Where to put the inverter?

[RickStarr]

My panels are 250 feet from where the power (110v) is to be delivered. Should I place the inverters closest to the panels, or closest to the final destination to avoid line loss, overheat, etc. Either inverter location is equal: indoors, sheltered, etc.

Inverter should be closer to the panels.

Inverter should be closer to the final plug.

 

[SeaGal]

IMHO, best to run PV cables the distance and have inverter nearer the house. For 2 reasons...

a) less losses (as PV DC connection will be at higher voltage than 110V AC) &
b) no issues with AC voltage drop when large load is turned on.

 

[hwy17]

If it's a hybrid off grid system you want the inverter at the house to avoid having to run AC there and back to the array.

If it's a grid tied only system it's a less clear decision. The NEC gives a lot more options and standardized treatment for AC wiring. So it becomes common to put string inverters at the array and then run a large feeder to the house. You can even use aluminum wire.

 

[Steve_S]

DC Wire runs should be as short as possible.
That means wiring from the Panels (DC) to Solar Controller as line losses will add up quickly.
Batteries to Inverter/Charger should also be as close as possible.
VAC does NOT suffer line losses like DC. You can easily run 120VAC 250 feet provided you run the right wire for the amperage etc.

There are many options possible and dependent on your location. Many people who have the space, will build a "Power House" to contain all the solar gear (Solar Controllers, Inverter/Chargers, Batteries) and then just run AC wire to the destination(s). The most common method is to run NMWU AC Wire underground to the Target structure.

TIP !
You CANNOT use solid core copper wire (as used or AC wiring) for DC, Stranded copper is necessary and rated for the amperage it will handle.
If you live in an area that is subject to COLD, note that you cannot charge LFP Batteries below 32F/0C but they can discharge until -20C. Batteries themselves can be "warmed" or an external heating system may be used to keep the "Power House" above 15C/77F.

 

[RickStarr]

Quick answers (and contradictory, big surprise) so far. House is a very long basement rancher. Panels at one end of the house, garage at the other. Electron path has to go up 2 floors (panels cantilevered off deck), back down to basement, across 100 ft of house, up garage walls, over ceiling, and back down the other side. Total run ~250 ft. Either inverter location inside, in garage power to be used to run appliance(s), charge battery, etc. Variable uses, some AC, some DC unfortunately. Live in Tennessee; garage temp never below 40. AC run would be 10/2, don’t know if it was a DC run, I still have to confirm sizing. [No grid tie, completely gapped from grid.] Thanks for responses so far. Still figuring out the optimum design. Running it is going to be a bitch, I know, but I’ve done worse. Well, not worse but equivalent.

 

[Bop]

DC Wire runs should be as short as possible.
That means wiring from the Panels (DC) to Solar Controller as line losses will add up quickly.
Batteries to Inverter/Charger should also be as close as possible.
VAC does NOT suffer line losses like DC. You can easily run 120VAC 250 feet provided you run the right wire for the amperage etc.

There are many options possible and dependent on your location. Many people who have the space, will build a "Power House" to contain all the solar gear (Solar Controllers, Inverter/Chargers, Batteries) and then just run AC wire to the destination(s). The most common method is to run NMWU AC Wire underground to the Target structure.

TIP !
You CANNOT use solid core copper wire (as used or AC wiring) for DC, Stranded copper is necessary and rated for the amperage it will handle.
If you live in an area that is subject to COLD, note that you cannot charge LFP Batteries below 32F/0C but they can discharge until -20C. Batteries themselves can be "warmed" or an external heating system may be used to keep the "Power House" above 15C/77F.

Depends, many hybrid and even offgrid inverters these days run DC voltages at 250VDC and above, 450VDC isn't uncommon, in which case your losses on the DC side are far less than on the AC side for the same sized cable (especially if you are in one of the few countries still running '120v' nominal mains)- in which case it makes sense to have the inverter and battery bank as close as possible to the house, minimising the 'high loss' AC side...
Same with inverter battery banks- run as high as possible battery bank voltage to minimise copper losses and cabling costs- here in Ozzieland, 48v is dead as a dodo- most are 72v, with many newer installs running at 96v or higher (indeed my own '48v, 12kw' hybrid inverter (250VDC PVmax input rating) was bought as 'old stock' because so few use 48v these days... its current replacement for new build use is a 96v 15kw unit!!!)

 

[DougfromdaUP]

You CANNOT use solid core copper wire (as used or AC wiring) for DC, Stranded copper is necessary and rated for the amperage it will handle.

Why is this?

 

[Partimewages]

Each case is unique. You will need to see what your equipment specifications are for the correct decision.
Higher voltage for longer runs is nearly always desirable.

 

[Subdood]

Why is this?

I'm curious as well. Why wouldn't a 10 awg solid wire work compared to 10 awg stranded. As long as the wire is rated to handle the voltage and current I don't see a problem. The THWN I've seen is rated to 600V, so either should be okay for runs from PV arrays.

