Advice on wiring up LED strips - Page 1
Forum section: electronics / projects

author: Hash Brake
author_rank: Newbie
timestamp: February 02, 2021, 03:48:20 pm
content: Hello!First of all, this is my first post so my apologies if I miss anything or do not follow customsI am trying to wire up a small RGB LED system in my bedroom and would care for some advice on the best/safest/most efficient way to wire up the LED strips. I have four rolls of 5m long LED strips (see specs below) and I would like to lay them out as seen in the diagram attached (see 'Wire attachments diagram' attached): 2x for the bed, 1x for the wardrobe, 1x for the shelves (which will be cut in pieces of 1m, 2m and 2m).Specs of LED strip:I'm buying from Shopee (an asian Amazon) and this is all the info I could pull from their page- 5050 LED RGB- 60 LEDs/m- 12W/m (0.2W/LED)- Uses 12V- IP33 protection (basically none)- Uses a 4 pin connection (Ground, R, G, B)Link:https://shopee.vn/CUỘN-LED-DÂY-RGB-7-MÀU-5050-5M-i.128934242.2473269273(1) After a bit of research, my initial though is to wire the three shelf strips in series and everything else in parallel with each other. The reasoning behind this is that these are very cheap LED strips so I'm guessing that voltage drop will be significant for any length over 5m.(2) In total, I will be running 20m of LED at 12W/m so 20x12 = 240W. This means that I need a PSU that is capable of delivering 300W (taking into account the 20% safety margin that is recommended). Using P/V = I, 300W/12V = 25A. So I will be needing a PSU rated at 12V and 25A???(3) Also, how could I incorporate an LED controller unit rated att 12V 6A(see picture attached) without breaking it if that much current is needed? Link:https://shopee.vn/44Key-IR-Remote-Controller-for-RGB-5050-LED-Light-Strips-i.116330449.2668806074Alternatively, I've found another unit that does the same job which is rated at 12-24V and <192W?? (see picture attached below) Will that help? Link:https://shopee.vn/【chendujia】Mini-Bluetooth-Wifi-LED-Controller-Remote-For-5050-3528-RGB-RGBW-LE-i.253123873.6445331672(4) Lastly, I would also line my ceiling using 20m of the same kind of LED strip (in a rectangular shape), how would I achieve that. (This would use a separate PSU and LED controller unit) and using what PSU?Questions summary:(1) Is my proposed method of wiring the strips correct?(2) What PSU should I use for this system?(3) How can I incorporate an LED controller unit without frying it?(4) As a separate system, how can I line my ceiling using the same kind of LED (20m rectangular shape) and what PSU should I use?Any help, comment or suggestions are welcome! Even if it's to tell me that I will burn my house down completelyThanks,H

author: tunk
author_rank: Super Contributor
timestamp: February 02, 2021, 05:33:53 pm
content: The wattage rating probably is exaggerated, so I would firstfind out how much e.g. 5m uses, and then get a suitable PSU.Then again, the rating of some PSUs may be exaggerated ....

author: ledtester
author_rank: Super Contributor
timestamp: February 02, 2021, 05:58:23 pm
content: For "dumb" led strips there are these devices called "led amplifiers", e.g.:https://youtu.be/dmwVUa6YC-kSo you can have one controller but multiple (and thus smaller) power supplies along the length of the strip.

author: coromonadalix
author_rank: Super Contributor
timestamp: February 02, 2021, 05:58:30 pm
content: For 16ft led strips rgb or only whiteI put then in an y fashion Ie : one distribution supply wire for 2 led strips in parallel, never in serial, the base flexible board for the leds could overheat and your led strip life could drop significally.A 16 feet led strip could easily consume 2-3 amps of current, a dual row led strip can go p to 4-6 amp, the rgb (white) color is the one who consume the highest current, for a single white color led strip, it can be lower.You use an rgb (wifi or infrared) controller for white and rgb led strips and use buffers boxes, they will use the rgb / white signals and distribute them, where you need, but they need the same power supply each.In the end you may need a beefy psu depending how much strips you need

author: tooki
author_rank: Super Contributor
timestamp: February 02, 2021, 06:04:33 pm
content: Quote from: Hash Brake on February 02, 2021, 03:48:20 pmMore like “significant for any length over 1m”. The thin copper traces of the LED tape is just so darned thin that the voltage drop is a big problem. :/ Read on:Quote from: tunk on February 02, 2021, 05:33:53 pmIn my experience, the rated wattages are actually correct — if by that you mean calculating the power of one trio of LEDs and multiplying that out to the length of the strip. The reason you never get it is that the voltage drop along LED strips ishorrible. If you take a 5m strip and just power it from one end, you’ll be lucky to get more than half the rated wattage. Feeding it from both ends, maybe 2/3. To get it all, you really need to run fat wires alongside it, supplying power at every single set of power pads.

