Hi all…
Im creating a small layout that is intended to be extra portable, and i was wondering if it was possible to power a transformer or powerpack from batteries?..is it?..can it be done?
Ryan
It can, you can buy throttles that hook up between the power pack and the rails, one of these should work. I am not sure how long the batteries would last though. Just curios: What type of batteries are you going to use?
i was thinking along the lines of a video camera battery…reason i ask is because in the videogame world there is a guy that takes systems that werent made portable and makes them…
The closest thing wold be some of the electric airplanes but their flight time is very short- couple minutes at most I think.
I’m wondering whether the current draw from a video game and a standard DCC system is going be two completely different animals - like comparing apples and oranges. I suspect that battery use on a DCC system won’t be practical. (Unless you are talking abouot a googob of Sony battery packs. Even then…)
Tom
Electric RC airplanes generally draw several amps of power. That is why they only fly for a few minutes. However, our train motors draw a fraction of an amp, 1/4 to 1/2 amp.
And you could use a much larger battery ie: 12 volt 7 amp/hr motor cycle battery. This would yield several hours of full power operation.
Why not look at Lithium Polymer cells?
They have enormous power density and are available in a wide variety of capacities. Best of all they are not hugely expensive, look one ebay, huge numbers are sold there for the RC car and aeroplane hobbyists.
I have one mad engineer friend in the UK who has put a stack of Li-Poly cells into an OO scale tender and uses a radio-remote system to control the loco. Depending on train size and running speed he gets between 90 minutes and three hours per charge.
Why did he do it? He is using a layout built by his grandfather. It has all brass rail and on DC it was barely passable, on DCC it was hopeless. But he is emotionally attached to it so one night in the pub we challenged him to make it work properly - so he did.
Milwaukee and Makita power tools both make Lithium Ion battery packs for power tools. They put out 24 or 28 volts, and if it can run a sawzall long enough to do any damage, it should be able to power a train forever.
But if you go with a car or motorcycle (deep cycle marine would be your best bet) battery, Wal-mart has cheap inverters for plugging in 110 volt AC stuff, and with a little southern engineering you could make a fancy battery box and have the plug off of the inverter right on the top where it’s easily accessible.
Greg
My prediction is that in the not too distant future, power cells will be powerfull enough and small enough that the power will be on board the loco and engines will be run via wireless remote. It will be the next step after DCC. It sounds like the fellow in the UK is already ahead of the curve on this.
shese…dcc…marine power…i had invisioned a simpler layout, right now, im looking at something rechargeable and able to power a single locomotive on a continous loop for about 2 hours…i figure if a camera battery can power a dvd drive, lcd. cpu of a PS2 for an 1 1/2 hours, than a simple power pack which i presume has all step down power converter stuff in it, can work…
If you hold a standard 9 volt battery to pickup wheels on an HO scale engine, it will run the motor most times. If you can find someway to control the power from a battery, I don’t see why it would not work.
Early large scale (G or whatever) trains were powered by arrays of D cell batteries mounted in tenders. Perhaps finding one of these and using their controllers would be an idea. They were contolled by radio too, so this might be something that could be used too.
Bob Boudreau
thats what i was hoping to hear, i just now stumbled upon a great idea…a battery like a 9 volt would be place at one end of the loop, a dimmer switch would be in the middle of it, while the other end would be the track…crude but it would work, not to mention conserve space…is there any harm to the engine doing this?..will it burn out the motor or cause damage?
what about N-scale…which this will be built upon…is their different power comsumptions?..
N scale has smaller motors and thus might be better suited for a portable power supply. Electric motors do tend to suck a lot of juice, no matter what size–a better power system might be a pair of 9v batteries, providing a potential peak voltage of 18v. There are many schematics out there for simple throttles–a power supply and a pot would work, but a basic transistor throttle would provide better, smoother control.
First of all - you defintely want a transistor controller, not a potentiometer or variable resistor. The resistor is used to reduce the voltage by wasting energy in the form of heat, thereby causing a voltage drop across the resistor and reducing the voltage to the motor. Very inefficient - in a battery rig you are looking for every bit of efficiency you can get.
