Adding 4 panels facing east?

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softdown
softdown Solar Expert Posts: 3,824 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
About 25 degrees. Help in the summer with fridges and freezers!
Almost 800 watts. p
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
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  • softdown
    softdown Solar Expert Posts: 3,824 ✭✭✭✭
    #2
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    I'm at latitude 37 degrees
    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
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  • softdown
    softdown Solar Expert Posts: 3,824 ✭✭✭✭
    #3
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    Good idea? Much help?
    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
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,457 admin
    #4
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    A quick calculation using PV Watts (using my defaults for off grid AC power)...

    https://pvwatts.nrel.gov/pvwatts.php

    Fort Morgan Colorado, 1 kWatt fixed array facing East, 40 degree tilt from horizontal, 52% efficiency or 48% losses in program:



    Same thing, but 180 degrees or facing south:



    What is it worth to you (play with panel angle for East array, possibly favoring December/winter production)?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • softdown
    softdown Solar Expert Posts: 3,824 ✭✭✭✭
    edited March 22 #5
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    https://pvwatts.nrel.gov/pvwatts.php  This likely takes you to your internet source. Golden, CO with this VPN. My calculations are for Alamosa, CO at 37.3 latitude. 

    Got 1530 kWh with a 22 degree panel orientation. Within ~ 15% of the standard 180 degree southerly orientation - which yields 1785 kWh. I am liking the ability to start ramming the batteries with useful energy shortly after the sun rises. Have plenty of panels facing south.

    Perhaps I am missing something however? 
    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
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  • Desert Rat
    Desert Rat Solar Expert Posts: 138 ✭✭✭
    edited March 22 #6
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    softdown said:
    Good idea? Much help?
    Yes and yes. I have three separate arrays, two @ 1600W and one @ 1560W. The two 1600W arrays are facing due south, and the 1560 is split into two strings, with 780W facing east and 780W facing west.
    Each array is on its own charge controller, so I can easily compare output. This morning the 1560W array had greater watt-hour output than either of the two other arrays, up until the system reached absorption.
    That's with half of the array facing directly away from the sun! Yes, south facing panels would theoretically have more output during the day, but once you've reached absorption it's a moot point for off grid. Of course the east/west array doesn't help as much during the period two months either side of the winter solstice, but it's a big plus for summer A/C and refrigeration loads. 

    I'm at 29⁰. The south facing arrays are at 15⁰, and the east/west panels are at 30⁰.
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  • softdown
    softdown Solar Expert Posts: 3,824 ✭✭✭✭
    edited March 22 #7
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    Foggy memories dictate that a separate charge controller is needed. My ‘math’ dictates that a 20 amp controller should suffice. MPPT being significantly better than PWM. 


    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
    · Share on Twitter

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