Less power loss AC/DC

art_swenson Registered Users Posts: 1

I have an outdoor wood boiler here in the great north woods of New Hampshire that I want to take off the grid.

The stove is 100 feet from the house and draws current for two water pumps, stove blower and light. I have all the

equipment off my sailboat that’s in dry dock for the winter. ( two solar panels, controller, inverter and deep cycle batteries.


It’s to shaded at the wood shed for the panels so they’ll be 100 feet away in the open, is it more efficient to run DC from the panels to the wood shed where the controller and inverter and battery will be located or is it better to convert the DC to AC as close to the panels as possible and run the AC the 100 feet to the wood shed for the equipment.

Thanks for your help





  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Welcome to the forum,

    What matters is voltage, not AC or DC.   The higher the voltage, the thinner the 100 ft long wire can be.

    My solar panels are 120 ft from my controller.  I have the 30 volt Vmp panels configured with a string length of two.... therefore I am transmitting the power at 60 volts.   If I had put the battery & electronics out with the panels, I could have transmitted 120 volts AC back to the house and saved a small amount of money on the wire.

    Lots of folks transmit higher voltage DC... just put more panels in series to raise the voltage.  Of course, your charge controller has voltage limits... make sure you don't exceed them.   and on that subject...  If you put more panels in series, use the series Vmp in a voltage drop calculator for sizing the wire, but use 125% of the Voc for calculating maximum string voltage to the controller. 

    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • zoneblue
    zoneblue Solar Expert Posts: 1,220 ✭✭✭✭
    Agreed, 100ft isnt a major probem. Mine is about similar to Vts about 60feet at 70V.
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,

  • BB.
    BB. Super Moderators, Administrators Posts: 33,493 admin
    Do you know how much power your pump, fan, and lights will use?

    What is the "native" power for the equipment (AC/DC and what voltage)?

    In general, solar power is expensive--If you have AC Utility power, it is probably cheaper and more reliable--Especially in New Hampshire during the winter (backup power with genset during bad weather?).

    A smaller solar power system can work--But if your loads are fairly large (a few 100 watts of motors running 12+ hours per day), the system gets expensive quickly.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset