Cable length query for solar charging

[Maxhead]

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

[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.

[Maxhead]

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

[mudski]

I'd go see your local electrical supplies like Middy's or L & H etc etc then. Are they 12V panels?

[Maxhead]

Yep 12v panels

[Winnie]

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.

[mudski]

Depends on where you go I suppose.

[the evil twin]

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

[Cuppa]

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

[Maxhead]

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