Continuing on from the power injection testing, i thought it might be useful to look at a string of 50 seed pixels
This is a random grab from the ones i have.
All measurements are for 100% brightness, base reading are at 5v, input was raised up to 5.5v for each test to confirm constant current was being used.
Measured the voltage drop on the approx 10 foot of lamp flex from the power supply to the pixel input, it was not negligible and accounted for @ 0.3v drop for white
For 50 Seed Pixels - with voltage end feed
Red at 5v - 280mA, 260mA @ 3.6v
Green at 5v - 280mA, 260mA @ 3.9v
Blue at 5v - 280mA, 260ma @ 3.9v
White at 5v - 740mA, 720mA @ 4.1v
Red 5.6mA per pixel CC
Grn 5.6mA per pixel CC
Blue 5.6mA per pixel CC
White 14.8mA per pixel CC
All four were tested up to 5.5v input with no change to the current draw at 5v
The end voltage on white was a very consistent 1.1v under the input voltage
Colours consistent got 0.4v under
At 100% white plugging another 50 you are already starting under the min voltage required for proper operation.
So end voltages are
100% - 3.93v
90% - 4.03v
80% - 4.13v
70% - 4.23v
60% - 4.33v
50% - 4.44v
40% - 4.54v
30% - 4.64v
20% - 4.74v
Seems that around 50% to 60% you can easy run 100 from one input at 5v. You can get the same at 70% by running the string slightly hot at 5.3v
If you center feed the voltage into the middle of a 100 pixel string you get the same performance 50 pixels each way.
!00% white - 50 pixels, the scope is looking a fraction of the outgoing 2811 data stream
Cheers
Phil
Power Injection testing using multiple PSU's
Let's get some housekeeping for this thread out of the road first. Opinions don't count nor does the this is how it's always been done. Contribute with questions. Contribute with you own experiments. Feel free to ask me to test combinations. do NOT EVER connect two power supplies together at...
auschristmaslighting.com
This is a random grab from the ones i have.
All measurements are for 100% brightness, base reading are at 5v, input was raised up to 5.5v for each test to confirm constant current was being used.
Measured the voltage drop on the approx 10 foot of lamp flex from the power supply to the pixel input, it was not negligible and accounted for @ 0.3v drop for white
For 50 Seed Pixels - with voltage end feed
Red at 5v - 280mA, 260mA @ 3.6v
Green at 5v - 280mA, 260mA @ 3.9v
Blue at 5v - 280mA, 260ma @ 3.9v
White at 5v - 740mA, 720mA @ 4.1v
Red 5.6mA per pixel CC
Grn 5.6mA per pixel CC
Blue 5.6mA per pixel CC
White 14.8mA per pixel CC
All four were tested up to 5.5v input with no change to the current draw at 5v
The end voltage on white was a very consistent 1.1v under the input voltage
Colours consistent got 0.4v under
At 100% white plugging another 50 you are already starting under the min voltage required for proper operation.
So end voltages are
100% - 3.93v
90% - 4.03v
80% - 4.13v
70% - 4.23v
60% - 4.33v
50% - 4.44v
40% - 4.54v
30% - 4.64v
20% - 4.74v
Seems that around 50% to 60% you can easy run 100 from one input at 5v. You can get the same at 70% by running the string slightly hot at 5.3v
If you center feed the voltage into the middle of a 100 pixel string you get the same performance 50 pixels each way.
!00% white - 50 pixels, the scope is looking a fraction of the outgoing 2811 data stream
Cheers
Phil
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