Basics of Strip Lighting Constant Voltage Strips Vs Constant Current Strips

The most important question that confuses a lot of people, (including some electricians) is how far a strip can run before it needs to be powered again. Here, we are not talking about the distance of the wire run between the driver and the strip. We are discussing the actual length of the strip light. 

In order to explain the answer, we need to understand the two types of strips

1. Constant Current Strip lights have a current balancing ICU on each cutable unit of the strip. This current balancing ability of this strip light enables it to run for longer distances without needing to be re-powered. Even in this type of strip, the distance it can run for will depend on how much power it can handle per linear metre. In simple terms, if all other specs are the same, a constant current strip with 10W per linear metre would run for 20 metres lenght, whereas an 18W strip may only run for 10 metres without needing power. In summary, in order to achieve more run, you are going to have to sacrifice the power (light output). Unfortunatley, we can't have it all. 

While we are on this subject, please note that a Constant current strip will still need to be powered by a Constant Voltage power supply. Constant current power supplies (drivers) are reserved for lumiaires that are designed specifically to work with those driver. Examples are flood lights, downlights, high bay lights , panel lights etc. 

Pros of Constant Current Strip Lights

a. Can run longer, provided you are not after a very powerful strip. 

b. Constant Voltage strips can be daisy chained, as long as you don't exceed the total recommended lenght of the strip. To eloborate further, say your Constant current strip is specified to run for 20 metres without needing to be re-powered. You can run wires to an 8 metres piece of a constant current strip, then connect to non powered end of this 8 metre strip another 10 metre strip and theoretically it should not cause any luminance drop in the second 10 metre strip. 

Cons of Constant Current Strip Lights

a. LED Density per metre is usually much lower than Constant Voltage strips. 

b. Not designed for areas where you need the strip light to make a lot of lumens. 

c. Constant Current strips usually are more pricey because they have to have a current balancing ICU .

d. Usually the PCB is relatively wider because the ICU is generally integrated to the side of the chip. This disadvantage has recently been looked after as the trend has started shifting towards the current balancing ICU being integrated into the LED chip. 

2. Constant Voltage Strip Lights

Constant Voltage strip lights are generally recommended to run for 5 metres. You can choose to run them up to 6 metres if you power them from both ends. Constant Voltage strips will usually start showing a luminance drop on the non powered end if you try to run them for longer than 5 metres. Despite this disadvantage, Constant Voltage strips are the more commonly used strips. Below are the pros and cons of Constant Voltage strips

Pros of Constant Voltage strips

a. Constant Voltage strips will have a lot higher LED density compared to Constant current strips.

b. Constant Voltage strips can be made to handle more power and thus more suited to high lumen outputs. 

c. The PCB can be a less wide as it doesn't require room on the PCB for a current balancing device. 

d. Usually not as pricey as their constant current counterparts 

Cons of Constant Voltage Strips

a. They need to be powered every 5 metres. 

Please note, that you can use the save driver to power the second run of the strip, as long as you run the tail wires back to the driver. You cannot run constant voltage strips in daisy chain forms. Every time the tail wires have to go back to the driver directly. 

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