mel. Big help and it seems like this is the way I will be going. I didn't consider that part fully Tom (temp swings) however If will be insulating and finding some way to heat the shed for winter. We will be moving to South Carolina so thats where it will be. Not quite as bad as where I am now in Connecticut but still gets cold and definitely hot. I will also be insulating the shed and putting up wood paneling over that.
Whatever the nominal (at-the-time) voltage output is of a battery system, you'll need more than that to charge them...correct? So, if the battery or bank of them has a nominal capacity upwards of 12-13 volts, you'll have to be able to charge them with even more voltage. A 12 volt solar panel will be inadequate. Someone correct me....
i don't know. But my assumption is that output voltage of the panel is not likely to the best for charging a battery. I've read that it varies with sunlight.
Therefore, I assumed it was the OPs issue to sort out and his question to us was can he drive his model railroad stuff off a car battery.
I think some have expressed a concern that the battery voltage maybe different when charging and not charging. Fortunately the buck/boost devices can handle varying input voltages.
It does seems that buck/boost concepts can be used to adjust the solar panel output for charging a battery or some desired operating voltage. It seems some devices designed for solar energy management may be more intelligent than others to optimize charging current depending on sunlight conditions. Interesting stuff
I would just use an inverter and build everything with off the shelf components. You are not going to lose much efficiency by using an inverter. Your lighting, heating and cooling are going to use more power than your trains anyway. Unless you are buying RV lights and heating those are going to be AC. I have been using solar panels for my RV for several years. I installed the whole system myself. The biggest problem is that deep cycle marine batteries have to be replaced every few years just like a car battery and they can be expensive.
selector Whatever the nominal (at-the-time) voltage output is of a battery system, you'll need more than that to charge them...correct? So, if the battery or bank of them has a nominal capacity upwards of 12-13 volts, you'll have to be able to charge them with even more voltage. A 12 volt solar panel will be inadequate. Someone correct me....
Voltage is not the issue. It is the standard. Just like all of the electronics in your car are 12 volts DC and the power in your house is 110 volts AC. Batteries are rated in Amp Hours, how many amps they can hold. If a battery holds 100 amp hours it can output 100 amps for one hour or if the load is only one amp it will last 100 hours. Solar panels are rated by watts. So the charging power is based on the wattage of the panels. If he uses two 200 watt panels he will have 400 watts, but it is still at 12 volts DC. So for the rest of his power needs over 400 watts he will need to tap into the stored power of the batteries.
Lone Wolf and Santa Febut it is still at 12 volts DC.
the panel? even in dim light?
The actual voltage output of the module changes as lighting, temperature and load conditions change, so there is never one specific voltage at which the module operates.
Panel vooltage is fairly constant, the current varies with light intensity.
Yoou don't just hook the panel _ and - to the battery _ and -, there are charge controllers you use in between. Julian Ilet designed his own but it's based off an open source hardware design, plus there are commercial ones. You don;t want to overcharge the batteries, or it will literally cook them, and you don't want battery voltage feeding back into the solar panels. The charge controller takes care of this.
There are a lot of good YouTube channels that cover this and other topics - done by people who have a clue as to what they are doing. Good places to learn. There are also a whole lot of charlatan types out there who pretend to know, but it's not all that hard to seperate the wheat from the chaff if you watch what each does. The good ones rapdily become obvious. Same goes for pretty much any topic you can think of that's covered on YouTube - I don't just follow electronics, there are some good mechanical type channels to watch as well.
rrinkerPanel vooltage is fairly constant, the current varies with light intensity.
do you mean the solar cell/panel output or the output from any converter circuitry?
Everything I've found out suggets the voltage remains constant, it's the load you can apply that varies based on the light incident on the panel. Such as
https://forum.allaboutcircuits.com/threads/solar-cells-and-mppt.93863/
If the load remains the same, but the light decreases, the coltage will drop, but that's because yoou are exceeding the maximum supply current.
wouldn't that suggest there is no internal resistance that affects output voltage depending on current?