author: Hash Brake
author_rank: Newbie
timestamp: February 02, 2021, 07:59:18 pm
content: Quote from: tunk on February 02, 2021, 05:33:53 pmThis is definitely a sensible idea although it'll take nearly a month for everything to get shipped over so until then, I can only stick with the rating they give meQuote from: tooki on February 02, 2021, 06:04:33 pmI agree although I've had one of these strips in the past and I find the voltage drop over 5m to be negligible (for me at least). Which is why I didn't have any strips daisy chained longer than 5m in my initial diagram.Quote from: ledtester on February 02, 2021, 05:58:23 pmThis is a viable solution for the 20m ceiling system! Although for my bed/shelves/wardrobe system, it would be nicer to have everything run off from only one PSU.Quote from: coromonadalix on February 02, 2021, 05:58:30 pmCould you kindly elaborate on what a 'buffer box' is?Also, say that I connect two strips in a Y fashion as you described, do the two branches have to have the same power consumption (ie. draw the same amount of current) or can it be different (ie. one branch is 5m so draws 5A (60W/12V) and the other is 10m so draws 10A (120W/12V))?

author: RJSV
author_rank: Super Contributor
timestamp: February 08, 2021, 04:17:17 am
content: I don't know how to criticize nicely, but here goes:Uh, do you want to learn electronics, ... or are you practicing to be a factory worker, assembling whatever, needing exact literal instructionsAnyway, that was my initial thought, but you have a nice question. Myself, I would avoid piling everything together, when you could make, say, three separate systems; plus that makes for flexibility for making a change, here and there. So, maybe that would cause a clutter, of hand controllers.I've tended to buy quite a few different LED strip controllers, at the local auto parts store, (although they generally don't supply a huge data sheet.Any chance you could try a couple strips first, you might discover some small 'alternates' layouts, as you go.A big concern I always have, is finding out what size load resistor(s) being used. A white LED flashlight for example, would use a resistor around 330 ohms. But that's the first thing to pay attention to, along with any internal strip wiring (is that in your manufacture data sheet ?

author: RJSV
author_rank: Super Contributor
timestamp: February 08, 2021, 05:08:39 am
content: In specific answer, to your question on the 'Y' connection of two strips in parallel, the two are each simply a 12 volt device, so yes, you can just hook them up. Those numbers sound a bit high, for a bedroom filled w bright light.Uhh, instead of hooking everything, like two strips at 5 amps apiece, looking for a 10 amp capacity psu, why not have two separate systems, each could then use those 7 amp PSU s you are thinking of using?But, again, as long as your two strips are '12 volt powered', or any 12 volt device, like a fan, don't really interact, unless they share a 'load limiting' resistor. That isn't a complete answer, as I don't know if that type of LED strip has it's own integral load limiting resistor, and I don't know if the strips themselves do some partially in series, or if all are parallel (more likely).As those strips are sold without PSU, does the info spell out a typical recommended PSU type ?Otherwise, you are kind of left on your own, there, in terms of setting up for the proper current wanted.Oh, and plus you (me also) need to start considering some real power in any load limiting resistor, which can turn out to be 10 ohms, at 5 amps... That's some large power resistor, at 250 watts, if I got that right.Another issue, is that p/n strip the type and looks that you want ? I've often installed whole sets of parts, only to discover a much better item the next week.I think I would start with a few strips, separate, and probably forget 'serial' connections if you want regular brightness. After all, 12 volt strips are for using 12 volts...(sorry, I can be a jerk sometimes, not your problem )AND, can the layout be done, all with same length strips? You save some trouble there, as the whole task is separated into sub-sections.