Average Power Consumption

[WIMorrison]

Just been chatting about power consumption for a proposed layout where I was asked if boosters would be needed and it occurred that my fag packet figures may be out of date with some of the fancy new sound chips and locos that have double digit functions.

 

Any suggestions on what an average loco with,/without sound/light will consume for planning purposes in 00 scale or N?

[WIMorrison]

I have found these figures in an old post here (apologies to original author as I cant find the link again )

 

• (full power) Loco with sound and 8 coaches with 3 LED per coach= 0.49 amp (loco 0.25+0.24 for lights)
• (full power) Loco with sound and 10 coaches with 3 LED per coach= 0.55 amp (loco 0.25+0.3 for lights)
• (full power) Loco with sound and 16 coaches with lights with 3 LEDs each= 0.73 amp (loco 0.25+0.48 for lights)
• Operating goods loco with sound and brake tail and interior light - 0.27 amp

it looks like he has based it on 10mA (0.01a) per LED and 250mA for each loco.

 

Are there any views on this as they seem a tad low to my memory. This does seem to be a question that is asked quite often going by a Google search, though there isn't any definitive answer that I can find which is strange as it begs the question of how people design a layout. It is a bit late to have built the layout and find that it needs more power and you then have to rewire to include boosters.

[Phil S]

Modern locos using LEDs consume less than an older loco with a single bulb !  Simply adding further sound functions would have no effect - but perhaps the volume at which you play them would 8-)

 

All I can really suggest is to use Rrampmeters to monitor, as I do - although many modern controllers such a the Z21 include current draw.  (As did the ZTC 511 and MultiCentralePro > Multimaus Pro)

 

It was the current display on a ZTC511 - showing a steady 3.5A that led me to discover a faulty fleischmann point in which the frog switching had failed ... melting the plastic even more 8-) .

 

Because I originally planned my loft layout for a ZTC511 (as the 'compatible change' from Zero-1) _ I was originally basing it on 2 x 5A districts (511+1 booster) - but because the Roco Multimaus had so many advantages (and kept coming 'free' with the digital start sets I was buying) ... it became a Roco-based layout using 3.2A Amplifiers (and SMPS supplies of 3.5A-4A each - all Trust Pilot Computer supplies at the time  (I initially chose models with variable voltage before settling on the Rooc advocated 18Vdc > 16Vdcc on track)  

 

With RRampeters (and PSXs) on each of the 4 Power districts, and using Roco Digital (Rocoline) point motors or analogue Roco via LS150s with separate power supply, I have NO SUDDEN requirements for bursts of switching power.

 

(Anyone using enrgy-ineffiicent Peco Solenoid type motors from their dcc bus, and not via a CDU, will need to consider using 1 bus/Power District  just for them, so as not to cause brown-outs elsewhere ... which is immediatley obvious with Sound-fitted locos anywhere on the layout !!)

 

Whilst I have many sound locos (but not as many as on our H0 or LGB portable layouts  which work off a SINGLE Roco Amplifier ( the garden LGB has gradients, and uses 2-5A of its 8A Massoth Dimax output ), it is COACH LIGHTING (and older bulb-basd colour-light signalling if run from the dcc busses, and not a power supply) which is the main contributor to the quiescent current in the loft...

 

Typically 0.25A for 3 districts, and just over the 1A for the storage area  (due to the imbalance of the changeover from ZTC to Roco - in which the scenic area was split into 3 power districts, but the lower level storge area is 3 sub-districts)

 

That current is mainly from 6 rakes of 5-6 coaches lit with LEDs.   A running loco (not an X04 !) is typically less than 0.5A ... and - this is where 'size of layout' becomes irrelevent -  as a model of North Devon - it has 4-5 routes from Barnstaple, on which only 1 train can practically be moving at any one time (especially with 1 operator).   As a train runs round, I can follow its 'extra current' as it passes from Rrampmeter to RRampmeter.  ( I believe in diagnostics - I used to teach maintenance of broadcast TV equipement).

 

I am nowhere near using the full load of each Amplifer/power supply - in the loft - and can actually switch my dcc distribution to use only the master - saving energy by not using the other 3 power supplies ... but smps are quire effiicent compared to old transformers - so ths is not an issue - but a diagnoistic convenience.

