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I have purchased a variable bench power supply 0-30 volts and 0-10 amps. I intend buy and to connect this supply to a suitable dc power distribution board, from which I wish to power four led matrix panels which operate at 5 volts per panel, and consume between 5 and 10 amps depending on the number of leds which are lit at any one time. I don't know what settings I should select on the bench power supply. Should I select 5 volts or ( 5 x 4), 20 volts ?. Is the capacity of the bench supply at 10 amps inadequate for this project ? I can limit the number of leds which are lit at any one time, via my Arduino Mega and suitable coding.

Nigel Liddicoat
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If your led strips are 5V, than you should set the power supply to 5V. Only amps are 'divided' when using a parallel circuit.

If you have 10A supply, and each panel uses 10A than it's not enough. But 10A per panel is a lot.

Michel Keijzers
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    Hi Michel, Thank you for your response to my question. I now know the voltage setting. Yes 10A per panel is a lot, but only when all 256 leds are lit at the same time. I will need to write some code to limit the number of panels which are "on" at the same time and the number of leds which are lit at the same time. Bye for now. – Nigel Liddicoat Apr 10 '18 at 12:00
  • Still seems a lot .. normal leds use 20 mA per color (R, G, B), so 60 mA, times the number of leds. – Michel Keijzers Apr 10 '18 at 13:00
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    Hi Michel, Yes I agree, still seems a lot. I will check the led matrix specification on the manufacturer's web site. I think there are 256 leds per panel. If it all goes wrong there is a circuit protection cut out on the bench supply, but I would rather not reply on that option !! – Nigel Liddicoat Apr 10 '18 at 13:08
  • Than 256 leds * 0.06 A = 15.36 A ... so maybe it's correct (assuming each led is not 20 mA but a bit less.... on the other hand, a power supply should have some 'reserve'. – Michel Keijzers Apr 10 '18 at 13:09
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    Hi Michel, Well my information and your calculation appears to correspond. We could well be looking at a very max of just over 15 amps, per panel. Perhaps I should have bought a bigger power supply !! or one for each panel !! Being a novice is just not fun !! Maybe I need to re-think the whole project. Mnay thank for your advice which has been most informative. – Nigel Liddicoat Apr 10 '18 at 14:03
  • I'm a novice myself too ... I also was surprised when I bought a simple LED (60 LEDs) it uses 15 W. And I bought also lots of components that I never used, to find out they were not what I needed. But iti's a good learnign experience, and hopefully sooner or later I use the unused components anyway for something else. – Michel Keijzers Apr 10 '18 at 14:06
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    Hi Michel, I am glad to hear that I am not the only one making silly mistakes and wasting money on redundant components does reinforce the learning experience, as my brain remembers the financial cost !! Bye for now. – Nigel Liddicoat Apr 10 '18 at 14:19
  • What might help is to start with small / cheap components. – Michel Keijzers Apr 10 '18 at 14:20
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    Hi Michel, Yes point taken. My problem is that I tend to run before I can walk, so there are often unintended consequences, as with this project. I'm off out now for some fresh air, but I will be in touch again if that is OK. – Nigel Liddicoat Apr 10 '18 at 14:27
  • No problem at all .. I am busy with my first project still after one year, and already removed some aspects, and in the meantime made some smaller things. I'm a software engineer without electronics knowledge when started but I'm gradually gaining some. – Michel Keijzers Apr 10 '18 at 14:30