DIY LED lamp is less powerful than expected











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I am making an LED lamp using an LED strip. The LED strip I am using is a 240 LED/m SMD2835 strip, which operates at DC12V, and is supposed to use 18W of power per meter.



My lamp is constructed as seen on the diagram: I cut it into 20cm strips, installed them on an aluminum heatsink and wired in parallel. I have tested each of the 20cm strips separately, and they draw around 0.3A of current at 12V, which is very close to the specification.



However when I wire everything together, the completed circuit draws only around 1.4A of current, which is 16.8W, while it's supposed to be around 28.8W (18W/m * 1.6m). I also noticed that each individual 20cm strip is not as bright, compared to when powered individually. I also measured voltage in the beginning and in the end of the strip - and it is much lower than 12V!



First I thought the problem is with my power supply - and I have tested it with different ones, ranging from cheap 12V 3A wall plugs, to bigger 60W bricks, but unfortunately - same result. Finally I tested it with an adjustable voltage power supply, and I noticed that when I set output voltage to around 14V, then voltage across the strip becomes around 12V and it draws around 2.5A of current, which makes it much closer to how much power it is supposed to draw according to my design (and it is much brighter, too - like when I powered 20cm strips individually).



I am very confused... Can you explain this behavior? Should I buy a power supply with a slightly higher output voltage, so that it drops down to 12V when connected to the strip? If so, how do I calculate how much output I need? Thank you.



Circuit Diagram










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  • If the voltage is measuring less than rated, then the power supply is being unable to keep up with the current demand of the LEDs (or you are experiencing huge losses in an overly long run of undersized wire). Generally speaking questions about lashups of undocumented discount consumer products don't really belong here. It's not clear that your design is sound - where in the system is current regulation supposed to be accomplished???
    – Chris Stratton
    4 hours ago

















up vote
1
down vote

favorite












I am making an LED lamp using an LED strip. The LED strip I am using is a 240 LED/m SMD2835 strip, which operates at DC12V, and is supposed to use 18W of power per meter.



My lamp is constructed as seen on the diagram: I cut it into 20cm strips, installed them on an aluminum heatsink and wired in parallel. I have tested each of the 20cm strips separately, and they draw around 0.3A of current at 12V, which is very close to the specification.



However when I wire everything together, the completed circuit draws only around 1.4A of current, which is 16.8W, while it's supposed to be around 28.8W (18W/m * 1.6m). I also noticed that each individual 20cm strip is not as bright, compared to when powered individually. I also measured voltage in the beginning and in the end of the strip - and it is much lower than 12V!



First I thought the problem is with my power supply - and I have tested it with different ones, ranging from cheap 12V 3A wall plugs, to bigger 60W bricks, but unfortunately - same result. Finally I tested it with an adjustable voltage power supply, and I noticed that when I set output voltage to around 14V, then voltage across the strip becomes around 12V and it draws around 2.5A of current, which makes it much closer to how much power it is supposed to draw according to my design (and it is much brighter, too - like when I powered 20cm strips individually).



I am very confused... Can you explain this behavior? Should I buy a power supply with a slightly higher output voltage, so that it drops down to 12V when connected to the strip? If so, how do I calculate how much output I need? Thank you.



Circuit Diagram










share|improve this question







New contributor




user655136 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.




















  • If the voltage is measuring less than rated, then the power supply is being unable to keep up with the current demand of the LEDs (or you are experiencing huge losses in an overly long run of undersized wire). Generally speaking questions about lashups of undocumented discount consumer products don't really belong here. It's not clear that your design is sound - where in the system is current regulation supposed to be accomplished???
    – Chris Stratton
    4 hours ago















up vote
1
down vote

favorite









up vote
1
down vote

favorite











I am making an LED lamp using an LED strip. The LED strip I am using is a 240 LED/m SMD2835 strip, which operates at DC12V, and is supposed to use 18W of power per meter.



My lamp is constructed as seen on the diagram: I cut it into 20cm strips, installed them on an aluminum heatsink and wired in parallel. I have tested each of the 20cm strips separately, and they draw around 0.3A of current at 12V, which is very close to the specification.



However when I wire everything together, the completed circuit draws only around 1.4A of current, which is 16.8W, while it's supposed to be around 28.8W (18W/m * 1.6m). I also noticed that each individual 20cm strip is not as bright, compared to when powered individually. I also measured voltage in the beginning and in the end of the strip - and it is much lower than 12V!



