im changing my layout to a double decker. was wondering how would i know if i need a dcc booster? will it just be basied on how many engines im running or how big the layout is?
How many engines you plan to run. Figure on 0.5A for a sound equipped locomotive, so 10 on a 5A booster is a reasonable estimate.
In fact, it may be even more, because it depends on the amount of current each decoder/motor combination needs to operate.
If you exceed the booster's capacity, it will shut down if the current draw is excessive, or if the amount of current demanded is causing excessive heat. It is your choice if you wish to use two boosters or not, depending on your needs. But it won't hurt to split the layout into power districts so you can add another booster later, if needed.
Resist the urge to buy a booster with more current output, because it can do a lot more damage if a short occurs compared to the typical 5A booster.
How big is your layout, and how big is your room? There is a bit of loss per foot of track, but for the average room-sized layout it won't matter much. It's more the kids nd of problem a club layout might have.
The suggestion to divide your layout into multiple power districts separated by rail gaps and each protected by its own circuit breaker is a good one. If your layout is made up of smaller segments, each with a small number of amps allowed, you don't have to worry about having a large booster.
It takes an iron man to play with a toy iron horse.
Hello All,
Take a look at this thread:
How many DCC boosters are needed for an HO scale layout?
With DCC the thing to keep in mind is technically there are two (2) components to it; signal packets and power.
In DC there is only power. Which is modulated through the rheostat in the cab or "controller" and supplied to block(s) via switches on the control panel.
That's why with DCC there are standalone command stations- -throttles (signal packet only), combination command stations and power sources (signal packet and power), and booster stations (power only).
I will limit my comments/observations to the NCE and Bachmann Dynamis DCC systems, as that is what I have experience with.
Please forgive me if I get too basic...
Boosters (power) are rated in amps; 1-, 2-, 5-, 8- and 10-amps.
This is the amount of maximum "power" available to drive a load. Boosters can also be ganged together for more amperage- -more on that later.
DC motors are rated as amperage draw (AC motors are also rated in amps but that's another discussion.)
Motors in older HO locomotives can draw 2 or more amps. Modern, more efficient HIO motors draw 1/2- or 0.5 amps.
Larger scale motors draw more amperage to power larger motors to pull heavier loads.
Some DCC manufacturers understand this and only recommend larger amperage boosters for larger-scale locomotives.
This value is cumulative- -10 locomotives drawing 0.5 amps = 5 amps, no matter the scale of the model.
Command stations generate the signal packets that communicate with the decoder for things like motor output and functions; lights, horn, bell, etc.
With DCC, both power and signal are combined, and sent through the rails--via the track output of the booster.
The strength of the signal going to the booster is a different consideration from the power output (amps) that drive the DC motors in the number of locomotives in use.
Signal strength can diminish over distance. Most DCC manufacturers recommend a signal "booster" (repeater) every 40 feet of signal bus length.
This has nothing to do with how many locomotives you can operate.
Weak signal strength- -going into the power booster- -can cause erratic operation of the DCC decoder, which can mimic a lack of power to the DC motors of locomotives.
Contrary to popular belief, you cannot over-amperage a DCC layout.
You can overvoltage- -which will fry components; decoders and motors. That's another thread...
My pike is a 4'x8, DCC in HO.
I run two (2) consists simultaneously, that draw 3-1/2 amps, total load. I also have three (3) additional locomotives that draw 1-1/2 amps for a total of 5 amps when everything is running at full power, which is rare.
The booster (power) is 5 amps.
Some will argue that 5 amps on a 4'x8' pike is overkill.
The power draw of the locomotives dictates the necessity of this "size" booster- -not the opinions of others.
If I choose to run more locomotives simultaneously I would need to add a booster (more on that later).
Because the signal bus is under 40-feet for the entire pike I don't need signal repeaters (signal boosters).
If my signal run was over the recommended 40-feet then I could install powered Universal Throttle Panels (UTPs).
These UTPs are powered by a "wall wart" (transformer) and boost the signal strength going to the power booster. This has nothing to do with the output amperage of the booster.
In my previous scenario of having to add an additional power booster- -to facilitate more locomotives- -it can be done, with some caveats.
Adding another 5 amp booster would satisfy the locomotive's need for extra power.
However, 10 amps of power running down the tracks might be a little risky. That's about the power of the average AC socket in your home!
To safely distribute 10 amps over the entire pike circuit breakers and "power districts" are typically employed.
Power districts are electrically isolated sections of track controlled by a single circuit breaker.
Each 5 amp power booster's output can be broken up into smaller blocks- -similar to DC operation, similar to the breaker panel in houses.
