# DC bus voltage



## RonK9977 (Oct 4, 2019)

For a DCC layout it is recommended that you run your DC accessories off a DC bus leaving the DCC bus then for the trains to have full power.

My question is what size power supply (volts and Amps) would be good for the DC bus to power the stationary switch decoders etc etc.

thanks
Ron


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## mesenteria (Oct 29, 2015)

The answer would depend on your anticipated and current needs.

You'd have to anticipate the greatest number of amps you'd ever require to service all DC components, and then supply the appropriate amperage that the voltage can provide. Maybe two or more such DC power supplies would end up being the better solution, and not just one hefty one.

It is unlikely that you'd ever want more than about 5 amps-ish, but perhaps your designs are more lofty...? What would the maximum DC voltage be for a given item, and if that is so, would a 20 volt supply be reasonable? Perhaps not.

Remember that there are decoders which need AC, and then the decoders instruct actuators of various kinds with their own inherent amperage demands, but in DC. Two, maybe three different buses, each with a dedicated power management system and supply.


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## flyboy2610 (Jan 20, 2010)

Do you have an old computer laying around?





Here's how I did mine: (Need to get that base painted and finished up.)

http://www.modelrailroadforums.com/...computer-power-supply-for-layout-power.31752/


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## DonR (Oct 18, 2012)

Ron

It would seem to me that if you are using DCC stationary
decoders to control your turnouts you would need
to have them on the DCC bus in order to get the
DCC encoded 'commands'. I have not used any of
these devices, but I understand that some stationary
decoders use the DCC current for point switching,
while others have
a decoder that switches regular DC current to move
the points.

The instructions that came with your stationary
decoders should have specifications for power
and whether they can use the DC power for the
points.

If you elect to use DC power for your points any used
standard HO power pack would provide all the
current you need. Set it for around 14 volts or so.

Don


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## RonK9977 (Oct 4, 2019)

*Decoder power*

thanks for all replies

Yes the decoders I am looking at using are digikeijs and you can supply the POWER from a DC source (recommended) and the SIGNAL from the DCC bus...they say this leaves all the power for your trains.

I downloaded the manual for the decoder but didn't see the DC voltage it needs (have to recheck) but did see the diagram showing the DC power setup...

Yes an Old PC will work or I saw these little power supplies 0-30 volts @ 5 AMPS...just dial in the voltage you want AND only 29.00!!!! Seem not too bad to me. They are small and versatile too! https://www.aliexpress.com/item/4000406474185.html

Just a thought


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## DonR (Oct 18, 2012)

Most turnout motors are designed to use
around 14 volts. 

5 amps is way more than you need for
turnout points. Regardless of the number you
have, each uses a burst of power momentarily
then goes to zero. Idle stall motor types use very
little even tho connected at all times.

You can probably find an old wall wart that
puts out 12 or so volts that would be sufficient.
If you don't have one you can likely find one
at most any flea market. Each has it's output voltage
and whether AC or DC on a label.

Don


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## CTValleyRR (Jul 26, 2014)

I run 36 Tam Valley Depot servo motors off a 60W (12VDC) wall wart that I purchased from Amazon for about $6.00.


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