On the multi-level H0 layout - the incline /helix connecting levels is usually used with only 1 or 2 trains running, otherwise with 3-4 they are on the level.. and all operate within the limits of 1 controller. 

 

SUB -Sections are the most important 'inclusion' on a dcc layout - to be able to isolate and identify a faulty area rapidly - and without affecting runningnin other areas .... the need for multiple POWER-districts  is probably highly-overated, in my experence !!

 

(Back in Zero-1 days, the '4 train (current) limit' was also dependent on which direction they were running - because the decoders did NOT use full-wave rectification - but only took 'power' during their direction's time slot .... with faster locos turning on earlier, and all, in one direction, on at the end (14 speed steps = 14 start times in that direction's 50Hz power pulse.)   With full-wave rectification, dcc decoders (and ZTC's zero-1 decoders) take their power at 'random' (indpenedent)  times - evening out the power demand.

SOUND decoders will also be even-demand takers, via their smooting capacitors, as will full-wave rectified lighting ...

 

By comparison, the H0 layout is running near its maximum for 1 dcc power supply (and the 12Vdc LED layout lighting is at its limit of 6A... splitting to 2 x 6A later this year 8-), and the 17m of LGB, on flat or sloping ground runs 1 or 2 locos okay BUT when the multi-motored Allegra 3 car EMU hits a buffer stop ... it trips the 3A limit !

[WIMorrison]

Back to my simplistic question which only needs a simple answer

What power consumption or current draw should be assumed for planning purposes?

[Phil S]

'A simple answer' = 1/4 Amp  for 1 narrow gauge commerical build loco - but may mislead as you asked about "an average loco with,/without sound/light will consume for planning purposes in 00 scale or N?"

From my post you will find examples to work from - which take into account the current taken by Accessory decoders **  and signalling, as well as sound and lighting    ... but how long is a piece of string.  It all depends on how much stock is parked on your layout - and how much may be moving at one time.  NARROW GAUGE layouts freuquently involve GRADIENTS and simple trigonometry /physics allows you to see how much extra power would be needed to haul trains (of what length and weight?) up those gradients.

**If your accessory decoders are separately powered, then the type of point motor is less relevent - but  there will still be SOME loading on the dcc bus .... which adds up on larger layouts.

If you add in coach lighting - if not Train Tech battery modules, for example, I gave example figures.

On our portable layouts, we try to mimimise the number of power supplies required - and to control everything via the Multimaus/dcc ...  so some street lighting is also on the dcc bus - others on the other (12V bus .. which is now at 6A)

[RAF96]

Adopt the decoder spec max rating for each loco times number of locos plus assumed loads for any ‘powered’ trailing stock plus calculated accumulative loads for any board lighting, points, signals, etc.

 

If you assume max rated loads rather max operating loads then you can base your power supply rating on max possible limits and normal day to day running will be within those limits.

 

Edit - of course if your points, lights, etc are on a separately powered bus then amend the calcs to suit.

 

Rob

Edited February 1, 2019 by RAFHAAA96

[Alan Kettlewell]

My simple 'rule of thumb' method for planning purposes is 0.5 amps per loco - that is for HO/OO scale.  With modern locos this is usually a bit more than required and therefore makes allowance for coach lights, sound on etc. 

I'd re-think and increase this if I was running older locos such as Wren with old less efficient motors.  I'd also add a bit if I was to plan a lot of accessories on to the track bus - but as I have accessories on a separate power supply, and I run modern locos, half an amp per loco has always worked for me as a rough guide.

I did some measuring using the Z21 App a while ago, where I saw most locos consumed around an average of 0.25 amps, so there's a fair bit to spare if you use 0.5 amps as a rough guide.

I hope this helps.

Cheers .. .Alan

 

 

 

[Vecchio]

Even the new Dapol 7mm locos are in the 0.5A community. (as long as the gears are not jamming... )

[NIK]

Hi,

 

For the five dozen OO loco types (all with sound off) I've tested so far it is extremely variable - from 0.15 Amps @12V DC to 0.88 Amps @12V DC - all post 2000 CE designs.

 

Heljan diesels tended to be thirsty as were Hornby diesel locos to a lesser extent.

 

Regards

 

Nick