Should you replace default wires on LED strip
How much can a single injection point handle?
When starting out doing your own LED strip installs (Analog or Digital) there is a lot of information to digest and one of them is how much current you need and especially for 5v addressable LED strip how many injection points you need to make to have it all light up evenly and to the max of it’s potential.
To guide people in this I have my real-world LED power usage sheet which gives you much better numbers to work with then manufacturers often state and combined with that I have a power injection live stream which teaches you how to calculate everything you need from total power, how many injection points you need, power per injection point and then which size/gauge cable you need to each injection point with a given distance.
But one of the things that I assume in those guides is that an edge injection to an LED strip can effectively carry about 4Amps of current and a middle injection about double that. That’s the very reason the Dig-Quad pre-assembled comes with 5Amp fuses by default, since this suits most situations.
But why am I so sure about that? If you just connect thicker wire, doesn’t that mean it can carry more? (basically no). So I recently did a livestream to test exactly this.
The livestream video shows all tests in real-time including results and conclusions but I can understand this might be a long watch if you just want the results. For the results please see the next paragraph in this article!
The document I typed during the livestream is here but please find a condensed version of the 100% RGB white (highest power usage) tests below.
Conclusion: Should you replace the default cables?
TLl;DR No, it doesn’t matter.
Conclusion: How much can a single injection point ingest?
TL;DR Generally speaking a edge injection will handle ~4Amps and a middle injection about ~8Amps.
Conclusion: The Numbers
As you can see in the table, either using the JST connector (officially only rated for 3Amps) or connecting the extra wires or even replacing the wires with 16AWG (1.3mm2) makes very little to no difference in the amount of current a single injection point can supply to the LED strip.
Then looking at the last result you can see that adding extra current using a power injection at the end of the strip does make a very big difference and now the LED strip can draw almost double the current versus what it did using a single injection point.
This shows 2 things, a single power injection basically can’t inject more then 4Amps into an LED strip and if you want to use the LEDs on your LED strip to their fullest potential you are going to need 1 or more extra injection points transporting the extra current over separate cables.
Hopefully this article clears up some confusion regarding this setup and it allows you to better design and plan your own LED setup! Again, take a look at my “power injection livestream” which goes through all the calculations needed!
Bonus: Why is this?!
The reason a single point can’t take in more power mainly has to do with generic strip construction. Addressable LED strips consist of flexible “lanes” of copper over which power and the data signal travels. To keep costs low these only have a certain thickness, this in turn causes them to have a certain “resistance”. The more you try to push power over them the more this resistance accumulates which shows in the form of voltage drop (and heat being generated). And it’s this voltage drop which in turn limits the amount of power the strip can effectively carry from a single point.
Say we have a 5v strip, pushing 4Amps through makes this drop to say 4v which is near the bare minimum the LEDs need to function. If you’d try to push even more power through it, the voltage would drop lower then what is usable for the LEDs.
But in reality it’s “even worse”, the lower the voltage drops, the lower the draw of power will be also be in return. The LEDs are “tuned” to run at 5v and consume say 50mA of current which equates to 5v * 0,05A = 0,250w per LED. But now they’re not getting 5v but 4v, then it’s 4v * 0,05A = 0,200w per LED. And thus by pushing more current, voltage automatically drops down because of the voltage drop caused by resistance and in turn that automatically limits the amount of power an LED uses.
Hopefully that explains better why a single power injection point “can handle only so much” and the fix for this is adding extra wires (and thus more copper) to transport more power to the further points down the LED strip and inject it there.