Led strip , to much current? - Page 1
Forum section: electronics / beginners

author: GoatZero
author_rank: Regular Contributor
timestamp: November 30, 2013, 09:04:57 pm
content: I bought a 3M led strip, the package said they use 12V-24V 220mAI divided the strip in 3 and now Im getting really confused,now i have 3 led light strips with 72 leds each, using a 19V 3.92A power supply (ac adapter) and i connected in parallel the 3 strips, according to my multimetter conected in series they are wasting 3.5Ampers just from that reading, how the fuck am i supposed to use this to light up anything they waste that much current much energyA common led bulb wastes .5A and gives more light than these 3 led strips together, could anyone please attemp to explain whats going on?also the ac adapter its getting way to hot, 70C after 30 min

author: IanB
author_rank: Super Contributor
timestamp: November 30, 2013, 09:06:39 pm
content: Didn't you ask this question before? I know someone did......yes, here it is:https://www.eevblog.com/forum/projects/help-with-led-light-strip-set-up/

author: IanB
author_rank: Super Contributor
timestamp: November 30, 2013, 09:10:41 pm
content: Can you post a link to the exact LED strip you bought? Nobody can help you without knowing the technical specifications of the LED strip.

author: GoatZero
author_rank: Regular Contributor
timestamp: November 30, 2013, 10:53:45 pm
content: Quote from: IanB on November 30, 2013, 09:06:39 pmYeah i did after i havent solved it since i have been busy with schooli thougth my thread was lost so i started another since i want to fix this weekendim back on working in this problem since i havent been able to solve it, the Led light strips are rated 12-24Vdc and 220mA, i already did some calculations, turns out each leed needs 16mA to turn oni already made the series arrangement i did not turn the 3 strips but it did turn on 2 at 50% light (using 19v 3.92 ac adapter)So now i got a 24AC transformer, i just did right before writing this post rectify the signal and now its pumping 33VDC i got 3 led strips to turn on while using only .227 Ampers, why makes way more sense now however the strips are still only turning at 70% of their brightness, i wonder if i should increase the voltage even more..., im checking temps and everything its running around 22C room temp its currently 18CRight now everything seems to be working fine, however i kind of miss the brightness i had when running the strips at 4A..... which leaves me wondering, how can i increase the brightness... and im guessing... that now i need.... more current....i gues i wil just feed the other 2 strips with another power supply

author: GoatZero
author_rank: Regular Contributor
timestamp: November 30, 2013, 10:57:06 pm
content: Quote from: IanB on November 30, 2013, 09:06:39 pmthanks for the link tho, im reading it all over again

author: IanB
author_rank: Super Contributor
timestamp: November 30, 2013, 11:17:14 pm
content: Quote from: GoatZero on November 30, 2013, 10:53:45 pmIt's really going to be impossible to help you unless you can post a link to the product you have bought.Strips rated for "12-24 V DC" doesn't make sense. There is no way to have such a variation in voltage on a simple LED strip product.A typical design for one 3M LED strip I looked at was to have sets of three LEDs in series with a 150 ohm resistor. When powered with 12 V this produces an LED current of about 17 mA. The strips can be cut up in lengths of three LEDs at the marked cutting points. So for instance if you cut the strip to contain 30 LEDs then the current required would be 170 mA.These LEDs are designed for area lighting so they will not be blindingly bright. However, if you have 30 or 60 LEDs all running at once in a long strip the total light produced should be quite reasonable.

author: peter.mitchell
author_rank: Super Contributor
timestamp: December 01, 2013, 03:22:46 am
content: can we even have a close up picture of the strip?does it look exactly like this:

author: Towger
author_rank: Super Contributor
timestamp: December 01, 2013, 04:23:38 am
content: We really need the exact specs/photo of the LED strip. Most strip specs take the best figure for each parameter. In otherwords they lie. So for 5m of 5050 LEDs x 300 they quote 12v x 5a = 72w... In reality at 12v they draw around 3a.

author: holman81
author_rank: Newbie
timestamp: February 12, 2014, 04:01:10 am
content: Most 5m long 5050 LED strips with 60 LED/m ( I got mine fromhttp://www.lightingnext.com/smd-5050-fexible-led-lighting-strips-300-leds.html) are rated at 72W. This is equivalent to 72W/3 = 24W per RG&B channel.To calculate what this means in current per channel - which is what LED controllers & RGB Amplifiers are specified in - we use the formula :Amps = Watts/Volts