First I thought the problem is with my power supply - and I have tested it with different ones, ranging from cheap 12V 3A wall plugs, to bigger 60W bricks, but unfortunately - same result. Finally I tested it with an adjustable voltage power supply, and I noticed that when I set output voltage to around 14V, then voltage across the strip becomes around 12V and it draws around 2.5A of current, which makes it much closer to how much power it is supposed to draw according to my design (and it is much brighter, too - like when I powered 20cm strips individually).



I am very confused... Can you explain this behavior? Should I buy a power supply with a slightly higher output voltage, so that it drops down to 12V when connected to the strip? If so, how do I calculate how much output I need? Thank you.



Circuit Diagram










share|improve this question







New contributor




user655136 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











I am making an LED lamp using an LED strip. The LED strip I am using is a 240 LED/m SMD2835 strip, which operates at DC12V, and is supposed to use 18W of power per meter.



My lamp is constructed as seen on the diagram: I cut it into 20cm strips, installed them on an aluminum heatsink and wired in parallel. I have tested each of the 20cm strips separately, and they draw around 0.3A of current at 12V, which is very close to the specification.



However when I wire everything together, the completed circuit draws only around 1.4A of current, which is 16.8W, while it's supposed to be around 28.8W (18W/m * 1.6m). I also noticed that each individual 20cm strip is not as bright, compared to when powered individually. I also measured voltage in the beginning and in the end of the strip - and it is much lower than 12V!



First I thought the problem is with my power supply - and I have tested it with different ones, ranging from cheap 12V 3A wall plugs, to bigger 60W bricks, but unfortunately - same result. Finally I tested it with an adjustable voltage power supply, and I noticed that when I set output voltage to around 14V, then voltage across the strip becomes around 12V and it draws around 2.5A of current, which makes it much closer to how much power it is supposed to draw according to my design (and it is much brighter, too - like when I powered 20cm strips individually).



I am very confused... Can you explain this behavior? Should I buy a power supply with a slightly higher output voltage, so that it drops down to 12V when connected to the strip? If so, how do I calculate how much output I need? Thank you.



Circuit Diagram







led led-strip led-driver






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user655136 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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asked 4 hours ago









user655136

61




61




New contributor




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user655136 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






user655136 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.












  • If the voltage is measuring less than rated, then the power supply is being unable to keep up with the current demand of the LEDs (or you are experiencing huge losses in an overly long run of undersized wire). Generally speaking questions about lashups of undocumented discount consumer products don't really belong here. It's not clear that your design is sound - where in the system is current regulation supposed to be accomplished???
    – Chris Stratton
    4 hours ago




















  • If the voltage is measuring less than rated, then the power supply is being unable to keep up with the current demand of the LEDs (or you are experiencing huge losses in an overly long run of undersized wire). Generally speaking questions about lashups of undocumented discount consumer products don't really belong here. It's not clear that your design is sound - where in the system is current regulation supposed to be accomplished???
    – Chris Stratton
    4 hours ago


















If the voltage is measuring less than rated, then the power supply is being unable to keep up with the current demand of the LEDs (or you are experiencing huge losses in an overly long run of undersized wire). Generally speaking questions about lashups of undocumented discount consumer products don't really belong here. It's not clear that your design is sound - where in the system is current regulation supposed to be accomplished???
– Chris Stratton
4 hours ago






If the voltage is measuring less than rated, then the power supply is being unable to keep up with the current demand of the LEDs (or you are experiencing huge losses in an overly long run of undersized wire). Generally speaking questions about lashups of undocumented discount consumer products don't really belong here. It's not clear that your design is sound - where in the system is current regulation supposed to be accomplished???
– Chris Stratton
4 hours ago












4 Answers
4






active

oldest

votes

















up vote
1
down vote













From your mention of a test with a 14 volt supply, it appears that most voltage is being lost in the wires between the supply and light panel - if so, you need significantly larger wire for that connection.



All wires have some resistance, and you must consider this resistance when determining the required wire size for a given current and cable length.






share|improve this answer





















  • This. Also, these strips are actually fully powered at 14V not 12V, so even if wire resistance isn't an issue, they will not be as close to the rated current draw when only powered by 12V.
    – Passerby
    3 hours ago


















up vote
1
down vote













Most 12V LEDstrips are intended for automotive use are rated at 14.2V with engine running.



