An argument for west and east arrays vs the traditional south array.

softdown
softdown Solar Expert Posts: 3,985 ✭✭✭✭
Battery wear and tear is the chief long term expense of off grid solar
South facing solar production is strong from ~ 9am to 3pm. 
East and west array production is substantial from ~ 7:30am to 5pm. This should, in theory, potentially lower battery wear and tear. 

Additional arguments for the west and east arrays:
1) A small amount of work may allow one rack to hold both the west and east arrays. Though two charge controllers will be needed. I hope to post a pic of using one rack for both arrays when it is done. 
2) The longer hours may help reduce the impact of summer time air conditioning. Summer time is when the west and east arrays compete more evenly with the south arrays. 
3) The east array protects the west array from easterly wind shear. The west array protects the east array in the same way.
4) Some applications will find the west/east more favorable for reducing shade. Others will still favor the south array. 
5) If you tend to have cloudy mornings or afternoons the installer may adjust west vs east production accordingly. 

* I don’t remember the name of the web site that allows the more exact numbers to be crunched. But I do remember that west and east arrays can be competitive except for substantially more limited production during the winter months. 

I’m not saying that west and east panels offer more production. They absolutely do not. But a longer and more evenly balanced production? It should.
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,702 admin
    edited August 13 #2
    Can supply more information, including hour by hour 24x365 for spreadsheet. 
    Might look at Southeast and Southwest facing arrays with pvwatts.
    Lithium batteries work fine on se/sw arrays as well as South facing. can be fully charged in several hours (check manuals and specifications).
    For lead acid, need 10+hours on charge to fully recharge (bulk+absorb+reach float) especially important during short winter days. 
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • 706jim
    706jim Solar Expert Posts: 524 ✭✭✭✭
    I have one array facing southeast and a second facing southwest. All panels in parallel and a single FM80 charge controller. The system works great as built.
    Island cottage solar system with appriximately 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing due south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter which has performed flawlessly since 1994. Outback Flexmax 80 MPPT charge controller four 467A-h AGM batteries. Insignia 11.5 cubic foot electric fridge 1/4hp GSW piston pump. My 31st year.
  • Miller_Ranch
    Miller_Ranch Registered Users Posts: 46 ✭✭
    edited 1:00PM #4
    I would suggest the Wattsun HZLA for East and West production.

    https://www.wattsun.com/images/datasheets/AccuTrak_HZLA.pdf