Where is the best location for inverters

[wmeller]

I have a 5 kw system installed in my back yard about 150 feet from the meter. 36 panels, ground mounted, grid tied, 2 sunnyboy inverters.
I am moving them to the roof of the house. The center of the panel array will now be about 40 feet from the meter and i am wondering where the best place to put the inverters is.
should i have them up on the roof near the panels and run the power as AC to the meter OR should I run the power as DC from the panels to the inverters and place them in the basement near the meter ( about 40 feet away)?
My best guess is that with a large enough diameter wire it shouldnt make a lot of difference.
thanks

[Mike90250]

Inverters go in the coolest (most free air) place, as they reduce both lifetime and efficiency with heat. Most are slightly water-resistant, but direct rain and sprinklers from below, are bad. You may need an electrician to assist your moving the wires, making a mistake with high voltage DC and house current, usually ends poorly.

[wmeller]

that would be the basement

It is more than 20 degrees cooler in the basement and only 30 feet away. also dry. thank you for your help.

[Mike90250]

It is more than 20 degrees cooler in the basement and only 30 feet away. also dry. thank you for your help.

So you may have to up size your wires, to keep losses down. 30' distance is 60' of wire, and you have the DC and the AC to both consider.

[Jmac00]

wouldn't wire size be dependent on total amps??? If your less than 100 feet from the power source, your voltage losses should be minimal (less than 2%)

[Sunking]

wouldn't wire size be dependent on total amps???

Yes minimum wire size is based on the size of the breaker. This is a minimum safety requirement, but has nothing to do with design and voltage drop.

If your less than 100 feet from the power source, your voltage losses should be minimal (less than 2%)

I have not read all the details like what size wire is used and the load amps, but 2% voltage drop is a hard target to accomplish.

Allow me to explain. The voltage drop on a given wire is determined by the amount of current flowing, the distance of the wire, and the size of the wire.

For example a # 12 AWG copper wire maximum size breaker is 20 amps, and cannot carry more than 16 amps continuously. So lets say we have a 10 amp load current like a solar panel, with a 1-way distance of 100 feet. You will drop 2 volts. Well if this is a 12 volt system, a 2 volt drop is unacceptable as that is 16%. However on a 120 volt circuit is 1.6%.

[Jmac00]

Allow me to explain. The voltage drop on a given wire is determined by the amount of current flowing, the distance of the wire, and the size of the wire.

For example a # 12 AWG copper wire maximum size breaker is 20 amps, and cannot carry more than 16 amps continuously. So lets say we have a 10 amp load current like a solar panel, with a 1-way distance of 100 feet. You will drop 2 volts. Well if this is a 12 volt system, a 2 volt drop is unacceptable as that is 16%. However on a 120 volt circuit is 1.6%.

oops, my bad. when I think voltage,watts and amps my brain automatically thinks in terms of 110v

being new to solar, I have to start thinking in lower voltages when it comes to this stuff

[Peak Power Solutions]

If you are going to put the inverters in the basement, the city is going to want to inspect the area in which it will be going. Depending on what city you are from, regulations can differ from distances to walls, total area in the room, water outlets, electrical oultlets nearby, and yes conduit run. If it will be penetrating the roof surface, some cities will nail you and slap a big fine on you if system compliance isnt met per NEC.

Keep the inverters out of the sun, as mentioned. Inverter efficiency can drop more than 5% in some cases, but again, that is up to the homeowner. What is up to the inspectors is that it is away from any water source, usually 5 feet away from a pool or 3 feet away from a water outlet. Inside a garage is a good spot, but check the inverter specs for max efficency temprature.

[Mike90250]

being new to solar, I have to start thinking in lower voltages when it comes to this stuff

Not always, most grid tie systems use high voltage DC 350 - 550V in the solar loop, which keeps the amps down. The inverter is generally near the AV power panel, so all the power controlls are near each other.

[Jmac00]

sorry, i went on vacation for a week at the cabin

so an inverter should be in the coolest place? mine is in a closet next to a hot water heater . It's a 1500 watt, if I put it under the cabin ( the cabin in on pylons and it's about 4' off the ground) but the ground under the cabin can get "swampy" in the fall and spring.

would heavy moisture hurt an inverter?

what I really need to do is make a "battery house" and move the batteries, inverter and controller outside in a protected box.

[Mike90250]

Cooler is better, closer to batteries is best, dry is needed. under a house is not good. A seperate shed is better, so if something happens, it's not happening in your house.

[Jmac00]

what I'm thinking of doing is building a "battery House" on the outside of the cabin. I want to make it look like a very small shed. The batteries, inverter, charge controller and 40amp charger will go in there.

all I need is a 30" wide, by 24" deep by 30" high box and I can fit everything in it. I'm also going to get a couple of aluminum grounding blocks and used those as the positive and negative terminals. that way I will only have two wire going to the batteries, right now I have 4 wires going to each battery terminals and it's annoying the hell out of me , I have this thing for a clean/organized wiring scheme

[Mike90250]

I'm also going to get a couple of aluminum grounding blocks and used those as the positive and negative terminals.

Save everyone some time, pile the wood for the shed over the top of the batteries and controller and inverter, and light it now.

Aluminum should NEVER be used for terminal blocks. It oxidizes instantly, and is very tough to make a good connection to. (look up aluminun wire & house fires) Aluminun Oxide is used for sandpaper, it is so tough.

Copper or bronze, with thru bolts of Stainless Steel (copper is too soft for reliable threads) makes better blocks. Usually, comercial blocks are tin plated copper. (not solder tin, but plating)

[Jmac00]

Save everyone some time, pile the wood for the shed over the top of the batteries and controller and inverter, and light it now.

Aluminum should NEVER be used for terminal blocks. It oxidizes instantly, and is very tough to make a good connection to. (look up aluminun wire & house fires) Aluminun Oxide is used for sandpaper, it is so tough.

Copper or bronze, with thru bolts of Stainless Steel (copper is too soft for reliable threads) makes better blocks. Usually, comercial blocks are tin plated copper. (not solder tin, but plating)

okay, I'll find something else. I do know 3 or 4 electricians I can talk to to. I'm sure they will find something for me.