The input to the circuit breaker panel in most homes might be 100 amps, with a "main" breaker. From there the power (amps) are broken down into lower-rated breakers (for most domestic applications this is 15 to 20 amp, single phase, circuit breakers).
To answer your question...
Boosters are rated in amperage output.
This is the potential to run "X" number of locomotives based on the total amperage draw.
Signal strength is dependent on how far the signal has to travel from the signal generator (throttle) to the command station/booster.
I have only discussed a wired situation, this does not include any "wireless" systems; Infrared, WI-FI or radio-based.
A resource that you can add to your model railroading library is "The Digitrax Big Book Of DCC". Despite being published in the late 1990s, the concepts of DCC have not changed over the years.
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
I have an NCE Power Cab and a few years ago I ran too many sound locos (a couple of double headers on a 4x6 layout and fried the works. They quickly repaired it, but advised me not to run more than three. Of course more powerful systems can run more without an added booster. At the time, pricewise, it was better for me to buy the Power Cab and a booster when I built a larger layout(hopefully before summer).
Have fun,
Richard
Best answer? It depends.
My main layout uses a procab and I'll run 2 trains on the mainline, one on each of two branch lines, and a Switcher in the yard. In total that is 9 or 10 dcc and sound locomotives and it all works without a booster. However, I use newer locos with low draws, so no problem.
My small layout uses a PowerCab. The layout only has enough space to let one train run in circles and one Switcher in the industrial sector, so no problem there. I have used a PowerCab to run 5 sound locos at once. No problem
There are several 'more complete' answers listed above so all this post contains is my personal experience.
JJF
Prototypically modeling the Great Northern in Minnesota with just a hint of freelancing.
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Tomorrow is a Mystery.
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jjdamnitWith DCC the thing to keep in mind is technically there are two (2) components to it; signal packets and power.
With DCC, the power and signal packet are one in the same. Unlike some early digital and analog control systems that had a separate weak signal superimposed on the power, the DCC signal is the full amplitude of the power - if you're getting power you're getting the DCC signal.
jjdamnitThat's why with DCC there are standalone command stations- -throttles (signal packet only), combination command stations and power sources (signal packet and power), and booster stations (power only).
Throttles are not command stations. A DCC layout can only have one command station (genreally speaking, there are tricks you can use to have more than one, but they have to be electrically isolated at all times, basiically really seperate layouts). The command station receives input from the throttles and generates the DCC packets for the layout.
jjdamnitAdding another 5 amp booster would satisfy the locomotive's need for extra power. However, 10 amps of power running down the tracks might be a little risky.
If you add a 5 amp booster, you will not have a potential of 10 amps running down the tracks, you would have two seperate districts each with an available 5 amps. You don't "gang" the boosters, you have them powering seperate areas of track. If you really need 10 amps in one section, you use a 10 amp booster, not two 5 amp ones.
jjdamnitThat's about the power of the average AC socket in your home!
Actually, power is watts = volts x amps. A 10 amp 120 volt circuit will have 10 times the power of a 10 amp 12 volt circuit.
When calculating the number of locomotives, does that mean the number of locos actually operating at one time, or are idle locos also counted in total power consumption? Once I finish repowering perhaps a dozen locos will be sitting on the layout, but most will not be moving, generally just one or two operating at any one time. My original DC plan used power-routing Insulfrog turnouts, so most of my motive power in the yard isn't connected to power when not in use, but I'm planning on rewiring so all track will be live, as I have had issues with Insulfrog's power tabs getting weak or dirty over time, resulting in dead track sections unless I add more feeders. Will the engines in the yard count against the 5 amps my command station/booster produces?
Regarding length of run, currently I have about 60 feet of mainline (11x24 foot layout room), and my command station/booster is about 3/4 of the way down the track, roughly 15 feet from one end. I've seen some articles mention that you shouldn't have a run of more than 30 or so feet without a separate power district, so I'm considering moving the command station to the middle of the layout (fortunately it's right next to an AC outlet) so my main power bus will run no more than about 30 feet in each direction. I'm preparing to rewire the main power bus for the whole layout (currently 18 gauge bus to provide feeders every 3-5 feet, designed for DC with no block control) to 12 gauge feeders, but still debating over whether I need the complexity of dividing it up into multiple power districts (although I'll need at least one for a reversing wye.)
So I'm interested in the OP's topic of discussion; if I really need multiple power districts on a medium sized layout, that means running a lot more wire (a main power bus, then separate buses to each power district), right? It will be enough of a project to rewire it once--I don't want to do it twice unless it's necessary!
