Alternative Power Supply for Hornby Maglights

[81F]

I would like to fit a strip of Maglights into a Camping Coach that I have converted from a Hornby/Triang short clerestory. Sadly having made an interior for it there is no room for the battery holder. As a result I am looking for alternative ways of powering the lights.

Having given this some thought I was considering wiring them into the DCC bus via a basic DCC decoder or using a specific DC Supply to replace the the battery. I therefore have a couple of questions regarding what I need to purchese.

1. For the DCC option, I have seen some decoders designed to operate lights but cannot remember what they are called.
2. For the DC option (which is probably relevant to the DCC option) what voltage do the LEDs operate on. Also would using a non-rectified AC transformer work (notwithstanding possible flickering)?

I should also add that if this coach will only need its lights when parked in its siding acting as a camping coach so there is no need for pickups from the rail (I would probably use a small plug).

Any suggestions would be helpful including any alternative battery pack combination but this would need to be no larger than 8x8x20mm.

Many thanks for any suggestions.

[LTSR_NSE]

@81F - just to rule out the simplest option first, you don’t wish to consider attaching the battery holder to the underside of the chassis?

[What About The Bee]

The battery holder holds a CR2032 battery. The CR2032 battery has a voltage of 3 volts and a capacity of up to 240mAh, manufactuer dependent. Almost any 3 volt transformer you purchase will supply that. Probably have to look long and hard to find one that could not.

I think of your camper as a static building. Just power it from the wall. No need to ever fiddle with batteries again.

Bee

[ntpntpntp]

So this is a stationary coach and you just want to light it up, with no need for DCC control or anything complex?

Just power it from a 3V DC supply. That could be something you buy specifically, or could be powered from your train controller's accessory output via a rectifier and voltage regulator such as the little module in this ebay link

AC/DC 5-35V to 3.3V 5V 9V 12V 24V Buck Step Down Converter Volt Linear Regulator | eBay

I have an N gauge coach which is a static model parked up in my steam museum, with lights on and a model railway inside! One end of the coach has a miniature plug which fits a socket mounted under the buffer stop, so the coach can be removed if something else needs to park there! It's actually powered from a 9V supply already installed under the baseboard, with an additional resistor which you can see (painted black) on the photo of the underside of the coach.

[ntpntpntp]

While my post with photos awaits approval, just to add....

"Raw" LEDs run on DC at anything from 2V to 5V ish depending mainly on the colour, and it's important that a resistor is used to limit the current or the LEDs will have a short life and/or fail. The Maglight strip is presumably just a group of white LEDs (nominally 3V ish) running in parallel from the battery. You can buy such strips of LEDs by the metre, often wired to take 12V DC and they can be cut into sub-groups :) I used a bunch of them for the roof lighting in a modern loco shed.

Powering LEDs from AC can be done but they do flicker. It's usually recommend that an inverse-parallel normal diode be fitted to protect the LEDs from the reverse half of the AC cycle.

Using a DCC decoder (use a function decoder not a mobile decoder as used in a loco) would be overkill unless you wanted to turn the lights off by DCC address and function key. Also the function decoder would probably output at somewhere near your DCC bus voltage unless programmed to reduce its output.

[P-Henny]

If the coach is going to be static. I would use a DC - DC BUCK Converter - a couple of quid on ebay.

If prepared to wait for ebay Chinese delivery, they can be bought for less than the example one linked below.

These converters can take a wide range of DC Inputs and are adjustable for their DC Voltage output. For example 3 volts to substitute the CR2032. They have a LED Display showing input and output voltages. Being adjustable, you can also use it to adjust light brightness if you adjust voltage below 3 volts.

Example BUCK.

https://www.ebay.co.uk/itm/166046676818

If using with DCC track voltage, you would need to run the DCC track voltage through a Bridge Rectifier first to generate DC for the BUCK Converter input.

EDIT: When I posted my BUCK converter reply, triple ntp's BUCK link post wasn't visible, as it was awaiting approval.

[81F]

Many thanks to you all. I like ntpntpntp's solution and might go for a variation on this. Also I amn now thinking as the lights would not be on when unplugged, the use of a Magight is probably a bit of a waste and using an ordinary strip or even grain of wheat bulbs might be a more cost effective solution.

This should also allow me to tow the coach away, either on a fictitious journey to be serviced or when I have an operating session outside the Camp Coaches era.