DIY: Rear hatch LED light strip

[IQ_imbalance]

Here is what different gauge wire can handle. If you want to be super conservative, never exceed 80% of this. And make sure your fuses are less than this; the goal is for the fuse to blow before the wire melts and starts a fire.


14 -- 11.8 amps (162 watts)
16 -- 7.4 amps (102 watts)
18 -- 4.6 amps (63 watts)

Thanks. Looks like the strips i'm looking at are 60 LED/m and (max) 0.4W/LED...so 24W/m, and that's 2A at 12V for the 1m strip of LEDs. Eyeballing it looks like maybe 6 feet between switch and LED strip, so that's a 12 foot wire run total. 18 awg should be plenty for the single strip based on various online 12V wire size calculators.

Here's where it gets fuzzy for me:

If i add another 1m strip (like @Redbaron73 did), and run both circuits through the same SPDT switch, wouldn't that be treated as a parallel circuit so the above calculations would apply for the additional LED strip (as long as the SPDT switch can take the additional amps?) Or do I have to size all the wires for a 48W circuit (call it 5A) and the new total wiring path (let's say an extra 6ft there and back)?

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[bobholthaus]

Thanks. Looks like the strips i'm looking at are 60 LED/m and (max) 0.4W/LED...so 24W/m, and that's 2A at 12V for the 1m strip of LEDs. Eyeballing it looks like maybe 6 feet between switch and LED strip, so that's a 12 foot wire run total. 18 awg should be plenty for the single strip based on various online 12V wire size calculators.

Here's where it gets fuzzy for me:

If i add another 1m strip (like @Redbaron73 did), and run both circuits through the same SPDT switch, wouldn't that be treated as a parallel circuit so the above calculations would apply for the additional LED strip (as long as the SPDT switch can take the additional amps?) Or do I have to size all the wires for a 48W circuit (call it 5A) and the new total wiring path (let's say an extra 6ft there and back)?

I don’t know exact length’s before you have to calculate voltage drop over distance, but I know for certain 6’ isn’t enough to worry about.

If you’re using a single wire to run 2 strips, yes, you sum the watts. If you’re 4A at two of your strips, 18g at 6’ is probably perfectly fine. The 80% rule on such a light load isn’t much to worry about. But if you have 16 gauge lying around, you might as well upsize and sleep soundly at night.

In summary: I think you could run 16g to the switch, and then 18g to each strip. I think the switch acts as a splitter, but I’m not certain. But at 4 amps, you still have .6 amp margin (15%), so you’re probably fine with 18 all the way through. But 16 is cheap… so why not?

ps. 4.5 amp fuse, max!

 

[LWLjeep]

Night time ops are easy now

Looks really nice, thanks for the info. This is something I've been looking into.

 

[IQ_imbalance]

Slowly coming together. Huge mismatch between the <20GA wires that they give you on the LED strip header vs. the 12GA wires I'm running for power, so going to have to make sure i've got some serious strain relief built in.

 

[bobholthaus]

Slowly coming together. Huge mismatch between the <20GA wires that they give you on the LED strip header vs. the 12GA wires I'm running for power, so going to have to make sure i've got some serious strain relief built in.

Why 12ga? Isn’t that hugely oversized? That can handle 18.6 amps or 256 watts (or 80% of that if you really want to be conservative), and it’s a challenge to run and crimp, etc. It's always good to oversize, but in my opinion (which you didn’t ask for), you’re creating a lot of work for yourself and it will be harder to work with and hide.

18 gauge handles 4.6 amps/63 watts; it’s what I used for my Rigid 360 SAE fog lights and it’s plenty. I can’t imagine the draw on these strips is more than 5-10 watts?

Btw, all of you guys may consider checking out MOLEX Perma-Seal connectors HERE. They make step down connectors as well, which have enough heat shrink and sealant to connect an 18-22 to a 10-12 wire. They aren’t cheap, but they are bombproof. Get their crimper too; every connection in my JK used these, and now my JL. The wiring will be together long after these vehicles have left the road!! I can’t sing their praises enough. Waytek Wire is a place you can order them from.

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