Running a long wire

[backwoods]

digging in woods sucks but a mattocks is your friend as you probably know.
Or rent a ditch witch if possible. It's the right way to do it if it's going to be long term.
Rodents like to chew on wires also. Is your dad going to help dig the trench? haha If he had to do the work he might reconsider
a move that far.

 

[dmh]

Hello, I've been tasked with running a very long wire from my solar panels to my camper and I'm just trying to figure out if it's possible within some sort of reasonable price. I am going to order 9, 250-watt panels and do them in 3s3p and I've essentially been tasked to run a wire to the 300 feet back into the woods where my dad wants to put our camper. These are the panels we'll be getting: https://store.santansolar.com/product/santan-solar-t-series-250w-snail-trails/ I'm sure the specifications will be important. I used a solar wire calculator from Renogy and it recommended 4 gauge wire but I have no idea where I would even find 300 feet of 4 gauge wire and please correct me if I'm wrong but, doesn't the wire need to be rated for PV? I tried looking and couldn't find anything that long over 8 gauge. I mean is there another way I can wire these panels to use a less expensive gauge or am I completely misunderstanding something because it looks pretty hopeless. My dad is extremely, well, persistent, and he wants to move the camper from 50~ feet from the panels to all the way in the back of our property for more privacy and I don't know if I'll be able to change his mind on it. Can you guys help me out?

Put the inverter at the panels...

 

[Scixxor]

They exist, but are very expensive in my opinion.

Don't connect solid wire to the charge controller.
You can change it over to stranded wire, before connecting.

If you haven't purchased anything, you might consider going with a 48v battery system. The AIO's generally are setup for a higher solar voltage.

Yeah if I had the option right now I would go with a 48volt system but I already have 2 12volt batteries and an all-in-one that only accepts 24 volts

 

[Scixxor]

Put the inverter at the panels...

It's not that easy for me, I have an all-in-one charger/inverter so I would also need the batteries there, neither my batteries nor my all-in-one will work below freezing and this winter alone it was almost always below freezing with lows of 1°. Using a heater to keep them warm would use a lot of my solar power and just not really work.

 

[Scixxor]

digging in woods sucks but a mattocks is your friend as you probably know.
Or rent a ditch witch if possible. It's the right way to do it if it's going to be long term.
Rodents like to chew on wires also. Is your dad going to help dig the trench? haha If he had to do the work he might reconsider
a move that far.

Yeah, I discussed the idea with my dad and he said there's no way in hell he's digging through all that wood so it would be completely up to me to do it if that's the option I decided to do. I've never heard of a ditch witch but if it's not too expensive it could make things much more doable. We do have a neighbor with a small excavator which could be a nice option.

 

[Hedges]

Inverter at panels only works if voltage drop on AC is acceptable. Not good for surge loads like starting a motor.
I favor voltage drop in PV wires, because it is only efficiency loss nothing else unless voltage drops below MPPT minimum. 20% or 50% drop can be tolerable, it is just a trade off of Si cost vs. Cu.

What you would like is as high DC as possible, like 380 Vmp. I get that with GT PV inverters because they have 600 Voc limit. The 380 Vmp is fairly ideal for generating 240 Vrms.

For your SCC, there are 250V Midnight Classic and a 600V from (Schneider? Morningstar?) but expensive. Victron has some higher voltage models, also expensive.

Ditch Witch is a chain digger. You can rent a small one meant for sprinkler pipes. Much faster than digging with an excavator/backhoe bucket. Unless you're hitting rock or roots.

PVC conduit laid on the surface would be a (non code compliant) easy alternative. If pulling wire is difficult, instead roll out wire on ground and slip each length of conduit over it before gluing.

 

[Scixxor]

3S/3P gives ~110V DC.
That is a killer voltage that can draw very long sparks. You will have to very carefully chose your breakers !
Or be very cautious to cover your panels before unplugging.

Yes it is, I currently have 5 100-watt panels all in series for about that same voltage, thankfully I bought an all-in-one which is rated for up to 145 VOC and has the appropriate breakers.

 

[12VoltInstalls]

bought an all-in-one which is rated for up to 145 VOC and has the appropriate breakers.

What model / brand?

what's UF?

Underground Feeder. It’s gray, has solid sheathing ‘cast’ over the conductors, no paper liner

Plus burying 300+ feet of cable would take an extremely long time.

Actually it won’t be bad if done a bit at a time. An axe, spade, mattock or pick-axe, and a 60” pinch bar. Do 75 minutes a night. I’m guessing like 20-40’ feet a night; in two weeks you’ll be done.

My first ‘camper setup’ 25 years back was 20’ of sewer ditch 5’ down and 50’ of electrical ditch (10ga UF) 24” down. Done in less than a day including connecting wiring and glueing 4” pvc sewer, etc.

I would use 10 awg and accept 18% loss due to IR drop.
I've been known to unroll UF directly on the ground. Not saying that is to code or anything ...

You can also orient each 3s differently, reducing peak current and loss.

Ya, if the 8ga is affordable to you that could be better.

I like facing arrays to better spread sun max over the day. Once I thought it was a good idea, might give a little. Then I tried it and I was surprised at the difference.
In your case it has a different additional usefulness, too.

something with a higher voltage

Victron does a 40A SCC for 250V input for about $650. You could still run your AIO but use the Vic for charging if you upgrade next year - but I’d probably buy another string of panels first - but that’s just me.

 

[12VoltInstalls]

neither my batteries nor my all-in-one will work below freezing and this winter alone it was almost always below freezing with lows of 1°. Using a heater to keep them warm would use a lot of my solar power and just not really work.

That’s wise

Aren’t your batteries flooded lead acid?

Mine worked fine as low as 28*F last winter. Have them outside.

