Read carefully or you could be very wrong!
Constant Voltage (CV) systems are good thing
.... but the important thing here is the "decentralized" current regulator, which is often replaced with passive components (resistors) which are not actively regulating the current, they reduce the current drawn by LEDs in their series, but lowering the Voltage will lead to decreasing the current, and what is worst, increasing the voltage will lead to overcurrent/overheating the LEDs, causing very quick deadth...with resistors, there is simply no active current regulation with almost no protection at all.
Example of such "basic" LED strip
Schematic of such LED strip.
Lets have a look on few graphs showing Brightness vs Voltage dependency for Constant Voltage system LED strips :
Diagrams on the graph shows bellow comparing 12V LED strips (left 2 shapes) and 24VDC LED strips (right 3 shapes) explains :
- both STANDARD LED strips contain only resistors, thus their brightness (Y-axis)is increasing almost in linear with increasing Voltage (X-axis), until the LEDs are overheated due to overpower, then their brightness falls starts to decrease and the LEDs die. Low power LEDs (12V Standard LED strip on left) are not able to heat up the LED strip that much, but running them above their "maximum allowed current" leads to failure anyway.
- MASTER LED strips contain CC IC (Constant current IC / driver) which is basically doing nothing until the Voltage "Umin" is reached where the current will reach a value set on the driver. At this point the brightness is 100% and any other Voltage increase will not impact the brightness of LEDs, as the CC IC driver will actively keep the current to the value where it is set. Thanks to this active current regulation, it is possible to power up the MASTER LED strips not only with Utyp (Typical Power supply say 24VDC) but with Utyp2 ....all the way upto Umax...explained more in depth bellow .
MASTER LED strips are working always OK even at these areas (no overheating, no overcurrent, no overpower, no lifetime and light decay, etc)
Graph "Allowed Voltage drop limits" shows the range of allowed Voltage where the LED strips are working OK (and with even and 100% identical brightness)
Lets focus on 2 comparisons :
-
12V vs 24V LED strips
and - Allowed voltage range within each Voltage system
12V vs 24V showsfor both STANDARD LED strips (with resistors) almost identical Voltage range (red and blue continuous part of graph shapes)...As you can see , no 2 LEDs on the strip will have identical brightness, as they will never have identical current....as the voltage changes due to resistance (on wires and LED strip itself), it continuously "reduces the brightness" ... a range of 90%-110% is agreed as "allowed" for this kind of LED strips...the size of continuous shape is small (normally you must use thick wires, and short distance, to limit the Voltage drop outside of the LED strip to minimum....otherwise your LED strip will never reach power output nothing close to 100% )
In oposite these basic STANDARD LED strips (with resistor only) our MASTER LED strips with constant current drivers (CC IC) have their limits several times better, allowing them to be 100% bright (for example MASTER-LONGRUN is 100% bright when Voltage is anything between 17.5V upto even 36VDC )
When powering these LED strips from 24VDC you can easily count with Voltage drop on wires + LED strip itself upto 6.5V! (24V-17.5V=6.5V) As many power supplies have ability to "increase its output voltage " by 10-15% to cover the Voltage drops on wires, you can be sure that they will be never overheated and their lifetime will be identical as if powered from 24V or 21V ...does not matter.