They will be dim at 9V and full brightness at 14.2 with 3 LEDs in series 1 or 2 resistors for the current limiting at rated drop voltage.






share|improve this answer





















  • This is not true, the LED strips you buy are rated for 12V, and the majority designed for a 12V DC with PWM for brightness control.
    – Jack Creasey
    34 mins ago










  • OK I'll limit the adjective
    – Tony EE rocketscientist
    4 mins ago


















up vote
0
down vote













It sounds like 12 volts is actually the 'turn-on' voltage of the LED's, so you need at least 12 volts just to get them to have dim light. By going up to 14 volts you have gone far past the point to where the LED's would be at maximum brightness. Use at least 22 gauge wire.



LED's are current driven devices, so above 12 VDC they will consume more current in a non-linear fashion such that at 14 volts you should have current limiting to protect the LED's from burning up. If they are too HOT to touch then they have too much current flowing through them.



Current limiting can be done with a power supply that sources 14 to 15 VDC and also has an adjustable current limit. Maximum brightness actually may be too bright. Inserting a 1 ohm 10 watt resistor in series with each strip will help lower the current as the resistors will dissipate the over current as heat.



With the resistors in place you can measure the DC voltage across each strip and get a better idea of the voltage the LED's will clamp hard at. Measure the voltage across the resistors to get a reading on the current consumed by each strip. They should be close. Do not force the LED's to run at a higher voltage or current then what seems like a 'comfortable' maximum brightness.



They can be warm to the touch and that means the current is at a safe long-life setting. Properly driven LED's should last 20 to 50 years. If they are 'cool' or slightly warm to touch then lifespan could be close to 50 years. Heat is their only enemy when they are in a circuit, and heat is created by current.






share|improve this answer




























    up vote
    -1
    down vote













    Your connecting wires are too thin, you are dropping voltage in your leads.



    You need to select the right size of wire and potentially use a star connection to drive the strings.



    If your strip is using SMD2835 LEDs these will be FULLY bright at 12V DC. The typical LED characteristics (when warmed up) will be as below:



    enter image description here



    Notice that the Vf is around 3.3V maximum and you will find you strip has three LEDs in series with each current limiting resistor. The LEDs visibly turn on at about 9-9.1V (low brightness). If there were 4 in series you would have to use above 12V DC to get them to turn on, and this is NOT the case.



    To select your wire size. there are plenty of charts and in the one shown below you would not use less than 16AWG wire for you application:
    enter image description here



    The leads from your power supply MUST be able to carry the full current rating. The leads from LED string to LED string could be much smaller if you used a star connection for your wiring.






    share|improve this answer





















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      4 Answers
      4






      active

      oldest

      votes








      4 Answers
      4






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes








      up vote
      1
      down vote













      From your mention of a test with a 14 volt supply, it appears that most voltage is being lost in the wires between the supply and light panel - if so, you need significantly larger wire for that connection.



      All wires have some resistance, and you must consider this resistance when determining the required wire size for a given current and cable length.






      share|improve this answer





















      • This. Also, these strips are actually fully powered at 14V not 12V, so even if wire resistance isn't an issue, they will not be as close to the rated current draw when only powered by 12V.
        – Passerby
        3 hours ago















      up vote
      1
      down vote













      From your mention of a test with a 14 volt supply, it appears that most voltage is being lost in the wires between the supply and light panel - if so, you need significantly larger wire for that connection.



      All wires have some resistance, and you must consider this resistance when determining the required wire size for a given current and cable length.






      share|improve this answer





















      • This. Also, these strips are actually fully powered at 14V not 12V, so even if wire resistance isn't an issue, they will not be as close to the rated current draw when only powered by 12V.
        – Passerby
        3 hours ago













      up vote
      1
      down vote










      up vote
      1
      down vote









      From your mention of a test with a 14 volt supply, it appears that most voltage is being lost in the wires between the supply and light panel - if so, you need significantly larger wire for that connection.



      All wires have some resistance, and you must consider this resistance when determining the required wire size for a given current and cable length.






      share|improve this answer












      From your mention of a test with a 14 volt supply, it appears that most voltage is being lost in the wires between the supply and light panel - if so, you need significantly larger wire for that connection.



