How far will 12volt travel?

[Richie rich]

Hi. Weird question I know..we have a man cave down the otways,with 12volt power.. But the solar panel doesn't get enough to sunlight,so I moved battery (70 amp ) and the solar panel 30mt away so it gets sunlight all day.. But it's a pain in the bum and heavy to move the battery all the time..so I was going to run cable30 mt from battery to cabin.. Will it work or will the voltage drop be to great??

[Rodnic]

It all depends how much current is being drawn and the size of the cable. There should be tables on the net showing voltage drop for cable size.
The other thing you could investigate is having the battery in the cabin and the solar panel in the sunny position. If you go this way the solar regulator should be close to the battery.

[DmaxDave]

Depends on the size cable you use.  Bigger will result in less voltage drop.

Better solution, IMHO, would be to leave battery in cabin, move the solar regulator as close as possible to the battery and run some reasonably sized cable to the solar panel.

Dave

[wintrmute]

You can convert it up to a higher voltage with a DC-DC transformer or DC-AC inverter, close to the battery.. then transform it back down again in the man cave (or just leave it at 240)
The DC-DC converters are way more efficient in conversion than most inverters I've seen though.

[OldMucks]

To draw 15 amps at that distance you need 42.4 sq. mm wire (1awg).

[DmaxDave]

To draw 15 amps at that distance you need 42.4 sq. mm wire (1awg).

Yeah but a 120W panel will only be producing around 6 amps

Dave

[OldMucks]

Probably a bit less allowing for losses.
Try 5 amps = 13.3 sq.mm (6 awg)
     10 amps = 33.6 sq.mm (2 awg)

[DmaxDave]

Plus the voltage will be 16 plus, maybe even around 20.

Dave

[buzzedman]

If you wanted to put another panel in you could also make use of a MPPT controller to minimise losses...

For my setup, I have 3 x 80W panels on my roof wired in series which gives me somewhere around 50V O.C.
My cable run is about 20M using some 8 gauge twin power cable left over from a PABX upgrade at work. My regulator is a "Victron MPPT 100|15"

I'm no guru on this - but I believe the higher voltages are subjected to less loss over long cable runs, so you are better off carrying your "Watts" with a higher voltage / low current and letting the buck converter in the MPPT regulator convert the power to a lower voltage (12V) and higher current at the end of the cable run.

Might be a setup that could help you out...

Marc.

[Richie rich]

Thanks for all your advice guys.. I'll put the battery back in cabin and run good size cable to the panel and see how it goes.. It only runs 5 led strip lights for a couple of nights.5or6 times a year.

[wintrmute]

Depending on cable length, I'd vote for leaving the battery by the panel, and transforming the power up, transmitting, then back down again.. Might be cheaper than buying such thick cable, because you can use much thinner cable at higher voltages. Or not. You do the maths.
You'd need one of each of these at each end of the cable run:

http://www.ebay.com.au/itm/DC-12V-Step-up-To-DC-48V-144W-3A-Car-Power-Waterproof-DC-DC-Converter-Regulator-/281789158759

http://www.ebay.com.au/itm/Car-Power-Supply-DC-DC-Converter-48V-Step-Down-to-12V-10A-120W-Regulator-/181199953380

Good luck!