Secondly, DCC is probably out. Not because of decoder inefficiencies - the pulse width modulation system is actually quite efficient. The problem with DCC is inefficiency in the power supply generation of the wave form being put on the track. All the DCC controllers/power supplies I know of require too much power for battery DC input, unless you went to a marine or golf cart deep cycle battery. Not all DCC systems can use a DC input either.
This site has several different traditional DC transistor controller designs. http://home.cogeco.ca/~rpaisley4/CircuitIndex.html
Running the calculations - most camcorder batteries are about 2400-4800 mAH. Of course, you won’t actually see that much energy, but at least 50% of the rating should be usable. This should be enough to run a 200 milliamp motor for quite a while.
The question is whether you will be happy with the output voltage of the camcorder battery. Using a normal controller, the maximum voltage available is going to be set by the battery - minus a volt or two for the semiconductor junctions (inside the transitors and diodes). Newer cameras are generally lower voltage than older (and batteries are smaller physically). But the largest current camcorder batteries are 9.6 volts or less. Getting more voltage (closer to 12v) means using 2 batteries in series.
Another possibility is up to 8 rechargeable AA batteries. AA rechargeables are available in a wide range of capacities, which range in price. I have found 4 packs of AA Ni-MH batteries rated at 2400 maH for less than $20. 8 AA’s yield max of 12V, 6 will give you 9V. Holde
Thinking about my post and AA batteries last night, had a couple of brain siezures:
If you went with a multiple AA battery solution, and you were able to accept quite coarse speed control, you could do away with the controller circuit and its losses altogether. Even a transistor controller is going to use a few milliamps - the greater the difference in output and input voltages, the greater the current draw of the controller. For the controllerless solution, the AA cells are wired in series, and an SPST switch is wired in parallel with each individual cell. Turning that switch “on” bypasses that particular cell. This would control track voltage in 1.5 V increments. Disadvantage would be uneven rate of discharge and “wear” of the cells, which could be alleiviated by rotating cells through the holders after recharging.
I then thought about the efficiency issue a little more. As with the transistor controller, motors generally tend to be most efficient at their rated voltage. Therefore, the optimum configuration from a battery life point of view would be to have the desired operating train speed occur about a volt or two below the fully-charged output of the battery pack. The difference allows for the battery pack voltage to decrease during discharge, which will happen. An example would be that the desired train gives the desired speed at 8 volts. Ideally, I would use a 9V rated motor and battery pack. Or, (again ideally) I would regear the locomotive to give my desired speed at 9-10 volts, and use 12 volt components.
Other issues affecting battery life are the current draw of the motor - less is better, free-running characteristics of the cars and locomotive gear train, grades, and curves. Another words, everything you do to reduce the load on the motor helps.
Answering your last question about using the DC portion of a commercial power pack as a voltage regulator (controller) for the battery pack - it depends. A good understanding of the various circ
wowzers…understanding that is like understanding the meaning of life…very impressive indeed, many thanks…though, slighty dumbed down would do…im hoping for a yay or nay on wether this can be done…
Yes, it can be done, we ran trains from car batteries years ago with a rheostat for speed control. Now for the tecnical stuff, I’m no electonic specialist.
If you hook four or five standard “D” batteries in SERIES, it will be enough to run most normal (non-DCC) HO locomotives. The Old Dog did it when he was a pup, and it worked fine. To increase speed, add more batteries. To decrease speed, remove some batteries. You probably could wire up a rotary switch for speed control.
As for using automotive batteries, be extremely careful! They can output a good deal of current.; The Old Dog has read of people getting files welded accross the terminals while trying to clean the terminals. Sounds like a good way to fry an engine!
Have fun
whats a rheostat?..and say putting a dimmer switch or similar in the middle of the circuit would control speed?
so this my idea…
go to radioshack they have battery holders, hook up the batteries(in the battery pack-holder) then go to home-depot by a dimmer nob normaly for room lights.
wire the dimmer nob, the battery pack, and the rail together.
would it work or could it be slightly modified to work???