solar power back to meter

[jchealey]

I am having some solar panels installed and need to get the power back to the meter. I have a well junction box that is closer to the panels. Can I run the power to that juction box which goes back to the main panel?

It means a difference of 150 feet vs 300 ft.

thanks

Jerry

[HayZee518]

Will you be running DC to the box and then to the inverter before the main? What size wire is there now? What are you talking about for amps feeding into the inverter?

[jchealey]

The inverter will be at the panels. Running number 8 or 6 to the pump. Highest amprege will be 32 amps if every watt is producing. I was thinking of putting a 30 amp breaker going back to the panel. that will limit the amp flowing through the 10 gauge wire.

[HayZee518]

I plugged in some values into my voltage drop calculator and at a load of 32 amps at 120 volts I come up with a #1 wire. This is for a distance of 300 feet.
As you know, as voltage goes up, amps goes down by 1/2. Conversely as voltage goes down amps goes up!
Copper carries a resistance constant per foot which enters into the calculation.
What I'm envisioning is how you are going to run the complete circuit - #1 photocell, #2 conductors to the house, #3 Primary disconnect, #4 Voltage regulator/Charger circuit, #5 Secondary disconnect, #6 Batteries, #7 Inverter for 120 volts AC, #8 Disconnect for the AC, #9 Feed to transfer switch or breaker, #10 Panelbox connection.

[jchealey]

No batteries in the system, instead a meter that runs backwards. You lost me on the rest of the numbers. I am not sure what you are trying to point out. But, maybe the questions is: How do I feed the pump to still work and feed back to the meter at the same time? I don't know the answer to that.

[HayZee518]

No batteries in the system?? What happens when the sun goes down?? --> no power!!
Usually a wind generator or photo-voltaic array feeds batteries to store the energy. Also the photocell array's voltage is not constant - it keeps going up and down according to the sun's strength - or a passing cloud, henceforth your output will go up and down.
I don't think you can use the same line to feed the pump AND backfeed DC to the house. The AC to the pump, the wires will be a certain size as you said #6 or #8. #6 will carry 65 amps and #8 - 40 amps, but because it's DC,and considering distance the wire size will be BIG if you want the same current available from the source to the load. Take a look at the wire size in your car off the battery to the starter - must be around a #1 or 1/0 and this is for a short four foot distance!

[HayZee518]

[jchealey]

No batteries because, I will sell electric to the power company when the sun is out and buy it back when the sun goes down at the lower rate.

The inverter will be at the panels so the transmission will be AC. This hook up will be only for about 7 months while we remodel parts of the house. But I still want it to be safe.

[HayZee518]

Legally I don't think you can tap on after the meter and make it run backwards. Your input to the system has to be greater than what you're taking in for it to make any difference on paybacks.
Say your total house load is 48Kw. You'd need at least 48Kw to equal the house load and cancel out the power. 49Kw to feed power back into the system.
32 amps @ 12 volts = 384 watts, 32 amps @ 24 volts = 768 watts

32 amps @ 120 volts = 3840 watts

Check with your power company before undertaking this task.

[HayZee518]

Check this out:
http://www.sierrasolar.com/articles/sellpower.htm