      All wires have some resistance, and you must consider this resistance when determining the required wire size for a given current and cable length.







      share|improve this answer












      share|improve this answer



      share|improve this answer










      answered 4 hours ago









      Peter Bennett

      36.6k12967




      36.6k12967












      • This. Also, these strips are actually fully powered at 14V not 12V, so even if wire resistance isn't an issue, they will not be as close to the rated current draw when only powered by 12V.
        – Passerby
        3 hours ago


















      • This. Also, these strips are actually fully powered at 14V not 12V, so even if wire resistance isn't an issue, they will not be as close to the rated current draw when only powered by 12V.
        – Passerby
        3 hours ago
















      This. Also, these strips are actually fully powered at 14V not 12V, so even if wire resistance isn't an issue, they will not be as close to the rated current draw when only powered by 12V.
      – Passerby
      3 hours ago




      This. Also, these strips are actually fully powered at 14V not 12V, so even if wire resistance isn't an issue, they will not be as close to the rated current draw when only powered by 12V.
      – Passerby
      3 hours ago












      up vote
      1
      down vote













      Most 12V LEDstrips are intended for automotive use are rated at 14.2V with engine running.



      They will be dim at 9V and full brightness at 14.2 with 3 LEDs in series 1 or 2 resistors for the current limiting at rated drop voltage.






      share|improve this answer





















      • This is not true, the LED strips you buy are rated for 12V, and the majority designed for a 12V DC with PWM for brightness control.
        – Jack Creasey
        34 mins ago










      • OK I'll limit the adjective
        – Tony EE rocketscientist
        4 mins ago















      up vote
      1
      down vote













      Most 12V LEDstrips are intended for automotive use are rated at 14.2V with engine running.



      They will be dim at 9V and full brightness at 14.2 with 3 LEDs in series 1 or 2 resistors for the current limiting at rated drop voltage.






      share|improve this answer





















      • This is not true, the LED strips you buy are rated for 12V, and the majority designed for a 12V DC with PWM for brightness control.
        – Jack Creasey
        34 mins ago










      • OK I'll limit the adjective
        – Tony EE rocketscientist
        4 mins ago













      up vote
      1
      down vote










      up vote
      1
      down vote









      Most 12V LEDstrips are intended for automotive use are rated at 14.2V with engine running.



      They will be dim at 9V and full brightness at 14.2 with 3 LEDs in series 1 or 2 resistors for the current limiting at rated drop voltage.






      share|improve this answer












      Most 12V LEDstrips are intended for automotive use are rated at 14.2V with engine running.



      They will be dim at 9V and full brightness at 14.2 with 3 LEDs in series 1 or 2 resistors for the current limiting at rated drop voltage.







      share|improve this answer












      share|improve this answer



      share|improve this answer










      answered 2 hours ago









      Tony EE rocketscientist

      60.9k22192




      60.9k22192












      • This is not true, the LED strips you buy are rated for 12V, and the majority designed for a 12V DC with PWM for brightness control.
        – Jack Creasey
        34 mins ago










      • OK I'll limit the adjective
        – Tony EE rocketscientist
        4 mins ago


















      • This is not true, the LED strips you buy are rated for 12V, and the majority designed for a 12V DC with PWM for brightness control.
        – Jack Creasey
        34 mins ago










      • OK I'll limit the adjective
        – Tony EE rocketscientist
        4 mins ago
















      This is not true, the LED strips you buy are rated for 12V, and the majority designed for a 12V DC with PWM for brightness control.
      – Jack Creasey
      34 mins ago




      This is not true, the LED strips you buy are rated for 12V, and the majority designed for a 12V DC with PWM for brightness control.
      – Jack Creasey
      34 mins ago












      OK I'll limit the adjective
      – Tony EE rocketscientist
      4 mins ago




      OK I'll limit the adjective
      – Tony EE rocketscientist
      4 mins ago










      up vote
      0
      down vote













      It sounds like 12 volts is actually the 'turn-on' voltage of the LED's, so you need at least 12 volts just to get them to have dim light. By going up to 14 volts you have gone far past the point to where the LED's would be at maximum brightness. Use at least 22 gauge wire.



      LED's are current driven devices, so above 12 VDC they will consume more current in a non-linear fashion such that at 14 volts you should have current limiting to protect the LED's from burning up. If they are too HOT to touch then they have too much current flowing through them.