JetrockWhen calculating the number of locomotives, does that mean the number of locos actually operating at one time, or are idle locos also counted in total power consumption? Once I finish repowering perhaps a dozen locos will be sitting on the layout, but most will not be moving, generally just one or two operating at any one time. My original DC plan used power-routing Insulfrog turnouts, so most of my motive power in the yard isn't connected to power when not in use, but I'm planning on rewiring so all track will be live, as I have had issues with Insulfrog's power tabs getting weak or dirty over time, resulting in dead track sections unless I add more feeders. Will the engines in the yard count against the 5 amps my command station/booster produces?
Anything drawing power from the track is going to add to the total current draw and needs to be considered. Even a loco sitting on the track, no lights on and no sound, is going to draw some current to run the decoder's processor. If it has lights on, that's a little more current and if it has sound on, even more. That being said, they are not going to draw near as much as running locos, so a dozen or so shouldn't be an issue. One thing you can run into, however, if you have a lot of sound locos is some of them draw excess current when powered up so that could be a problem even if the operating current draw is well within your booster's capacity.
JetrockRegarding length of run, currently I have about 60 feet of mainline (11x24 foot layout room), and my command station/booster is about 3/4 of the way down the track, roughly 15 feet from one end. I've seen some articles mention that you shouldn't have a run of more than 30 or so feet without a separate power district, so I'm considering moving the command station to the middle of the layout (fortunately it's right next to an AC outlet) so my main power bus will run no more than about 30 feet in each direction.
30 feet shouldn't be a problem. Digitrax recommends 50 feet between boosters, so a 25 foot run in each direction, but they also mention that it's a very conservative value.
JetrockSo I'm interested in the OP's topic of discussion; if I really need multiple power districts on a medium sized layout, that means running a lot more wire (a main power bus, then separate buses to each power district), right? It will be enough of a project to rewire it once--I don't want to do it twice unless it's necessary!
The only additional wiring would be the command bus from the command station to any additional boosters, the layout it self wouldn't be wired any different, other than having the power bus split and the districts isolated from each other at the rails. I would just wire it as if you are going to have power districts and then join the buses together, that way if you ever decide to add a booster it's a lot simpler. For example, split the layout in half with a seperate power bus running along each half (and the rails isolated at the split) and join the two power buses at the command station. If you later decide to add a booster, split the buses and move the command station to the center of one and add the booster to the center of the other.
Jetrock When calculating the number of locomotives, does that mean the number of locos actually operating at one time, or are idle locos also counted in total power consumption? Once I finish repowering perhaps a dozen locos will be sitting on the layout, but most will not be moving, generally just one or two operating at any one time.
When calculating the number of locomotives, does that mean the number of locos actually operating at one time, or are idle locos also counted in total power consumption? Once I finish repowering perhaps a dozen locos will be sitting on the layout, but most will not be moving, generally just one or two operating at any one time.
I had wondered about this at one time and researched the Loksound decoders. What I found was that for just the decoder sitting on the track with sound on the current draw was approximately 0.02 amps. Lights are extra.
My conclusion was that with a 5 amp power supply I didn't need to worry about even 20 locomotives sitting on sidings from a power issue. Keeping them quite is another issue so I installed SPST switches on each track in the main yard.
Rick
Engines and accessories, if you plan to feed them from your track power.
I agree with CSX Robert, I'd split the layout into two districts (probably upper and lower, if you're going double-deck), get the track in place, and try it out. If it turns out you need a second booster, it will be easy to do.
In my case, I don't run many engines at once or anything, but my layout is fairly spread out - basically a shelf layout around three walls of a good-sized basement. I found I could operate the layout with just the power from the DCC main controller located in the middle, but engines slowed noticeably at the far ends, so I added a booster on each side. May be overkill, but I'd rather have too much than not enough.
There are a lot of very good comments in the replies that precede this reply of mine.
As others have pointed out, a single 5 amp booster is usually sufficient for an HO scale layout, particularly when the layout is a home layout with few operators. The key factor in deciding whether to use a second 5 amp booster is the number of locomotives being run at any one time and whether some or all have sound decoders. The other reason for a second booster is to counter the issue of voltage drop if that is a problem on a layout.
I agree with the suggestion to create power districts in order to balance the current being controlled by a 5 amp booster. The use of power districts better identifies where the current consumption is greatest rather than relying on the booster alone.
I have a fairly large layout at home, 42' x 25', and for years I relied solely on a single 5 amp booster and no power districts. However, in recent years, I began to divide my layout into separate power districts.
On my current layout, I have 7 power districts, four of which are reversing sections. I decide to use a second 5 amp booster to provide current to the four reversing sections just so that I better balanced the power distribution.
Did I need a second 5 amp booster? No, not really, but it gives me better peace of mind. Do you need a second 5 amp booster? Probably not. You will know if you need a second booster if shutdowns become frequent or if voltage drop becomes an unresolved issue.
Rich
Alton Junction
I need to add a booster!