Large Scale Central

Laptop PS for Command Station?

Electronics Power and Sound
#1

Has anybody out there used a laptop power supply to to power their DDC command station? I see that many command stations say they require a digital switching power supply such as the soon to be released Marklin CS3.

Here in the US it os possible to obtain new Dell laptop power supplies quite inexpensively. They have a fixed 19.5V DC output, are self-resetting short circuit protected and depending on the model, have maximum power ratings between 90 and 150 watts (4.62 and 7.7 amps). Am I correct in thinking these may be suitable for powering a command station for large scale use?

#2

a little low on voltage, you lose a couple of volts through the booster… also you won’t be getting the full output current from your booster…

what booster are you choosing?

Greg

#3

If running on start up set tracks (4 foot diameter) then these computer power packs will work great.

Several manufacturers make 5 amp DCC systems where these can be used.

I have an indoor layout with 4 foot diameter track and this would be great for running my trains.

Outdoors, I would want more power (24 volt minimum and over 10 amps so I purchased the Zimo 20 amp unit.

Under the Xmas tree I use a 5 amp system, MTS serial only that I have only $50 dollars invested in.

#4

In terms of the voltage, figure out how fast you expect your trains to run. If you have a power supply now, and your trains run plenty fast with that, then that’s a good ballpark for the voltage you would “need” for your DCC power. For example, I model early 20th century narrow gauge, so I don’t need voltages in excess of 15 volts to reach “prototypical” speeds for my trains. Contrast that with Greg (above), who runs modern mainline stuff. He needs 24 volts to get his trains to run prototypically fast. Different railroads = different requirements. While 24 volts is often used as the “norm” for large scale DCC track voltage, it’s not mandatory. I’ve got an MRC system that gives me 15 volts to the track, and a Piko system that gives me 20 volts. There’s no difference in performance in terms of functions (sound, motor control, lights, etc.); they just run a bit faster at 20 volts. For my personal situation, I’d find a 19-volt power supply to be perfectly acceptable.

Having said that, while you may find your 19 volts to be sufficient, the 7.7 amps may be a little low depending on your power requirements. (I’d definitely shy away from the 4.62 amp supply.) How many locos are you looking to run at any one time, and how much current would they draw? I would consider 7.7 amps good for two “average” trains. Usually, 10 amps is considered the practical minimum for a power supply, but if you’re running shorter trains, I’d think 7.7 amps would be good for two or three locomotives without issue.

From a practical standpoint, the oft-recommended power supply for large scale DCC is a MeanWell 24v/10a unit. That’ll run you in the neighborhood of $50 or so. (If you look on Greg’s site, I’m sure he’s got a specific model number somewhere.) Look at what your needs are, compare the prices of the Dell units vs. the MeanWell, and go from there. At the worst, you save a few bucks buying the Dell power supply right now, find that down the road it’s a little underpowered for your needs, then swap it out with a more powerful unit. You’re not spending a ton of money on the Dell power supply, and it’ll be easy enough to repurpose it elsewhere as maybe a workbench power supply or for lights and accessories for the railroad. It’s a safe gamble to make if you think it will work right out of the gate for your needs.

Later,

K

#5

Just a couple of words of caution:

A genuine Dell or other supply is one thing. A Chinese clone might not be of the same quality level, especially in terms of short circuit protection or overheating.

These supplies are not designed to run at full bore continuously. That said, you might not be running your system at full output either.

In my case, I often run the layout at 10 amps continuously, and that takes some rugged components.

My advice, although I would still like to know WHAT system you are running, is to try it out and monitor the temperature, and test the short circuit situation.

Greg

#6

Greg and I use a 30 volt 20 amp supply in order to get 24 volts to the rails with our Zimo MX10.

There is a voltage loss in the command station and a little more in the decoder.

Therefore the motors never see 24 volts nor does the V+ line go to 24 volts although it is close to that.

So, if you have 24 volts oin to a command station, you will not see this on the rails due to loss through components.

Now what happens to systems with 21 volt input…

This is why when you want late model diesels to approach prototypical operation you need 24 volts on the rails and still can not get acela speeds (the Boston to Washington train hits 160mph in Mansfield MA, track is rated for 165mph).

#7

I use a 24V 15A regulated power supply to power my Digitrax command station. The power supply has a potentiometer, I have mine dialed back to just under 20V since the Digitrax dumps extra voltage beyond that as heat. This is the link, http://amzn.com/B01CS5G8J6 It’s only $21.49 Free Shipping for Prime Members

PS

#8

Phil, what system are you powering? NCE/Digitrax, etc?

Greg