August 1, 2013

TT #73 The ABC's of LED's in RV's - Part 3

By: Rob Lowe

Technical Tips #73 


The ABC's of LED's (Part 3)

The RV industry is moving toward the installation of LED (Light Emitting Diode) light fixtures. In some cases this involves simply equipping the existing lamp fixture with a LED bulb. In other cases, and in future designs, purpose built LED light fixtures that are a sealed unit will become the norm since the life of the LED's can be as much as 60,000 hours. More and more RVers are deciding that they want to upgrade to LED's in their coaches and trailers. There are some basic principles that are important to understand before heading in that direction. This article is the third in a series covering various facets and considerations when upgrading or switching to LED lighting. See Tech Tips #71 and 72 for the first two parts.

Rules of Thumb for LED Replacement Bulbs

The following chart gives some indication of the light characteristics for a LED replacement in a single bulb fixture. Multiple fixtures allow a reduction in the light output per bulb since in combination there will be ample light for the area. The number and size of LED's in the replacement bulbs will also determine the light pattern and brightness. Some give off light in a 120 degree angle whereas others provide 360 degree light dispersion. Selecting a specific light direction may allow a lower output bulb to provide adequate light. More LED's for a specific light output may offset the highly directional light of the LED replacement bulbs.

Light Level

Bedroom, hall areas

General Purpose, Ceiling in multiple fixtures
Individual fixtures, bathroom
Dinette, Work Areas, Small Reading
Individual Reading lights, Storage Areas
Storage, Ceiling
Large areas to be lit with low number of fixtures, or Fluorescent tube replacements

Selecting a knowledgeable supplier can greatly assist in the LED replacement process. Be prepared to buy a few bulbs that may not be suitable to you, since in the end it is your decision as to what light is sufficient. It may also make sense in some applications to replace the complete fixture with a purpose built LED fixture, mounting that fixture in a location best suited for the use. (i.e. placing the light fixture in a storage area where the light pattern properly illuminates what is stored, rather than accepting the location chosen by the RV manufacturer.)

Exterior Lights

Most of this series has been focused on replacing lighting found within the RV. The question arises "What about changing the exterior marker, taillight, brake and signal lights with LED's?" This brings a few other considerations into the mix. Exterior replacements must be similar in light output to the originals for safety. The color of the bulb must match the lens, i.e. a red replacement should be used under a red lens, an amber replacement under an amber lens and so on. It is also much more critical that the light output be dispersed similar to the original. Since the LED bulb draws much less power, signal flashers may need to be upgraded or changed to operate these low current bulbs. Ground and power connections need to be very good and kept clean since the slightest resistance to power flow can create a light that operates intermittently. The initial thought may be that the LED bulb is defective when, in fact the electrical system feeding the LED is aged and degraded. Generally speaking, unless you are prepared to work through the issues that arise from replacing the exterior bulbs, do not replace them. You will notice that newer vehicles come equipped with one piece LED light fixtures to eliminate the problems associated with replacement bulbs. Bargman, a manufacturer of many lighting fixtures found on RV's, have introduced LED lens units that replace the bulb and lens with a one piece LED replacement. This is a good alternative.

For RV Patio lights and other non-safety exterior lights, using some of the flat board style LED replacements will provide more than adequate light output with minimal reconfiguration of the light fixture to accommodate the directional nature of the replacement LED.

How to Buy: Sample then Decide

If you have made the decision to replace some or all of the interior lights in your RV, then I recommend making a list of the bulb style and number by area within the RV. This will form a basis for establishing the priority and quantity of each type of bulb you will need. Then select a few locations where you can "sample" the LED replacements. Select a few ceiling fixtures, (the ones that are on the most), a few reading lights, perhaps an often used fluorescent fixture and so on. Buy the replacements for these and install them. There is a period of adjustment while you adapt to the different light output, both amount and color and the directional nature of the light. After a period of use, you can decide to replace more on your list.

Most replacement bulbs simply require that you rotate and remove the existing bulb (#1141, #1156 type bulbs) or pull them out (#921 type bulbs). For the G4 halogen fixtures the glass plate covering the bulb rotates by pressing up on the glass evenly and rotating counterclockwise a partial turn. Rubber gloves will provide better grip. The original halogen bulb should only be removed using a rubber glove or cloth to prevent oil from your fingers collecting on the glass bulb envelope. This oil will degrade the glass such that when it is turned on again, it is possible that the bulb will shatter where the oil damaged the glass. Taking this precaution will reduce this risk.

Where to Buy

As with any improvement to a home or RV, it is helpful if the supplier has experience that you can draw upon. Price is always a consideration, although it is hard for a neophyte to understand all of the various product characteristics and issues. Some will be driven by the lowest power consumption; others will be concerned with the overall lighting effect after replacement. Others will focus on the reputation of the manufacturer and their warranty, while others will be concerned with the wide operating voltage range and ability to be able to dim the bulbs. There are lots of other characteristics that are important and all of them will be bundled up in the price paid. After sales support should also be available since invariably there will be a question or two that arises after making the conversion. We began selling LED's six years ago and tapered off after the first two because of the vast range of quality that appeared in each new batch of bulbs, and the understanding that simply replacing a bulb without understanding some of the electrical characteristics might leave unhappy customers as a result. Our product line today is demonstrably a far better and improved product that carries a warranty, and is designed to operate in a much wider range of voltage and electrical conditions than prior products. We can assist and give guidance to make the transition to LED a reality.


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