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please have a look at this chart:

LED Strip - Parallel

I have a question on the calculation of voltage drop on each of the connection point between the wire and led strip. We are using 1.5mm2 wire and 24V led strip which uses 0.6A per meter.

Do we calculate the voltage drop for the first strip using 0.6A or 8.4A (the total current of all the strips)?

How about the second strip? Do we calculate the voltage drop based on 1.5A, 8.4A or (8.4A - 0.6A = 7.8A)?

Similarly, for the second last strip, do we calculate the voltage drop based on 2.1A or (8.4A - 0.6A - 1.5A - 1.8A = 4.5A)?

Thank you.

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  • \$\begingroup\$ 24V and 8.4 Amps on 16 AWG will see a 10% or 2.2V droop at the 10 meter point. You may want to consider a larger gauge wire for that section, or put the power supply closer. \$\endgroup\$
    – Passerby
    Jun 24 '19 at 0:35
  • \$\begingroup\$ Or adjust it as I do. In your case 26.2V as above \$\endgroup\$ Jun 24 '19 at 1:27
  • \$\begingroup\$ The wires have been buried so i would want to avoid changing wires if possible. Will using 26.2V on a 24V led strip cause damage though? Since the led strip may sometimes run at 50% of the rated maximum power hence the voltage drop may be lower due to lowered current and a voltage higher than 24V may end up feeding the led strip? Or should i increase only a little (25V for eg) in order to accommodate for the said problem and also for the voltage drop to stay within 5% in both 50% and 100% power usage? \$\endgroup\$
    – HA E
    Jun 25 '19 at 10:21
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The voltage drop in a segment the supply wiring depends on the current in that segment.

The current in the segment from the supply to the top LED strip will carry the full 8.4 Amp, so you would use that current to calculate the voltage drop in that segment.

The 0.3 m to the second strip will only carry 7.8 Amp, and so on down the system.

The voltage drops in the 0.3 m segments between the strips may be small enough to ignore (I don't use metric wire, so haven't done the calculations).

The voltage at the input to the last strip will be the sum of voltage drops in all the wire segments feeding it.

There will also be voltage drops along the LED strips - you may want to run wires to the mid-point and far end of the longer strips to reduce that voltage drop.

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