East west array

petertearai
petertearai Solar Expert Posts: 471 ✭✭✭✭
in General Solar Power Topics #1
Do i need a charge controller on each array. Or can i parallel the east end west into one controller
2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,626 admin
    edited June 2021 #2
    If you have a PWM (pulse wave modulation) type solar charge controller--Yes you can without issue.
    If you have an MPPT (maximum power point tracking) solar charge controller... physically yes you can...
    HOWEVER, according to people that know a lot more about MPPT than I--You really need a separate MPPT charge controller for each "different" plane of panels--The father apart in temperature between the two arrays, the farther apart the Vmp-array voltages will be. And when you have two (or more) peaks in Vmp-array (cold panel higher Vmp, hot panel lower Vmp, and somewhere in the middle you may have another peak)--It depends on the specific programming of the MPPT software (three different peaks, which one will the controller "lock on to" is open to question)... And in any case, there is no "one peak" with two planes of panels that will be as efficient/peak harvest as if each array has its own MPPT charge controller.
    It sure would not hurt to try both planes into one charge controller--See if you can figure how much energy you may lose because of paralleling (i.e., 5 minutes on Array A, 5 minutes on Array B, and 5 minutes on A+B Arrays<?> at several different times of the day--Measure Vmp voltage for each setup).
    If Vmp-array from A to B is within 5-10% of each other (say VmpA=33 volts, and VmpB=30 volts), then you probably have ~5-10% loss (over 2x MPPT controllers) with just one MPPT controller (pure guess).
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,907 ✭✭✭✭✭✭
    #3
    Bill does have this right BTW. it is not just a guess on his part, but on the mppt's part and it's quality. Then, you throw in the biggest wildcard there is, and if you really need all of those watts, you are not going to be happy.

    Some mppt controllers even go into a search mode (they get confused) and harvest is interupted on both arrays.Not good with big loads running.

    The wild card is clouds and edge of cloud effects. Shade tolerant mppt controllers are the best at this in my opinion. It is also just easier to avoid it and use multiple mppts. The old way to avoid this was active solar tracking on a single array for the mppt.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • petertearai
    petertearai Solar Expert Posts: 471 ✭✭✭✭
    #4
    Thanks  for the info . Was hoping to add another fm80  and catch some early and late sun .
    I suppose i could just try, but a couple of cheaper mppt controllers might be the go . 
    Thanks again for your help .
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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  • 706jim
    706jim Solar Expert Posts: 521 ✭✭✭✭
    #5
    Your system is similar to mine. I have a southeast facing array (3 panels in parallel) and a southwest array (four panels in parallel) feeding an FM80. This system seems to work well for me without the need for a separate charge controller for each array.
    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.
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  • petertearai
    petertearai Solar Expert Posts: 471 ✭✭✭✭
    #6
    Thanks jim . Maybe i will try it .  At the moment its still an idea for the future .
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,907 ✭✭✭✭✭✭
    #7
    You should try it ! My comments are based on really large power systems where large loads need to run and be supported 100% of the time that the sun is out offgrid. You probably do not have that requirement. 
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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