Will 100W Be Enough?

[Sir TophamHatt]

Will a 100w power supply be enough to run a bunch of lights on platforms, buildings, signals?

[Oldddudders]

Watts = volts x amps, I believe. So if your supply is, say, 12v, then that is 8.5 amps, which is massive. If your lights are LEDs, and so are the signal aspects, I suspect you could run many hundreds at once. 

[HLT 0109]

9 hours ago, Oldddudders said:

Watts = volts x amps, I believe. So if your supply is, say, 12v, then that is 8.5 amps, which is massive. If your lights are LEDs, and so are the signal aspects, I suspect you could run many hundreds at once. 

 

. . . but, if using the incandescent, grain of wheat/rice bulbs, allow 1 watt per bulb, which will limit you to 100 bulbs.

[DCB]

I wouldn't risk any more than about 12 watts  or 12VA per circuit.  I'm a bit paranoid about starting fires after my next door neighbours house burned down.  If you have to use a 100 watt supply fit some overload protection as in polyswitches.  I wouldn't use more than 5 volts for lights so that would be a 20 amp supply for 100 watts.

[Sir TophamHatt]

5 hours ago, DavidCBroad said:

I wouldn't risk any more than about 12 watts  or 12VA per circuit.

 

It's okay, the PSU converts the power to 12v DC for the actual circuit. I could have chosen a smaller unit, say 60W but too late as it's on it's way now though.

 

This is the link to what I've purchased: https://www.ebay.co.uk/itm/254252328250

 

Has been a little inspired by this video:

 

 

Where, in theory, I could have a few different 12v circuits all coming from the one PSU. Although the person in the video plans to use the other voltages too.

Edited July 14, 2020 by Sir TophamHatt

[Dagworth]

1 hour ago, Sir TophamHatt said:

 

It's okay, the PSU converts the power to 12v DC for the actual circuit. I could have chosen a smaller unit, say 60W but too late as it's on it's way now though.

 

This is the link to what I've purchased: https://www.ebay.co.uk/itm/254252328250

 

Has been a little inspired by this video:

 

 

Where, in theory, I could have a few different 12v circuits all coming from the one PSU. Although the person in the video plans to use the other voltages too.

The unit you have purchased MUST be put in an enclosure and not just on a board as in the video as the mains input connections are only screw terminals.

 

Andi

[DCB]

 

3 hours ago, Dagworth said:

The unit you have purchased MUST be put in an enclosure and not just on a board as in the video as the mains input connections are only screw terminals.

 

Andi

  Agree  The one in the link with screw terminals, no sign of a fan etc really belongs securely riveted into an enclosure. Or an enclosure inside an enclosure.   Bare mains terminals can be life threatening.

The unit in the video looks like one from an old style computer tower which would have a cooling fan and a 3 pin 240 volt socket.

I have several in the loft both in towers and loose. Basically you can pick them up for free.  Screwed to a bit of wood as per the video they can be OK but don't spill your coffee over it.

 These units are OK for LEDs on 12 volt or 5 volts subject to having overload protection to protect the wiring, but they do only deliver a bare 12 volts while "12 Volt" model railway units are often around 19 volts, and 12 volts is too little for a decent top speed on most RTR OO Locos.  24 volts is too much. 

I haven't managed to find a use for any of mine yet mainly due to needing overload protection, and having plenty of old railway controllers.

[PatB]

15 hours ago, DavidCBroad said:

I'm a bit paranoid about starting fires after my next door neighbours house burned down.

 Well, if the arson squad have got their eye on you....

[Sir TophamHatt]

Hmm.

 

Will probably return the "naked" one as I'd rather not have to buy something else as well.

 

Although to be fair, it would be under the model railway in a somewhat unreachable location safe from anyone touching it.

 

But I think I'd rather be safe than sorry.

[BR60103]

7 hours ago, Sir TophamHatt said:

Although to be fair, it would be under the model railway in a somewhat unreachable location safe from anyone touching it.

 

Didn't you recently acquire a Junior Toppam Hatt?

 

[Sir TophamHatt]

16 hours ago, BR60103 said:

Didn't you recently acquire a Junior Toppam Hatt?

 

I did indeed.

 

But I should have explained better. It'd be in a gap that is less than 10cm in height, about a metre in depth, the base height is over a metre itself so pretty hard even for an adult.

 

But it will most likely live in a box as I have acquired a laptop power supply for lights, so points can stay with the Hornby controller.

[Mike Buckner]

On 15/07/2020 at 20:16, Sir TophamHatt said:

Will probably return the "naked" one

 

On what grounds?