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22nd April 2014, 09:46 PM
#1
SUCH IS LIFE
Cable length query for solar charging
Guys,
I have 2x200W panels which I'm going to charge a 12v battery bank via a MPPT regulator which will be near the bank of batteries. My problem is the most efficient position for the panels is around 30-35 meters away.
Is this possible? What size cable would I need? Would I have too much voltage drop to make it worth while?
Any input would be helpful
Cheers
________________________
______ 2017 D-Max _______
I don't have a short temper. I just have a quick reaction to bullshit
WARNING: Towballs used for recoveries can, and do kill people and damage property.
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22nd April 2014 09:46 PM
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22nd April 2014, 09:57 PM
#2
Find out what they use for a house and use the same maybe? I had a quick look at the panel at my house and by the eye it looks around the 8B&S size. Wasn't hard look though. I take it the panels will be portable and not perma mounted to the ground?
Voltage drop is your issue over that distance so the heavier the better I guess.
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22nd April 2014, 10:01 PM
#3
SUCH IS LIFE
Originally Posted by
mudski
Find out what they use for a house and use the same maybe? I had a quick look at the panel at my house and by the eye it looks around the 8B&S size. Wasn't hard look though. I take it the panels will be portable and not perma mounted to the ground?
Voltage drop is your issue over that distance so the heavier the better I guess.
Cheers mate, I'm going to fix the panels permanently and only change the angle between summer and winter so I'll run the cable underground in a pipe or so
________________________
______ 2017 D-Max _______
I don't have a short temper. I just have a quick reaction to bullshit
WARNING: Towballs used for recoveries can, and do kill people and damage property.
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22nd April 2014, 10:35 PM
#4
I'd go see your local electrical supplies like Middy's or L & H etc etc then. Are they 12V panels?
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The Following User Says Thank You to mudski For This Useful Post:
Maxhead (22nd April 2014)
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22nd April 2014, 10:39 PM
#5
SUCH IS LIFE
________________________
______ 2017 D-Max _______
I don't have a short temper. I just have a quick reaction to bullshit
WARNING: Towballs used for recoveries can, and do kill people and damage property.
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22nd April 2014, 10:44 PM
#6
The 747
Originally Posted by
mudski
I'd go see your local electrical supplies like Middy's or L & H etc etc then. Are they 12V panels?
They won't help... Nothing shit's me more than when people come in and tell me their application and ask what cable they need. I am not an electrician and I do not know the answer. Even if I did I am not allowed to tell them. I know a few blokes though Kris if I see them I'll ask the question.
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The Following User Says Thank You to Winnie For This Useful Post:
Maxhead (23rd April 2014)
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22nd April 2014, 11:08 PM
#7
Depends on where you go I suppose.
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22nd April 2014, 11:18 PM
#8
I am he, fear me
Originally Posted by
Nisshead
Guys,
I have 2x200W panels which I'm going to charge a 12v battery bank via a MPPT regulator which will be near the bank of batteries. My problem is the most efficient position for the panels is around 30-35 meters away.
Is this possible? What size cable would I need? Would I have too much voltage drop to make it worth while?
Any input would be helpful
Cheers
Yowser dude... you are going to need some serious cable. 8 B&S is too small for a 12 volt system and will drop over 20%.
400 Watts (or nearly 1/2 a kilowatt) of 12 Volt nominal Solar Panel array is going to supply maybe 25 amps at peak Solar.
25 Amps even thru 6 B&S is going to drop 10% or more over that distance and that much 6 B&S will cost you over $400 incl terminations.
Depends what you are wanting to do whether it makes it worthwhile
Dolphins are so smart that within a few weeks of captivity, they can train people to stand on the very edge of the pool and throw them fish.
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The Following User Says Thank You to the evil twin For This Useful Post:
Maxhead (23rd April 2014)
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23rd April 2014, 12:48 AM
#9
Travelling Podologist
I’m not sure what size cable you would need, but it would be seriously heavy & seriously expensive, costing more than the rest of the system combined by quite a margin, so unlikely to be an economic proposition. Cheaper to connect the panels in series to give 24v & use an mppt regulator capable of taking 24v input to charge the batteries at 12v. This will allow the use of lighter cable but even then the cable is likely to cost a lot, although if you can pick up some secondhand welding cable you may be able to keep the costs within ‘manageable’ limits.
This link to a cable sizing calculator should help. http://www.solar-wind.co.uk/cable-sizing-DC-cables.html Base your calculations on 25 amps as ET suggests & have a play around with the other parameters.
Far better if you can find a way of siting the panels much closer to the batteries.
Cuppa
2006 4.2TDi ex-Telstra Remote area Camper. 425w roof mounted solar, 360Ah Aux batts, BCDC1240, Onboard hot & cold pressurised & filtered water, (25 litre hot water calorifier), ARB fridge, ARB freezer, Built in kitchen, heaps of easy access storage, 240v, 3” Genie exhaust + dynotune, 2” lift, 3900kg GVM upgrade, second glovebox, ROH Blaktrak steel wheels, Bridgestone D697's (now Toyo RT's), Redarc gauges/pillarpod, Hema HX-1, Icom 450 CB, dual rear view cameras, Onboard 30amp Victron mains charger, second glovebox, dual seat conversion, TPMS, Boss PX7 onboard air with 9 litre tank, 350w inverter, Steel bullbar, Harrop Eaton diff lock (front), Warn winch, Snorkel, Dual spares , 160 litre water tank, 180 litre fuel in two tanks (approx 1200km range) 2010 Tvan Tanami. (incl another 70 litre water tank) with matching wheels/tyres (& 3rd spare)
A Nomadic Life (Blog)
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23rd April 2014, 05:50 AM
#10
SUCH IS LIFE
Hmm, I thought this might not be an easy or cheap solution.
I want to charge 2x120ah DC batteries which I currently have in parallel giving me 240ah. As my needs increase I could add another 120 maybe.
As all my lighting and appliances are 12v so I wanted to leave the system at 12v.
My regulator is capable of 12/24v so I could in fact turn it into a 24v system but I can still see losses here
My best option i think is to put the panels closer and have limited sunlight, I think this would still be plenty to charge 240ah with 400w.
This is for my shack out bush so it will only get used on weekends and holidays so no big or extended power draws will be required and a lot of time in between for charging.
Unfortunately, there are a couple of gums on the northern side of it making it hard but I still think I could get a decent ammount of sun.
The only other solution is a wind turbine but that's more cost when I already have the panels and batterues
Last edited by Maxhead; 23rd April 2014 at 06:00 AM.
________________________
______ 2017 D-Max _______
I don't have a short temper. I just have a quick reaction to bullshit
WARNING: Towballs used for recoveries can, and do kill people and damage property.
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