additional pv panels

royz
royz Registered Users Posts: 1 ✭
in General Solar Power Topics #1

I have one of NAWS rv kits 3 years old with 2 x325 kyrocera panels a Morningstar 60 CC and 4 crown 220 amp/hr batteries

my question is would the batteries and CC cope with an additional 200/250 watt  panel my batteries are in good condition but I would like to have a little more storage capacity

Thanks

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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #2
    IMO, adding another panel might be pushing it for the controller (assuming 12v bank, would be ok at 24v).  You'd also want to check panel specs to see how it would fit in.  

    Adding batteries to a 3yr old bank probably isn't a great idea either.  5yrs is a good age for a GC type battery, and adding would likely age out the new along with the old.  Probably better to work the existing ones harder for whatever life they have left, and plan for expansion when they croak.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    edited November 2018 #3
    I agree with @Estragon. I would not add batteries to a battery bank that old.

    Personally off grid systems are rarely max out the charge controllers capacity if you are using the top 30% of the battery bank. I'd think adding up to 325 watt panel would be fine. At first glance it would look like 975 watt array would be way out of line for a 60 amp charge controller. But in general you will get a max of about 750 watts off the array when the sun is within 15-20 degrees of perpendicular angle to the array. Consider your charging voltage by the time this would happen would be near or at absorb for your bank or around 14.5 volts so 750 watts ÷ 14.5v = <52 amps. In reality, you will likely never max out the charge controller unless you angle your panels to catch the morning sun and run them very far down at night.

    I would see if the extra energy to keep things running during the evening hours and morning from the array, helps you use less energy from the battery bank. You might also practice some load shifting, doing what you can when the batteries have reach float and you have the extra energy coming from the sun that could be put to use! Perhaps you can extend the life of the battery bank to 4-5 years before replacing it.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,102 ✭✭✭✭✭
    #4
    Your 325 watt panels are likely 72 cell panels. Adding some 60 cell 250 watt panels to your array isn't a good idea. If you can find some 190 watt 72 cell panels they would match up , voltage wise, better with your 325 watt panels.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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