It's not zero (no such thing in the real world as an ideal voltage source), but solar cells, at least the common type used in the kind of panels you'd put on your roof, do have a very low internal impedence. One of the other articles mentioned that open circuit voltage on a typical "12V" panel is more like 18-24V, but as soon as you put a load on they fall into the proper voltage. There are some graphs of that, which show the from some current draw up to the maximum, the voltage is flat, but exceed the maximum current and it falls off sharply. Where that peak lies depends on the panel area and the amount of light incident on it.
I know those old inexepensive solar cells they used to include in those XXX in one experimenter kits, and which could be bought cheaply even back in the 70's, did not behave the same way as the silicon cells. I remember when Radio Shack first satrted selling the silicon ones, they were insanely expensive for just a very tiny panel - and they were extremely brittle. I forget what the cheap ones were - selenium perhaps - but they did widely vary voltage based on the amount of light, or else they were so low output that even a fairly high impedence meter put enough of a load on them to drag them down. I distnctly remember experimenting with one and could tell when I was positioed over a light source by the voltage swing, in the same fashion as using a CdS LDR and measuring the resistence. That would be about the time I nearly set the family room carpet on fire because I was usine a 120VAC neon lamp as the light source and the wires running to the wall plug touched when I shifted things around. Somewhere in a junk box I might even have that neon lamp, with one of the connecting lugs burned off. Youthful experimenting before I really knew better - I couldn't have been more than 8 or so.
Dcc requires ac. the ac is the signal carrier over the dc current. To go dcc requires the coverter. I have a solar panel set up similar to what you are reffering to for job site work. I use trickle charge battery maintainer panels through voltage regulators to deep cycle batteries. The panels just slow charge the batteries. I only use a few amps an hour so it works fine. Like most of us, you would only be using it a few hours a week.
I would still ise fuses and requlators coming off the batteries as protection from spikes remember shorts, they will dump full amps from the battery Makes for the First train in space. So check you amp useage and fuse accordingly. Will not hurt the batteries to be housed outside the shed.
As for dc power, who remebers the extented handheld throttles MRC made. The power came from the dc connecting on the power pack. They would be perfect. And cheap
Wolfie
A pessimist sees a dark tunnel
An optimist sees the light at the end of the tunnel
A realist sees a frieght train
An engineer sees three idiots standing on the tracks stairing blankly in space
NVSRRDcc requires ac. the ac is the signal carrier over the dc current. To go dcc requires the coverter.
the AC DCC signal is generated by the command station. The command station doesn't necessarily require AC power.
In fact the newest DCC systems from Digitrax and the newest boosters from NCE COME with DC power supplies.
The old ones that used AC power supplies, open the case on any of them - the first component connected to the terminals where you connect the power supply is a bridge rectifier - the thing actually runs on DC anyway!
They are called 12 volt panels but they are definitely made for charging a 12 volt battery system. Thanks for everyone's input. I haven't even bought my property yet or got the shed however I like to have everything plannnd out so when it comes time I know which way I'm going and what I will need to buy. I may just end up going with an inverter but I don't know yet. I guess it depends on how I will end up heating the shed as well.
Perfect timing of this thread for me. I'm just getting back into the hobby and helping in the early phase of a layout at a visitor center and convinced to go DCC, but I live off the grid (micro hydro) for 22 years and now convinced to go DCC at home. I have 12VDC and post inverter 120 VAC wired throughout my house and cabin. It seems to me that DCC should be able to run off of 12VDC just slower. Perhaps the DC -DC booster is just the answer. It would save me 22 watts per hour if I could avoid the AC power. The output of the AC power supplies for NCE is DC voltage, so the AC signals traveling to the track must be generated by the power cab. Is this correct. I hope it is. Does anyone know if the power cab needs the full amperage full time?
BTW CTConrail, if I go DCC at home, I'll let you know how it comes out.