DCC Analysis Paralysis

R

Rhyph

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So, I know I'm relatively new around here, but I'm not really new to the hobby. I am also pretty new to DCC, and have a fully functional DCC Digitrax system on my indoor HO scale layout. I also have a DC G scale outdoor layout, and this is where I want to focus next on taking everything DCC.

I found a really good deal (at least I think so) on a brand new NCE PH-10R which I've seen mentioned and generally recommended here on the forums on a few occasions, including on elmassian.com ;)

Then I broke my brain. :drunk:

Power supplies have me very confused at the moment, and this is where I need some guidance. I guess NCE says you need to use the "Brutus" power supply. But it's 18VAC? Isn't that too low for G scale? I thought everything was supposed to be DC? Then I see reports of using other power supplies that are 12-24v DC, and various amperages, and I'm getting lost and confused. I know that HO is fine with the lower voltages, and that our big G scale layouts really need 20v+, correct? Would a power supply like this on Amazon work with the PH-10R?

I guess at the end of the day, I'm trying to put together a best bang for the buck DCC system when accounting for layout size, power supplies, boosters, etc. I've looked over Piko, Massoth and Zimo and in order of increasing costs and understanding their own limitations, I sorta concluded that NCE was the most capable until you hit Zimo (maybe?) but I don't have that kind of budget.

Halp! And thanks in advance for your wisdom! :D
 
18v AC, full-wave rectified, gives 18 x 1.414 or about 24volts after a bit of smoothing.. :)

So fear-not, young Grass-Hopper! You will fulfil the potential required. :nod::nod:
 
They have never "gotten" G scale, a simple transformer will have it's voltage go up and down with load. Luckily the NCE system will accept regulated DC, buy an inexpensive Meanwell transformer. Also note that the track voltage will be 3 volts less than your DC input to the booster.

The regulated supply will perform better and more consistently, and the 18v ac unit will be a little low, you should try for about 24v DCC, but you will get about 22.

read this:

NCE Mods & Tips

Greg Elmassian web site on large scale trains and garden railroads, cigars, and computers
elmassian.com elmassian.com

When I started outdoor G scale DCC, the common wisdom was just a transformer, now everyone uses a regulated DC switching supply.

please also read this:

My implementation

Greg Elmassian web site on large scale trains and garden railroads, cigars, and computers
elmassian.com elmassian.com

You will thank me later... no idea why NCE has not upgraded their thinking on almost 20 years, great product though.

powerstack.jpg
 
Yes, thanks Greg! That's exactly the reinforcement I was hoping to hear and even after I've crawled all over your site, I think I'm going to pull the trigger on exactly that set-up.

Can you add more boosters down the line later when needed? Would you suggest adding NCE or Tam Valley boosters?

And on edit: Would the meanwell power supply I linked above from Amazon work?
 
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As an aside..
I use a Digitrax on my programming track. - The lower voltage being 'more forgiving' if you forget to set a voltage divider, amongst other things.

I have never 'popped' anything using this.. :)
 
Yes that supply will work, but I would recommend a 27 volt one since the 24 volt one will result in a maximum of 21 volts output, and in G scale, there are good reasons to try to get to 24 volts at the track. Reading my articles you will find about that voltage loss through the booster and tricks for getting the most voltage from the booster.

On the boosters, I would buy the NCE for sure... first, the Tam Valley unit is nice, but only 5 amps vs 10 amps, and is not "smart"

NCE provides a "bus" to add more boosters, and on that bus, the system will send commands to shut down the booster from your remote, by pressing the red button on your throttle. You cannot do this with other boosters that do not have this "bus interface"... trust me, being able to use the 3 level emergency stop, and the third level disconnects power, is a great feature, when a loco derails on a switch, and 10 amps is trying to melt the internals of your loco, being to remotely and immediately remove power is worth it's weight in gold (or at least replacement loco parts)

There are several other advantages, but these are big enough to make the decision a no-brainer.

Greg
 
Greg Elmassian said:
Yes that supply will work, but I would recommend a 27 volt one since the 24 volt one will result in a maximum of 21 volts output, and in G scale, there are good reasons to try to get to 24 volts at the track. Reading my articles you will find about that voltage loss through the booster and tricks for getting the most voltage from the booster.

On the boosters, I would buy the NCE for sure... first, the Tam Valley unit is nice, but only 5 amps vs 10 amps, and is not "smart"

NCE provides a "bus" to add more boosters, and on that bus, the system will send commands to shut down the booster from your remote, by pressing the red button on your throttle. You cannot do this with other boosters that do not have this "bus interface"... trust me, being able to use the 3 level emergency stop, and the third level disconnects power, is a great feature, when a loco derails on a switch, and 10 amps is trying to melt the internals of your loco, being to remotely and immediately remove power is worth it's weight in gold (or at least replacement loco parts)

There are several other advantages, but these are big enough to make the decision a no-brainer.

Greg
Click to expand...

Yup, I really enjoyed reading your write-ups, super helpful and informative. On the 27v power supply, you mentioned having to send your booster to NCE for modification, is that still the case or have they enabled using the 27v standard now? Sorry if I missed this detail somewhere. I also read about the adjustment to the output voltage, that part seems easy enough.

