Which option of three to choose 12V vs 24

Daliokas
Daliokas Registered Users Posts: 2
Hello 

Introduction. Your advice is needed. Planing to install off-grid PV system on my vacations house (to connect to the grid is quite expensive option).
I have three PV panels that technical data is:
 Pmax - 250W, 
Umpp - 30.79V
Impp -8.12A
Uoc - 37.29V
Isc-8.69A

And there three option to go with istalation.

1) 3 panels consistently + Victron BlueSolar MPPT 150/45-Tr + 12V accumulator
2) 3 panels consistently + Victron BlueSolar MPPT 150/35 + 24V accumulator (2x12V accu)
3) 3 panels in parallel + STECA SOLARIX PRS 3030 + 24V accumulator (2x12V accu)

The lowest price delivers 3) option but not sure will it work in a right way. 

Thanks a lot

Comments

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

    Don't buy anything until the entire system is planned on paper.   I would not assume that any of those controllers is the right one for you.

    First step is to determine how much electrical energy you need.  Second step is to choose a system voltage and battery that can meet those needs.  Then the third step is to choose the panels and controller that are able to recharge the battery that was chosen in step 2.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Daliokas
    Daliokas Registered Users Posts: 2
    edited June 2016 #3
    Hi, 
    Panels already bought :) 
    now have to choose right controller and batteries. Electricity needs not big. LED lightning insout/outside, 2 security cameras with control unit and motion sensors with GSM link, maybe smal LCD TV set, and small fridge.

    DJ
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Daliokas said:
    Electricity needs not big. LED lightning inside/outside, 2 security cameras with control unit and motion sensors with GSM link, maybe small LCD TV set, and small fridge.
    Your electricity needs may not be big, but they are not small either. 

    We have all sorts of formulas to calculate all aspects of an off grid system.  But these formulas use numbers!  One of the most important numbers is daily energy use (kilowatthours). 

    Suppose you were buying a truck to pull a trailer... in order to choose the correct truck you would need more detail than "the trailer is not too heavy".  You would need the actual weight of the trailer.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i