So I am wiring garden lighting over a distance of about 30m. Doing the math, if I use 4.1mm cross-section cable, I will get somewhere in the 11.9v range. Using LED lighting, I am afraid of lumen loss and want to boost the voltage up to mid-12's and that way the 0.1v loss will be ok. Is this sound thinking?

Beyond this, I can't find any information on Amperage loss. If I need 7A and I use a power supply rated at 8A, will it be sufficient? Or will it not be able to supply the full amount at such a distance?

 

hi shezza,
I don't think you will see any noticeable difference in LED brightness when operating at 11.9V instead of 12V.
You need to calculate the loop resistance of the 30mtr cable, ie: from the supply to the LED lamp and back to the supply.
This will enable you to calculate the voltage drop in any cable length.
E
EDIT:
An example
You can find the type and resistance of the cable conductor on line.
https://chemandy.com/calculators/round-wire-resistance-calculator.htm

 

It's always best to run led lights well below their recommended voltage , they will be more efficient (lumens /W) and last much longer , and you will hardly notice the loss of light ..

I run 12V strips at around 11.5V

 

You can find the type and resistance of the cable conductor on line.
https://chemandy.com/calculators/round-wire-resistance-calculator.htm

Nice find.

ak

 

If I need 7A and I use a power supply rated at 8A, will it be sufficient? Or will it not be able to supply the full amount at such a distance?

The supply does not know how far the current is going. Any drop in current is due to the increased resistance of the wire, not the inability of the power supply to push current over a longer distance.

Bob

 

Thank you for all the replies. I did get the led strip since making this post, was able to run them as low as 11.5 and that gives me a lot of buffer.