Dartmouth LED lighting

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Paul Townsend
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Joined: Mon Sep 14, 2009 6:09 pm

Dartmouth LED lighting

Postby Paul Townsend » Tue Dec 07, 2021 7:46 pm

I have long planned led overhead lighting using a mix of 2 x WW and 1 x CW led strips. This combination has proved OK for several modellers and the resulting colour rendition looks acceptable to me, using Lumilfe Leds from LedHut. I have tested with white paper and several coloured objects.
The CRI was claimed to be >90 which is about the minimum to get acceptable colour rendition across the entire visible spectrum.

The 8.25M layout is to have 3 similar pelmets, each 2.75M long and comprising angle ally 50 x 25mm which carries a white PVC angle 30 x 38mm on which are mounted the led strips. The ally has the 50mm face vertical facing forward so it can carry text about the model, name etc. The PVC angle is tilted inside the ally angle so I can adjust the angle of light projection backwards and downwards.

The central section has been jury rigged for over a year and it appears satisfactory using the best led strips available in 2018. These are Lumilife 5050 size from LedHut. They are specified as 72w /5M roll which means some 38w for each of the three strings of 2.66M. Thus each 2.75 pelmet needs 3 x 38W power supply. If I want to vary the colour temperature and dim leds at dusk they need to be separately driven by 12v at 3.2Amp supplies through dimmers.
Distributing 9 x 3.2Amps at 12 v needs hefty wiring and juicy connectors and a big fat 350 watt Power Supply. I considered arranging strips in series to enable the use of 36v supplies and lighter cabling. The only source of 36v PSU at high enough amperage were either very expensive or cheapo
Chinese. I tried a latter but running it well inside its specified limit caused it to fail.

Thus I reverted to 12v distribution and have built a 360 watt PSU ( bare chassis model) inside a ventilated box and incorporated some hefty FETs and XLR connectors. The Fets will allow me to easily add dimming via an Arduino controller later. This box was built in March and is fine for the central jury rig. It has not yet supplied all 3 segments as two haven't existed yet.

My chum Dave Easto is visiting occasionally ( pre- Omicron :cry: ) to help stick down half chairs to Brook Smith soldered rivets. Once that task is complete ballasting and track painting will quickly follow, then basic scenery. Before painting starts I must have all 3 segments of overhead lighting in operation.

The led strips used before are now unavailable but I have enough to do the job. If I look at alternatives, unsurprisingly the technology has moved on and current best buys are more efficient and claim to have a higher CRI, but more expensive and some run off 24v. However they run hotter and suppliers insist on a metal heatsink mounting. I would not be able to use my PVC mounts to provide heat sinking. That probably means using angle ally tilted inside the main pelmet ally angle.

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