Custom LED lights without burning down the house
February 9, 2011 4:55 PM   Subscribe

I've been looking around at lighting options for my bedroom, and my geeky self decided that custom LED strip lighting would be awesome. Then I read previous AskMe's and want to make sure I can do this without burning down my house! Questions and a search for the easy way inside!

This all started with a wander through IKEA, and they have their Dioder LED light strips and all sorts of suggestions on how to install this behind your TV, in your cabinets, along the ceilings, etc. I figured there had to be a cheaper (per amount of lights and lumens) way to get bunches of LED's around my bedroom. I spotted this reel of LED light strips and thought to myself, omg, I can cut this down, use some sort of wiring and boom, have a full custom LED job probably for under $100. I saw another website that had a bunch of accessories, including 12VDC adapters, splitters, connectors etc. that make it seem like I could wire this whole thing up easily and do it safely.

I'm probably looking at cutting the 5m warm white reel into roughly 4 or 5 strips, using a 36W 12VDC adapter, 5-way splitter, connecting via 5x Flexible LED Strip Light DC Plug Connector.

I then read through the AskMe's (above) and saw a lot of talk about needing resistors to prevent the whole mess from overheating, killing the LEDs, letting out the smoke.

That all being said, my questions: It appears that these LED light strips have resistors built in to make the strips both series (three per series) and parallel (x number of groups). Will I still need to wire in or solder in a resistor to prevent the whole thing from releasing the smoke or catching fire? Is there a certain size of adapter I should be using to power roughly 16 feet of LED lighting and not have to drop in more resistors? Are the resistors already built in to the DC adapters? Is there any danger of using these DC 2/3/5-way splitters?

Am I greatly overthinking all of this? I feel like I am.

I'm not particularly afraid of electronics, but I know there are MeFites who are way more knowledgeable than myself. If anyone has used these light strips, tell me all you know! Thanks AskMe!
posted by Mister Fabulous to Science & Nature (4 answers total) 8 users marked this as a favorite
 
I have used products like the light strips you link to. You do not need any resistors or power regulators; you just need a reasonable approximation of 12VDC.

It appears that these LED light strips have resistors built in to make the strips both series (three per series) and parallel (x number of groups).

Yes. Exactly.

Will I still need to wire in or solder in a resistor to prevent the whole thing from releasing the smoke or catching fire?

No. It would be difficult to convince this system to catch fire, even if you wanted it to; the power adapter would overheat and shut down first.

Is there a certain size of adapter I should be using to power roughly 16 feet of LED lighting and not have to drop in more resistors?

If you try to power too many LEDs, they will draw more power than the power adapter is capable of supplying, and it will overheat. This may or may not permanently destroy it.

The splitter is designed to let you power multiple devices in parallel. That is, each device gets the same voltage, and the splitter draws as much current from its source as the sum of each device. This is exactly the same way the strips are already set up to run. Electrically speaking, cutting the strip in pieces and connecting them using that splitter is exactly the same as running a single strip.

Am I greatly overthinking all of this? I feel like I am.

Yep. It will work fine. The 36 watt power supply you have selected is adequate for the 24-watt rated power consumption of this strip, and splitting the strip into pieces will not change that power consumption at all.
posted by Mars Saxman at 5:10 PM on February 9, 2011 [2 favorites]


Your plan is sound. You need to cut the strips where it says to (that page says in increments of 3 LEDs). There are current-limiting resistors in every group of 3 LEDs, you don't need to add any yourself. (This is true no matter how many groups of 3 you put in your string; it just means that as long as you cut on the cut lines, you don' t need to monkey w/ resistors.)

You should make sure all your sub-components (eg the splitter) are rated to handle the current load; that reel says it's 24W to drive the whole reel, so 2A @ 12V. Don't bury the wires in a wall and you'll be fine.
posted by range at 5:10 PM on February 9, 2011


You both rock, thank you!
posted by Mister Fabulous at 9:35 PM on February 9, 2011


I reckon these, over at Dude Craft, look cool.
posted by honey-barbara at 2:45 AM on February 10, 2011


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