 

[Bop]

Sounds like one of those 'funny US rules' made up for no apparent reason...
In Australia the use of either solid or stranded core feed cables is allowable in fixed installations under AS/NZS 5033- it has to be double insulated, with the inner insulation a contrasting colour to the exterior insulation, and be rated at 1000VDC (up from the previous 600VDC under the old 2014 standard)- older systems are 'grandfathered' in, but new gridtie or hybrid installs have to use compliant and tested cables (by Australian Standards or other approved standards organisation)- ironically enough the UL is not an accepted organisation for Au/NZ standards and anything with a UL listing has to be tested by an approved organisation before allowing to be used...

 

[Nobodybusiness]

Quick answers (and contradictory, big surprise) so far. House is a very long basement rancher. Panels at one end of the house, garage at the other. Electron path has to go up 2 floors (panels cantilevered off deck), back down to basement, across 100 ft of house, up garage walls, over ceiling, and back down the other side. Total run ~250 ft. Either inverter location inside, in garage power to be used to run appliance(s), charge battery, etc. Variable uses, some AC, some DC unfortunately. Live in Tennessee; garage temp never below 40. AC run would be 10/2, don’t know if it was a DC run, I still have to confirm sizing. [No grid tie, completely gapped from grid.] Thanks for responses so far. Still figuring out the optimum design. Running it is going to be a bitch, I know, but I’ve done worse. Well, not worse but equivalent.

I noticed the contradictory answers also.
Can tell you my inverters sit in a building 250 feet from array and 250 ft from the house..

Ran 8 Gauge from Array to inverters.
Ran 4/0 aluminum from inverters to house.

Not had any issues.

 

[Bop]

I noticed the contradictory answers also.
Can tell you my inverters sit in a building 250 feet from array and 250 ft from the house..

Ran 8 Gauge from Array to inverters.
Ran 4/0 aluminum from inverters to house.

Not had any issues.

Depends entirely on the PV voltage- if it is an old fashioned system with low voltage PV arrays, then obviously the cables from the PV array to the inverter need to be thicker than the mains cables and the inverter is best sited near the array (as the current is higher for the same wattage), but with many modern systems having the PV voltage higher than the mains, then the mains cable needs to be thicker than the array cable (and the inverter is best sited near the house)
It all depends entirely on your specific equipment in use...
(so really there is no 'correct' siting or cable size- it all 'depends')

 

[Quattrohead]

You CANNOT use solid core copper wire (as used or AC wiring) for DC, Stranded copper is necessary and rated for the amperage it will handle.

I'm going to jump on the hassle Steve bandwagon and also ask why is this.

 

[SeaGal]

My initial answer is assuming that you're looking at PV array voltage as high as practically possible (e.g. 400V+).

I noticed the contradictory answers also.
Can tell you my inverters sit in a building 250 feet from array and 250 ft from the house..

LOL - so you've hedged your bets then! And talking of @Hedges I'm surprised at the different answers too, especially since we've covered this before in _that_ mammoth thread back in October - see posting here and rest of the thread is relevant.

Considering DIY Long distance from panels

I have a house that sits about 400-500 feet from an open 1 acre field. I live in area where (as far as I can tell) does not offer net metering services. I use approximately approximately 40kwh - 50kwh per day. The house is surrounded by trees and I would prefer not to add panels on the roof...

diysolarforum.com

I'm with @Hedges in better to transmit high voltage DC rather than low voltage AC if at all possible, for loss reasons and issues with voltage drop on 110V AC.

But, hey, this is the DIY Solar Forum - ask 10 "experts" and get 11 different answers!

 

[SeaGal]

I'm going to jump on the hassle Steve bandwagon and also ask why is this.

Yep. I can understand not having solid for high frequency AC due to the skin effect. Maybe all he meant is that if it is solid and thick enough it would be difficult to bend and terminate?

 

[Steve_S]

Never mind, I don't know anything about nothing.
Deadhorse subjects are pointless... Good Luck & Have all the fun you want...
Copper isn't cheap and won't be getting any cheaper "ever again", wire once or wire many times, entirely up to the person spending the cash.

 

[Partimewages]

Several manufacturers recommend fine stranded wire for terminations. Not all but some.

 

[Bop]

Never mind, I don't know anything about nothing.
Deadhorse subjects are pointless... Good Luck & Have all the fun you want...
Copper isn't cheap and won't be getting any cheaper "ever again", wire once or wire many times, entirely up to the person spending the cash.

IF there is a valid reason- then what is it???
Solid or stranded is fine under Au/NZ standards and is commonplace in many solar installations for the fixed cabling...
The Au/NZ electrical standards are amongst the highest in the world, and are accepted internationally (in the Eu and the UK, in fact ours are largely based on both)- unlike the US UL ratings (which have to be tested for acceptance by a recognised tester here- having a UL rating does not mean it will be accepted, unlike those having a EU or UK certification)

 

[Andrewr05]

Never mind, I don't know anything about nothing.
Deadhorse subjects are pointless... Good Luck & Have all the fun you want...
Copper isn't cheap and won't be getting any cheaper "ever again", wire once or wire many times, entirely up to the person spending the cash.

Huh? That's how you act when people ask you to back up the things you say? Weird.


I mean, you're correct about the stranded wire, but IT IS NOT a commonly known thing, why act flabbergasted when someone doesn't immediately bow down to your answer?

 

[timselectric]

Solid or stranded makes no difference, except for the termination points.
As for the original question. The longer distance should be done with the higher voltage. Whichever that is in each individual system.