Totally agree on the reason to stick with NCE boosters on their bus system, much like my HO Digitrax system I've stuck with their equipment for similar reasons to make sure the system operates, safely, as designed. No need to have loco meltdowns! :D
 
350 -Mean Well 24v Single Output Switching Power Supply is the ideal unit to use. i use this with my Massoth DCC, being a switch mode Power supply it will adjust to input and output fluctuations automatically. Just be mindful of cheap imports. I set my track voltage to 22v output from my massoth unit and find 7 Amp sufficient for running my 6 loco LGB railway . As an example I only use 8-10 Amps on my 5 inch Loco pulling 4 Adults.
 
Railway42 said:
350 -Mean Well 24v Single Output Switching Power Supply is the ideal unit to use. i use this with my Massoth DCC, being a switch mode Power supply it will adjust to input and output fluctuations automatically. Just be mindful of cheap imports. I set my track voltage to 22v output from my massoth unit and find 7 Amp sufficient for running my 6 loco LGB railway . As an example I only use 8-10 Amps on my 5 inch Loco pulling 4 Adults.
Click to expand...

Yeah I am going to stick with Mean Well for sure as it's a good, reliable, known product in the power supply space. It's all I use for doing things like LED driver needs, etc for other various projects I have going. :D

Pending Greg's answer about the 27v question I had above, I also figured going with something like the slightly higher amps shouldn't hurt anything and just give it some breathing room under load?
 
I have no doubts on any of the above for the conditions described.
However I advise the following in the case of my local GSS group's portable layout with tightish curves about four foot above the floor and a wide range of locos.
"According to some normally reliable sources some Bachmann supplied decoders have a lower than G scale norm maximum voltage. I think 18V from a Crest supply should give a sensible maximum speed for any loco on the group’s layout whilst minimising risk of damage to members’ locos."
"
 
The 3 volt drop through the NCE is noticeable in top speed, and and it is especially noticeable in the Aristo 3 axle diesels. The output voltage on the NCE is adjustable. The 27 volt supply is a better match. 24 volts will not give full voltage.

Please remember the OP is in the USA, and yes some Soundtraxx decoders have issues over 20 volts, but this can be dealt with differently, as opposed to limiting the prototype speed.

As an example, my Aristo E8, a passenger loco, would only go 62 smph max on the level at 20 volts at the rails. 23.7 volts yielded over 90 smph. Motors are nonlinear in terms of rpm vs voltage.

We tend to run more American prototypes and larger locos here, he can always turn the voltage down at the booster too. 18 volts is unacceptable with Aristo locos since it yields 15 volts DCC... 1 volt lower than recommended for O scale.

Please read the section on Voltage on the following page for real world experience with Aristo diesels and NCE

My implementation

Greg Elmassian web site on large scale trains and garden railroads, cigars, and computers
elmassian.com elmassian.com


Greg
 
Greg Elmassian said:
The 3 volt drop through the NCE is noticeable in top speed, and and it is especially noticeable in the Aristo 3 axle diesels. The output voltage on the NCE is adjustable. The 27 volt supply is a better match. 24 volts will not give full voltage.

Please remember the OP is in the USA, and yes some Soundtraxx decoders have issues over 20 volts, but this can be dealt with differently, as opposed to limiting the prototype speed.

As an example, my Aristo E8, a passenger loco, would only go 62 smph max on the level at 20 volts at the rails. 23.7 volts yielded over 90 smph. Motors are nonlinear in terms of rpm vs voltage.

We tend to run more American prototypes and larger locos here, he can always turn the voltage down at the booster too. 18 volts is unacceptable with Aristo locos since it yields 15 volts DCC... 1 volt lower than recommended for O scale.

Please read the section on Voltage on the following page for real world experience with Aristo diesels and NCE

My implementation

Greg Elmassian web site on large scale trains and garden railroads, cigars, and computers
elmassian.com elmassian.com


Greg
Click to expand...


Absolutely right, Greg. Even indoors on a very "limited" size layout I use DC that measures 21.7 volts with less than 50mv ripple. Smaller LGB 0-4-0 locomotives will run like a DeLorean ought to, but that what speed CV's are for. Larger trains with multiple engines and passenger cars that have incandescent lighting and (intentional) smoke need that much voltage to get reasonable express streamliner speeds.
---Hutch
 
While the Zimo is an expensive system, the new unit coming out (MX10EC) is just like the MX10 in that you use a 30 volt DC supply for input power and get 24 volts DCC out to the track.
Also the Zimo has lots of control, current and voltage adjustments and when in programming mode it automatically goes to 14 volts and limits the current.
THe MX 10 is great for people needing lots of power as it is only one power supply and one command station and you get 20 amps with out any booster, plus you can add another MX10/power supply to get an additional 20 amps.
 
I have not seen the pricing on the MX10EC, but I would guess it's still a lot more than the PH10R NCE system.

I have both, by the way, the NCE and the Zimo. I needed the full 24 volts to the rails and the higher current, so while I started with the NCE, and it is still one of my favorites, I have "graduated" to the Zimo.

Greg
 
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