LED strip soldering/extending

I bought two L3 5M long LED strips. Two because I need 6m and the plan was to take a missing 1m and solder it to the other. Unfortunately after soldering the new section won’t light up. I’ve measured it with multi meter and current is flowing.
Unfortunately there are no stripes longer than 6M available to buy. Am I doing something wrong or L3 can’t be extended?

Is the polarity of the extension correct?

it is, are they allowed for extending at all? User manual is very poor. I am asking because maybe I am trying to achieve something that is not possible with these stripes?

There are no technical obstacles provided that the driver is capable enough. If you cut at the marked point and make the connection correctly, it must work.

Is it an official statement or have you tried it? I found in the manual that once you cut it for example it can’t be soldered again and it doesn’t mention anywhere in L3 manual that you can extend it. What I found instead but for L1 not L3 is that you can extend it by plugging extra power supply in between.

This is a logical assumption. I have practiced cutting and soldering many times on other LED strips. I do not understand why it cannot be restored if you cut it. It is, after all, a simple galvanic connection. Nothing fancy.
This extra power supply in between is to ensure adequate current capacity. As I think they call it an “amplifier” because this extra power supply is controlled by the current given by the main power supply, to put it simply. Because if you extend the strip and the power supply can’t deliver enough current, the LEDs will pulsate or not light up at all. You can also overload and the power supply can fail, although generally switching power supplies are overload proof.
Do both sections fail to light up after soldering or just the added one?

It is logical for me as well thats why I bought two of them to extend it. The only thing comes to my mind is that the controller measure resistance and then cut the soldered part. Yes, the not working part is the one I soldered in. I’ve tried twice in to different places checking current after soldering point.

For longer strips, the solution is to supply power at both ends of the strip (if the power supply is powerfull enough).

But how will I know this? For now it looks like it is not properly soldered because even if I cut the working part and solder it back it won’t shine which is described in the manual that once you cut it you can’t solder it back. For me it looks like the WiFi controller has a logic to check resistance?

I doubt that. How about powering up the added part directly? Did you try this?

I haven’t and it is too late for it now because I put it in the bin and changed the whole concept. I will try maybe in a month time when I’ll be installing new led stripe along the second stairs.

Good luck then :sunglasses:


I personally bought many of them, one of them was not working well at the end of the strip. I cut the wrong part and replaced it by a remaining part of another one which were too long. I sold it and t work perfectly. However, in the settings, you need to add the quantity of led that you have, by default it’s 150, I’m sure that you can add more.L3-5M-P is the model a referred to.

Hey @kevin.amandacoombes @horizn

Both L3 and L3 Pro DO NOT support extensions.

Man is a lifelong learner.

@ward In what sense are they not supportive? Will cutting and then joining the same sections make the whole not work? Or will adding a new section make it so? Is it about the performance of the power supply or is there some higher intelligence in the strip? Is it known or not known?