Compensating Voltage Drop on 100m Cable for 12V 5W Receiver: Power Supply Selection

Hello,
The topic has been rolled out many times on the forum but I did not find a discussion like "what's better".
I have a 12V 5W receiver at the end of a 100m long cable (twisted conductor cross-section approx. 0.5mm2, measured resistance 26? . During the first attempt - powered by a 12V 3A power supply, the voltage drop turned out to be too high and the receiver does not respond. I searched the calculator on the PRS website ( link ) which shows that I have a voltage drop of 24%. I think it is too much, although I do not fully understand why, because with a 3A power supply I should still have a lot of reserve even with such a voltage drop.
Anyway, I have two ideas on how to get out of it, maybe both are wrong, so I'm asking

1) Increase the power of the 12V power supply until you manage to compensate for the voltage drop caused by a long cable - here's a question immediately - how to calculate the power of such a power supply?

2) Use a power supply with higher voltage, eg 24V, and finally, in front of the receiver, insert the converter. For 24V, with the described cable and receiver parameters, a voltage drop of 6% comes out, so it should be OK?

Personally, I am inclined to the solution No. 2. I know that it would be best to let go of 230V and give the power supply at the end, but this solution comes off immediately for several reasons, the most important of which is that the receiver will be buried underground and I am afraid of possible short circuits and the consequences of related. Besides, it seems safer to make the whole installation on DC 12/24 V than on 230V AC. If it matters, the receiver (receivers) will be solenoid valves and the matter concerns the automatic garden watering system.
Thanks in advance for your help and advice

Calculations show that the power supply should have 22.83V in these conditions.

Hello.

How did you calculate from your link that you have a decrease of 24%. Since at 1mm2 there is 100% voltage drop at 5A.



Give 24V or 48V but AC and finally a power supply or converter.

dasej wrote:

How did you calculate from your link that you have a decrease of 24%. Since at 1mm2 there is 100% voltage drop at 5A.

Why are you putting 5A? You do not know the actual current consumption of the receivers, they are probably much lower than the permissible current of the power supply (3A).

I use a regulated power supply for such solutions and turn it up until the voltage suits me, but for the solenoid valves in the garden I run 24v variable and these are also solenoids.

dasej wrote:

How did you calculate from your link that you have a decrease of 24%. Since at 1mm2 there is 100% voltage drop at 5A.

I put 0.42A or 5W of power. It comes out 12% at 1mm2 at 0.5mm2 is twice as much, i.e. 24%

dasej wrote:

Give 24V or 48V but AC and finally a power supply or converter.

A valuable note - jump from DC to AC but stay low voltage. For alternating current, the voltage drops are smaller, I understand correctly?
Thanks

Added after 2 [minutes]:

guciq wrote:

I use a regulated power supply for such solutions and turn it up until the voltage suits me, but for the solenoid valves in the garden I run 24v variable and these are also solenoids.

I just checked that using DC 24V and the converter at the end did the trick with 100m of cable.
If I did everything from scratch, I would probably do as you wrote, but unfortunately I have already bought 12V DC solenoid valves and it's a pity to throw them away just
And out of curiosity - how did you insulate the connections underground? Some resin or ordinary electrical tape?

a small bottle flooded with resin

Eventually, I used a 24V power supply, and with each receiver (there were several, at different distances from the power supply) I inserted the LM7812 stabilizer. Additionally, I had to screw a large heat sink to the stabilizer - a steel flat bar with dimensions of approx. 5x7 cm thick. 4mm. The heat sink was necessary, because a lot of heat was generated at the receivers close to the power supply (15-20m), and I wanted to avoid installing converters due to the unfavorable conditions in which it is to operate - buried underground.