Mod Edit: a new thread has been made for 2022 knowledge - thanks to Eddy for the info below with some of it re-used
The question has come up many times in the past, what is better to use for RGB strings, 5VDC or 12VDC. Well this will depend on what the individual needs are, so below i have tried to explain the differences so people can make up their own decisions based on the information provided. Im sure there will be others that will add to this thread to help people make an informed decision.
The differences between using 12vdc and 5vdc pixel strings both have advantages and disadvantages
* 12VDC allows longer strings due to less % of voltage drop over the same distance as 5vdc
* 12VDC will use and waste a lot more power than 5vdc which means providing more power supplies
* Some 12vdc strings like the 180x series run in constant voltage mode as apposed to constant current mode. LEDs are a current devices so constant current is a better method of control. Im not sure if the 12VDC 2801 pixel string has been set to run in constant current or constant voltage mode.
* 12VDC will dissapate a lot more heat than 5vdc due to the wasted energy.
* 12VDC will let out less effective light output compared to 5VDC due to running at lower currents
* 5VDC requires more power injection due to both the higher currents and higher % of voltage loss over the same distance as 12VDC
* 5VDC requires larger guage wire compared to 12VDC for the same power requirements.
* 5VDC is much more efficient than 12VDC and requires less power supplies for the same amount of light output.
To see this we will compare a 12VDC and 5VDC string using the common 8mm LED
8mm RGB LED Specifications
Red - 20millamps - 2 volts
Green - 20 milliamps - 3.2 volts
Blue - 20 milliamps - 3.1 volts
So to run the red LED we need to drop the voltage from 12VDC to 2VDC, as you can see there is a much higher % of volts that need to be lost to run at 12VDC compared to that of 5VDC. So there is a lot of wasted energy. One way that is used to to minimise the amount of lost energy through a 12VDC string is to run the LEDs at a lower current, so instead of running the LED at the rated 20ma for each colour, they will instead be set to run at 10ma (these values may differ), this then reduces the amount of wasted energy due to the lower current needs of the LEDs. But as LEDs are current devices, the lower current will reduce the light output. Now normally at 10ma the human eye cant really notice a great difference when looking at the LED compared to being run at 20ma, but what happens is the effective light output is reduced and this will show with a light meter, this will then reduce light wash and surrounding light generated by the LED.
The reason why we see 12VDC strip and modules is because they have 3 LEDs connected in series, so the red LED circuit would then be 6vdc (3x2v), this makes much better use of 12VDC than using a single LED.
5VDC is used for single LEDs and 12VDC is used for multiple (3) leds. 12VDC string were designed to help overcome the voltage drop and current needs of using 5VDC strings.
So now knowing the differences and the advanatges and disadvantages should help people decide if they prefer to use 5vdc or 12vdc strings. Personally i use a lot of strip and modules because it is 12VDC and makes efficient use of the power used compared to running 12vdc strings. The little strings I do have are 5VDC because that is the correct and most efficient design for using single LEDs
So really it goes down to
12VDC = Longer string length, more power used, low efficiency
5VDC = Shorter string length, less power used, high efficiency
12VDC Strings or 5VDC Strings, what is best to use - 2022 update
This is a 2022 update of fasteddy's original 2012 post https://auschristmaslighting.com/threads/12vdc-strings-or-5vdc-strings-what-is-best-to-use.2595/ Updated to reflect 2022 knowledge. 12v or 5v? The question has come up many times in the past, what is better to use for RGB strings, 5VDC or...
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The question has come up many times in the past, what is better to use for RGB strings, 5VDC or 12VDC. Well this will depend on what the individual needs are, so below i have tried to explain the differences so people can make up their own decisions based on the information provided. Im sure there will be others that will add to this thread to help people make an informed decision.
The differences between using 12vdc and 5vdc pixel strings both have advantages and disadvantages
* 12VDC allows longer strings due to less % of voltage drop over the same distance as 5vdc
* 12VDC will use and waste a lot more power than 5vdc which means providing more power supplies
* Some 12vdc strings like the 180x series run in constant voltage mode as apposed to constant current mode. LEDs are a current devices so constant current is a better method of control. Im not sure if the 12VDC 2801 pixel string has been set to run in constant current or constant voltage mode.
* 12VDC will dissapate a lot more heat than 5vdc due to the wasted energy.
* 12VDC will let out less effective light output compared to 5VDC due to running at lower currents
* 5VDC requires more power injection due to both the higher currents and higher % of voltage loss over the same distance as 12VDC
* 5VDC requires larger guage wire compared to 12VDC for the same power requirements.
* 5VDC is much more efficient than 12VDC and requires less power supplies for the same amount of light output.
To see this we will compare a 12VDC and 5VDC string using the common 8mm LED
8mm RGB LED Specifications
Red - 20millamps - 2 volts
Green - 20 milliamps - 3.2 volts
Blue - 20 milliamps - 3.1 volts
So to run the red LED we need to drop the voltage from 12VDC to 2VDC, as you can see there is a much higher % of volts that need to be lost to run at 12VDC compared to that of 5VDC. So there is a lot of wasted energy. One way that is used to to minimise the amount of lost energy through a 12VDC string is to run the LEDs at a lower current, so instead of running the LED at the rated 20ma for each colour, they will instead be set to run at 10ma (these values may differ), this then reduces the amount of wasted energy due to the lower current needs of the LEDs. But as LEDs are current devices, the lower current will reduce the light output. Now normally at 10ma the human eye cant really notice a great difference when looking at the LED compared to being run at 20ma, but what happens is the effective light output is reduced and this will show with a light meter, this will then reduce light wash and surrounding light generated by the LED.
The reason why we see 12VDC strip and modules is because they have 3 LEDs connected in series, so the red LED circuit would then be 6vdc (3x2v), this makes much better use of 12VDC than using a single LED.
5VDC is used for single LEDs and 12VDC is used for multiple (3) leds. 12VDC string were designed to help overcome the voltage drop and current needs of using 5VDC strings.
So now knowing the differences and the advanatges and disadvantages should help people decide if they prefer to use 5vdc or 12vdc strings. Personally i use a lot of strip and modules because it is 12VDC and makes efficient use of the power used compared to running 12vdc strings. The little strings I do have are 5VDC because that is the correct and most efficient design for using single LEDs
So really it goes down to
12VDC = Longer string length, more power used, low efficiency
5VDC = Shorter string length, less power used, high efficiency
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