      Current limiting can be done with a power supply that sources 14 to 15 VDC and also has an adjustable current limit. Maximum brightness actually may be too bright. Inserting a 1 ohm 10 watt resistor in series with each strip will help lower the current as the resistors will dissipate the over current as heat.



      With the resistors in place you can measure the DC voltage across each strip and get a better idea of the voltage the LED's will clamp hard at. Measure the voltage across the resistors to get a reading on the current consumed by each strip. They should be close. Do not force the LED's to run at a higher voltage or current then what seems like a 'comfortable' maximum brightness.



      They can be warm to the touch and that means the current is at a safe long-life setting. Properly driven LED's should last 20 to 50 years. If they are 'cool' or slightly warm to touch then lifespan could be close to 50 years. Heat is their only enemy when they are in a circuit, and heat is created by current.






      share|improve this answer

























        up vote
        0
        down vote













        It sounds like 12 volts is actually the 'turn-on' voltage of the LED's, so you need at least 12 volts just to get them to have dim light. By going up to 14 volts you have gone far past the point to where the LED's would be at maximum brightness. Use at least 22 gauge wire.



        LED's are current driven devices, so above 12 VDC they will consume more current in a non-linear fashion such that at 14 volts you should have current limiting to protect the LED's from burning up. If they are too HOT to touch then they have too much current flowing through them.



        Current limiting can be done with a power supply that sources 14 to 15 VDC and also has an adjustable current limit. Maximum brightness actually may be too bright. Inserting a 1 ohm 10 watt resistor in series with each strip will help lower the current as the resistors will dissipate the over current as heat.



        With the resistors in place you can measure the DC voltage across each strip and get a better idea of the voltage the LED's will clamp hard at. Measure the voltage across the resistors to get a reading on the current consumed by each strip. They should be close. Do not force the LED's to run at a higher voltage or current then what seems like a 'comfortable' maximum brightness.



        They can be warm to the touch and that means the current is at a safe long-life setting. Properly driven LED's should last 20 to 50 years. If they are 'cool' or slightly warm to touch then lifespan could be close to 50 years. Heat is their only enemy when they are in a circuit, and heat is created by current.






        share|improve this answer























          up vote
          0
          down vote










          up vote
          0
          down vote









          It sounds like 12 volts is actually the 'turn-on' voltage of the LED's, so you need at least 12 volts just to get them to have dim light. By going up to 14 volts you have gone far past the point to where the LED's would be at maximum brightness. Use at least 22 gauge wire.



          LED's are current driven devices, so above 12 VDC they will consume more current in a non-linear fashion such that at 14 volts you should have current limiting to protect the LED's from burning up. If they are too HOT to touch then they have too much current flowing through them.



          Current limiting can be done with a power supply that sources 14 to 15 VDC and also has an adjustable current limit. Maximum brightness actually may be too bright. Inserting a 1 ohm 10 watt resistor in series with each strip will help lower the current as the resistors will dissipate the over current as heat.



          With the resistors in place you can measure the DC voltage across each strip and get a better idea of the voltage the LED's will clamp hard at. Measure the voltage across the resistors to get a reading on the current consumed by each strip. They should be close. Do not force the LED's to run at a higher voltage or current then what seems like a 'comfortable' maximum brightness.



          They can be warm to the touch and that means the current is at a safe long-life setting. Properly driven LED's should last 20 to 50 years. If they are 'cool' or slightly warm to touch then lifespan could be close to 50 years. Heat is their only enemy when they are in a circuit, and heat is created by current.






          share|improve this answer












          It sounds like 12 volts is actually the 'turn-on' voltage of the LED's, so you need at least 12 volts just to get them to have dim light. By going up to 14 volts you have gone far past the point to where the LED's would be at maximum brightness. Use at least 22 gauge wire.



          LED's are current driven devices, so above 12 VDC they will consume more current in a non-linear fashion such that at 14 volts you should have current limiting to protect the LED's from burning up. If they are too HOT to touch then they have too much current flowing through them.



          Current limiting can be done with a power supply that sources 14 to 15 VDC and also has an adjustable current limit. Maximum brightness actually may be too bright. Inserting a 1 ohm 10 watt resistor in series with each strip will help lower the current as the resistors will dissipate the over current as heat.