 

[backwoods]

if you got money , another option is one of those invasive-less tunnelers. They use them to run pipeline
for water/gas. It bores the tunnel as it lays the pipe, I'm not sure the largest diameter it can do but it can at least do 2" pipe.
They run tracer wire along with the pipe so they know where it is underground as it bores. I don't think roots will cause too much issues with it.
Big rocks may but it can go around them. I never used one of these only have seen them in action but I bet you could probably even attach wire
inside the pipe and let it run out as the pipe is ran. This way you already have a fish wire to pull wires thru.
edited to add, I'm not sure if the machine can get to where you need it go so it may not even be feasible.

 

[12VoltInstalls]

if you got money

The borers are expensive to hire.

 

[740GLE]

You could use Triplex wire overhead. Same wire as the utility companies use to run overhead from their poles to houses.

People on this site are afraid of aluminum conductor for some odd reason.

While this is probably the cheapest and quickest method of running cable 300ft.

 

[Scixxor]

What model / brand?


Underground Feeder. It’s gray, has solid sheathing ‘cast’ over the conductors, no paper liner


Actually it won’t be bad if done a bit at a time. An axe, spade, mattock or pick-axe, and a 60” pinch bar. Do 75 minutes a night. I’m guessing like 20-40’ feet a night; in two weeks you’ll be done.

My first ‘camper setup’ 25 years back was 20’ of sewer ditch 5’ down and 50’ of electrical ditch (10ga UF) 24” down. Done in less than a day including connecting wiring and glueing 4” pvc sewer, etc.



Ya, if the 8ga is affordable to you that could be better.

I like facing arrays to better spread sun max over the day. Once I thought it was a good idea, might give a little. Then I tried it and I was surprised at the difference.
In your case it has a different additional usefulness, too.

Victron does a 40A SCC for 250V input for about $650. You could still run your AIO but use the Vic for charging if you upgrade next year - but I’d probably buy another string of panels first - but that’s just me.

Hello again, I was hoping to see you here! Your input is extremely helpful and after talking everything over with my dad I think I'm going to bury the wire as you suggested. My all-in-one is this: http://watts247.com/product/pip-lv2424-msd/?wpam_id=3 I'll probably just bury 6 gauge wire, I've heard some people talk about a conduit I'm assuming this is just something you're put your wire in like PVC pipe, is this correct? This is the wire I found after hearing other people recommend it: https://www.wireandcableyourway.com/6-awg-thhn-building-wire do you think this will work? Just getting 325 feet of red and 325 feet of black? I would buy another string of panels but my all-in-one has a max of 2000 watts of solar so I'm already going to be over paneling by 13%~

 

[rhino]

Just throwing out other ideas.. My panels are 500 to 600ft away and I used 4 AWG aluminum which attaches to combiner boxes at the arrays and a power block near the charge controller at the other end. Power block allows you then to run whatever necessary gauge copper cable to the charge controller. Also used large continuous rolls of HDPE conduit with pull tape which was cheaper (if you order enough, and is more environmentally friendly than PVC) from Chapman Electric. My charge controllers are Victron 250V versions.

 

[rin67630]

People on this site are afraid of aluminum conductor for some odd reason.
While this is probably the cheapest and quickest method of running cable 300ft.

And copper prices are running through the ceiling.
Soon, you will buy copper by the ounce at the stock exchange...

 

[740GLE]

Hello again, I was hoping to see you here! Your input is extremely helpful and after talking everything over with my dad I think I'm going to bury the wire as you suggested. My all-in-one is this: http://watts247.com/product/pip-lv2424-msd/?wpam_id=3 I'll probably just bury 6 gauge wire, I've heard some people talk about a conduit I'm assuming this is just something you're put your wire in like PVC pipe, is this correct? This is the wire I found after hearing other people recommend it: https://www.wireandcableyourway.com/6-awg-thhn-building-wire do you think this will work? Just getting 325 feet of red and 325 feet of black? I would buy another string of panels but my all-in-one has a max of 2000 watts of solar so I'm already going to be over paneling by 13%~

Why not this?

6-6 Claflin Aluminum Duplex URD Direct Burial Cable

600V Underground Distribution Cable. Sold by the foot.

www.wireandcableyourway.com

Much more economical

 

[Scixxor]

Why not this?

6-6 Claflin Aluminum Duplex URD Direct Burial Cable

600V Underground Distribution Cable. Sold by the foot.

www.wireandcableyourway.com

Much more economical

Hello, I honestly don't know much about aluminum wire is this better than the copper stuff I linked? Because if not the stuff I linked is $1.06 per foot why what you linked is $1.28 per foot.

 

[Scixxor]

Why not this?

6-6 Claflin Aluminum Duplex URD Direct Burial Cable

600V Underground Distribution Cable. Sold by the foot.

www.wireandcableyourway.com

Much more economical

Hello, I honestly don't know much about aluminum wire is this better than the copper stuff I linked? Because if not the stuff I linked is $1.06 per foot why what you linked is $1.28 per foot.

 

[timselectric]

Hello, I honestly don't know much about aluminum wire is this better than the copper stuff I linked? Because if not the stuff I linked is $1.06 per foot why what you linked is $1.28 per foot.

With aluminum, you need to go up one size for the rated amperage.
Don't forget to include the cost of conduit.
URD doesn't require a conduit.
Also, the URD includes both conductors at that per ft price.

 

[740GLE]

Hello, I honestly don't know much about aluminum wire is this better than the copper stuff I linked? Because if not the stuff I linked is $1.06 per foot why what you linked is $1.28 per foot.

As Tim mentioned, that’s two conductors, so only one run is needed, not two of the thhn you listed, so yeah it’s almost half as expensive.

The other thing to consider is ground conductor which would covered if you picked up triplex as mentioned before.