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2006 Ram 1500 4.7L w/ 6 speed standard. Little to no accessories. Strictly a 'trade' model. No power windows; no power door locks; no power nothing. Alternaternater rated at ~135 amp.

If I disconnect the top rear cab incandescent reverse light and use the power source for multiple LEDs, how much can I over-tap the stock supplied power before I need a relayed power switch?

I backup a lot (towing and lining up a tow) at all times of the day and night and need to know where I'm going.

Before anyone starts questioning my choice of towing vehicles, I have a few of them and the others are various forms of diesel transportation.

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    What wattage lamp is currently fitted? You probably want to keep the total current drawn by the LEDs the same as the existing lamp so that you don't risk overloading the reverse switch.
    – HandyHowie
    Commented Feb 5, 2020 at 9:34
  • The 'rear cab ... reverse light' is also known as a 'cargo light'. A Sylvania 912ST or 912LL seems to be a standard bulb.
    – user16128
    Commented Feb 5, 2020 at 9:44
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    @Jeeped the 912ll is 12,8w so if the led consumption is below 15watts you will probably be in the safe range,i am not sure about this so i made it a comment.
    – trond hansen
    Commented Feb 5, 2020 at 11:54
  • @trondhansen - Thanks for your input. I'm just researching new gen LEDs. The last time I swapped out incandescent for LED was replacing '97 TJ taillights and those needed a ballast resistor. I'm just feeling out other peoples' experiences. Thanks again!
    – user16128
    Commented Feb 5, 2020 at 12:49

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Incandescent bulbs produce somewhere around 11 lumens of light per watt on average, so a 12.8W would produce about 140 lumens of light. LEDs produce about 80 lumens per watt on average, so you'd get over 1000 lumens off of a 12.8 watt LED.

So the short answer is you'll get 8 times more light from an LED. 1000 lumens is close to a high beam headlight, which may be brighter than you want. I'd actually tone it down to a low headlight level so you don't blind drivers, 700 lumens is about 9 watts.

The long answer is you may not just be able to swap bulbs because the bulb will be bigger - it takes a lot of LEDs to produce that much light, you might not be able to find one with the same kind of plug either. You'll most likely need to fit some sort of fixture for it.

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