LED Light Conversion

[Dwarfer]

Hi guys, im not sure if this has been written up before but I’m sure it’s been done a few times as it’s such a good upgrade. So I wanted to change my caravan lights to LED mainly to extend my battery life as much as possible but the better light quality and reliability are a bonus.

So for the LUMO type fittings my options were to fit new led fittings, fit led conversion tubes to my fittings or to convert the fittings myself, now being a bit cheap and wanting to keep the look the same I decided to convert the fittings myself.
The LED’s I decided to use were these “12V 5 SMD 5050 LED Module Light Hard Strip Bar Light Lamp Waterproof 5 Color”



I ordered 20 of them on ebay for £3.97 from China and they arrived in about three weeks, they are quite handily already wired together so I tested them by connecting them directly to my 12v supply and they are extremely bright when 20 are shining in your face.
I wanted my LED lights to be about the same brightness as the original lights but this is a hard thing to achieve. If we are measuring in lumens then a LED light with the same lumens will appear much brighter due to the better light quality, so for DIY purpose there is little point in measuring the light output with a light meter so I just guessed that six modules would give about the right amount of light.

Remove the fitting from the ceiling, disconnected the cables and removed the cover.

Remove and disconnected the two 8W fluorescent tubes then stick the six led modules in their place using the sticky foam pads on the back.



Solder the positive cable of the led modules to the circuit board as shown in this picture (the grey wire)



This will give you the original positive cable on one side if the switch and the new led modules on the other.
The negative connection has now to be made to the led module not the circuit board so I extended the cable by a few inches
Now just replace the cover, reconnect the cables and screw the fitting back in place



The nearest light is the LED converted fitting compared to the original fluorescent to the right.

I haven’t yet found LED lamps which will fit in the little spotlights but the toilet/shower room and awning lights will take any white LED replacement car lamps .

 

[Dwarfer]

I forgot to say I measured the currant, calculated the wattage and it came out at 5.5W, if you compare this to the two 8W tubes in the original fitting plus the losses in the fitting itself which probably brings it to around 18 to 20W total it’s a very good reduction in battery load.

There is also plenty of room for more LED modules, if you cut of the little screw hole tabs you could fit 12 modules for twice the light output I have here and still a decent saving in power consumption.

 

[ProfJohnL]

Hi Dwarfer,
That's a good way of doing it, but why didn't you remove the redundant PCB behind the switch?

Just a couple of points about the light quality and intensity, conventional bulbs (fluorescent & incandescent) produce a wide spectrum of colours giving the impression of a "softer" illumination, but LEDs tend to have a much narrower band of light emmisions leading to a "harder" feel.

Conventional bulbs have a large emmisive area, giving a lower Lumens per unit area than LEDs which are by comparison almost a point source which needs a very high L/M2 to produce the same overall illumination. The way LEDs are made on a substrate means they can only emit light from one side this inherent directionality again intensifies the apperance if you look directly at them, and why it's not wise to do so closely.

The LEDs you have used directly emit light in the visible spectrum, but Philips led (excuse the pun) the development of domestic LED bulbs where they used UV LEDs inside a coated envelope, where the coating was fluorescent when exposed to the LEDs UV energy and would emit in the visible spectrum, across a wider range of visible colours, more closely mimicking the conventional incandescent bulbs we had been used to.

 

[Dwarfer]

The switch is soldered into the pcb and the switch and pcb hold eachother in place. There is also no need to remove the pcb as there is no connection to the negative side.

Light quality is a massive topic which we could go on about for days but the led's I have used here are much closer to daylight than any filiment lamp and almost any fluorescent lamp we are just used to the warm glow of filament lamps but the eye gets used to the whiter light and will probably thank you for it in the long run.

One down side is that this whiter light will be even worse for your night vision than the fluorescent or incandescent lamps. This is probably not an issue on a well lit camp site but if you intend to do any wild camping it might be. I would like to try fitting some red LED's and a three position switch so that I can switch between white and red light similar to the lights on boats.