RV LED Upgrade

My 1990 Toyota RV LED Upgrade

In Sep 2015 I was lucky enough to get a 1990 Toyota RV with an Odyssey body, rather like a Dolphin but from a different manufacturer. Amazingly I got it from its original owner with mostly original equipment which included all-tungsten filament interior lights  throughout, about 12 altogether, mostly in pairs within light fixtures with diffusing covers, and made by a company called Progressive Dynamics..

RV Light
RV filament light- Switch in middle: Off, One light, 2 lights..
Ammeter showing draw from one 2-filament light
Volts times Amps equals Watts. You do it!
Covers Off!
Filament light exposed. I managed to buy better light-covers from Amazon, too

They do provide a warm Tungsten yellowish light as you can see but I wanted to upgrade to LED lighting to:
* save power
* improve durability
* Extend life to 100,000hrs
I already  had to replace the deep-cycle ‘House Battery”, a 12v lead-acid battery that runs the electrics which the engine alternator is not providing it, IE, when camping, and  separate from the one used to crank the engine.
The house battery  had worn out but a replacement type “22” was just $99 from Walmart. I would have put a larger capacity in but the compartment made for the original battery would accommodate nothing larger.
At that point I added an inexpensive Chinese digital ammeter/voltmeter to the mix so I could see what the draw  was upon this new battery as fixtures got used: water pump, air heater fan, fridge….
As you can see the 2 bulbs consumed nearly 2A of current at 13v. Multiplied together this is the wattage of power consumed, about 30 watts. (I like to round stuff!) bear in mind a great deal of that power is lost as heat- In fact only about 2% of the input energy comes out as light!  LEDs are also inefficient, only less so.
I did some experiments with bayonet style direct plug in replacement bulbs. These produce light in all directions so that some sort of reflector is required, and none were particularly bright.
I also found the usual colour of ‘white’ LEDs tends to be a lurid broad daylight hue that did not feel warm or cozy at all. I found it’s possible to buy LEDs by ‘colour temperature’ where that bluish light is roughly equivalent to how an object would glow if heated to 6000 Kelvin- basically, garish arc-light colour. Great for detail work and garages… not for a cozy camper.
4000K is  a ‘cooler’ colour and was much more pleasant as this is closer to the colour  temperature of a tungsten filament.

LED Panel
The yellow color of the individual LEDs here  is in fact a phosphor material that glows under the influence of the BLUISH light that it’s easier for the technology to produce.

I also found one can buy inexpensive ‘ganged’ LED 2′ square panels from China containing 48 LEDs and their required current limiters (more about this later) for $2 apiece with a pair of wires that will connect directly to 12v

Here we are! the bare white tinplate behind the lightbulb

here we go: Taking the light fixture apart, I cropped off the tin-plate bulb-holder leaving a bare tin white painted back plate: let’s stick the LED panel to that.fffff

Double Sided Tape included, but it’s not heat-proof
Re soldering
Fo Resoldering the wiring