48 volt direct current (48VDC) lighting has been slowly and quietly growing as a trend, over the past 5-10 years. Here are some important things to know.

ORIGINS

48VDC power systems originated in the telecommunications industry. Telecom needed efficiency, resiliency during grid outages, and increased safety from shock. The telecom industry invested in the first ecosystem of 48VDC components, power supplies and cabling.

Subsequently, the IT industry adopted 48VDC power architectures for cloud computing and high performance data centers. IT needed the battery backup systems that operate on 48VDC. When the IT industry adopted 48VDC, it directly led to the PoE movement, and eventually, PoE lighting, which is between 44 and 57VDC, but typically at 48VDC.

BENEFITS

There are a number of electrical advantages in going to 48VDC rather than 12 or 24VDC:

+ 48VDC reduces I²R losses by 16X compared to 12VDC, which translates to higher efficiency,

+ reduced diode voltage drops relative to system voltage in 48VDC compared to 12VDC,

+ lower currents in 48VDC vs. 12VDC,

+ reduced LED forward voltage drop relative to system voltage, and

+ it’s easier and lower cost to convert 120-277VAC input to 48VDC than 12VDC.

Removing the entire driver (or at least the AC to DC conversion) from every track head (luminaire) significantly reduces size and weight of the luminaires. This allows many of the track heads to now be magnetically attached, rather than legacy track mechanical mounting (i.e. H, J, and L style tracks & heads). The magnetic attachment then enables fast and easy, tool-free positioning and repositioning, as needed.

Today, 48VDC building microgrids are part of the growing trend toward on-site renewable energy generation, including solar panels and battery storage. There are also major safety advantages in 48VDC compared with 120-277VAC line voltage.

48VDC also became a good fit for chip-on-board (COB) LED emitters. Zhaga Book 12 defined COB LED holders and arrays, helping to standardize COB footprints and LED holders. The empty space under a Zhaga-compliant COB holder offered an ideal location to integrate a compact DC/DC driver. The resulting integrated driver COB holders helped accelerate smaller 48VDC track luminaires.

EXAMPLES

Currently, the most common application of 48VDC lighting is track, rail, and power busway systems. Some examples include:

+ Verozza Lighting’s Moduline system, pictured above and below.

+ WAC Lighting’s STRUT system.

+ Bruck’s SMARTrack system.

+ ERCO’s Minirail track system.

+ Lucent’s Low Voltage Track system.

+ Targetti’s FORTYEIGHT Track system.

+ FLOS’s Infra-Structure system.

The automotive industry has also been adopting 48VDC in vehicles, as the market for electric vehicles and their powerful batteries grows. There are now LED tapes, strips, and rope lights for 48VDC, with many of these developed for automotive and other vehicle lighting applications. Similarly, there are 48VDC spot and bar lights intended for vehicle mounting.

Are there other important aspects of 48VDC lighting that haven’t been mentioned here? Please share in the comment section below.

All Images: Verozza.com

David Shiller

David Shiller is the Publisher of LightNOW, and President of Lighting Solution Development, a North American consulting firm providing business development services to advanced lighting manufacturers. The ALA awarded David the Pillar of the Industry Award. David has co-chaired ALA’s Engineering Committee since 2010. David established MaxLite’s OEM component sales into a multi-million dollar division. He invented GU24 lamps while leading ENERGY STAR lighting programs for the US EPA. David has been published in leading lighting publications, including LD+A, enLIGHTenment Magazine, LEDs Magazine, and more.

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