          With the resistors in place you can measure the DC voltage across each strip and get a better idea of the voltage the LED's will clamp hard at. Measure the voltage across the resistors to get a reading on the current consumed by each strip. They should be close. Do not force the LED's to run at a higher voltage or current then what seems like a 'comfortable' maximum brightness.



          They can be warm to the touch and that means the current is at a safe long-life setting. Properly driven LED's should last 20 to 50 years. If they are 'cool' or slightly warm to touch then lifespan could be close to 50 years. Heat is their only enemy when they are in a circuit, and heat is created by current.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 3 hours ago









          Sparky256

          10.9k21534




          10.9k21534






















              up vote
              -1
              down vote













              Your connecting wires are too thin, you are dropping voltage in your leads.



              You need to select the right size of wire and potentially use a star connection to drive the strings.



              If your strip is using SMD2835 LEDs these will be FULLY bright at 12V DC. The typical LED characteristics (when warmed up) will be as below:



              enter image description here



              Notice that the Vf is around 3.3V maximum and you will find you strip has three LEDs in series with each current limiting resistor. The LEDs visibly turn on at about 9-9.1V (low brightness). If there were 4 in series you would have to use above 12V DC to get them to turn on, and this is NOT the case.



              To select your wire size. there are plenty of charts and in the one shown below you would not use less than 16AWG wire for you application:
              enter image description here



              The leads from your power supply MUST be able to carry the full current rating. The leads from LED string to LED string could be much smaller if you used a star connection for your wiring.






              share|improve this answer

























                up vote
                -1
                down vote













                Your connecting wires are too thin, you are dropping voltage in your leads.



                You need to select the right size of wire and potentially use a star connection to drive the strings.



                If your strip is using SMD2835 LEDs these will be FULLY bright at 12V DC. The typical LED characteristics (when warmed up) will be as below:



                enter image description here



                Notice that the Vf is around 3.3V maximum and you will find you strip has three LEDs in series with each current limiting resistor. The LEDs visibly turn on at about 9-9.1V (low brightness). If there were 4 in series you would have to use above 12V DC to get them to turn on, and this is NOT the case.



                To select your wire size. there are plenty of charts and in the one shown below you would not use less than 16AWG wire for you application:
                enter image description here



                The leads from your power supply MUST be able to carry the full current rating. The leads from LED string to LED string could be much smaller if you used a star connection for your wiring.






                share|improve this answer























                  up vote
                  -1
                  down vote










                  up vote
                  -1
                  down vote









                  Your connecting wires are too thin, you are dropping voltage in your leads.



                  You need to select the right size of wire and potentially use a star connection to drive the strings.



                  If your strip is using SMD2835 LEDs these will be FULLY bright at 12V DC. The typical LED characteristics (when warmed up) will be as below:



                  enter image description here



                  Notice that the Vf is around 3.3V maximum and you will find you strip has three LEDs in series with each current limiting resistor. The LEDs visibly turn on at about 9-9.1V (low brightness). If there were 4 in series you would have to use above 12V DC to get them to turn on, and this is NOT the case.



                  To select your wire size. there are plenty of charts and in the one shown below you would not use less than 16AWG wire for you application:
                  enter image description here



                  The leads from your power supply MUST be able to carry the full current rating. The leads from LED string to LED string could be much smaller if you used a star connection for your wiring.






                  share|improve this answer












                  Your connecting wires are too thin, you are dropping voltage in your leads.



                  You need to select the right size of wire and potentially use a star connection to drive the strings.



                  If your strip is using SMD2835 LEDs these will be FULLY bright at 12V DC. The typical LED characteristics (when warmed up) will be as below:



                  enter image description here



                  Notice that the Vf is around 3.3V maximum and you will find you strip has three LEDs in series with each current limiting resistor. The LEDs visibly turn on at about 9-9.1V (low brightness). If there were 4 in series you would have to use above 12V DC to get them to turn on, and this is NOT the case.



                  To select your wire size. there are plenty of charts and in the one shown below you would not use less than 16AWG wire for you application:
                  enter image description here



                  The leads from your power supply MUST be able to carry the full current rating. The leads from LED string to LED string could be much smaller if you used a star connection for your wiring.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered 36 mins ago









                  Jack Creasey

                  13k2622




                  13k2622






















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