12v solar to 24v batteries

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joel
joel Registered Users Posts: 4 ✭
in General Solar Power Topics #1
I have 2 x 100w solar panels, 2 x 12v 100ah batteries and a 12/24v 30amp controller(EPEVER model Es3024a) can I make this into a 24v system?
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #2
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    yes, likely.

    You would put the batteries in series for 24 volts. and use 12 volt nominal panels in series for a 24 volt nominal array...
    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: 2,044 ✭✭✭✭✭
    #3
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    Needed to check model number. Is this a VS 3024A? if it is then yes you can do 24 volts. Epever has mppt controllers in their lineup and if it were an mppt controller then the answer would be you would need at least one more panel to raise the input voltage high enough above the battery  voltage for the mppt to do it's thing.

    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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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #4
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    What are the exact specs on those panels? If Vmp is > 17V they will work fine if in series.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • joel
    joel Registered Users Posts: 4 ✭
    #5
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    Yes littleharbor VS3024A how do I connect solar panels in series?

     2- Solar Panel 100W Polycrystalline 12VDC 1- PWM 30A Solar charge controller with LCD screen to regulate voltage between the solar panel and the battery(s).-Model: WP3024Z -System voltage: 12V/24V Auto -Dimension: 187mm x 98.5mm x 49.5mm -Weight : 400g Solar Input: -System voltage: 800W (12V) / 2000W (24V) -Solar input voltage: <50V -Rated input current: 30A Battery: -Battery type: Sealed, GEL, Flooded and User -Charging mode: 4 Stage (Bulk, Absorption, Float, Equalizing), PWM-Float voltage: 13.7V (13V~15V) x1/x2/x4-Absorption voltage: 14.4V (13V~15V) x1/x2/ 2- 12 AWG Solar cables to connect the solar panel to the charge controller, each of 20Ft long with MC4 Connectors 2- 12 AWG Solar cables to connect the controller to the batteries. Each cable is 7Ft long and comes along with alligator clamps for easier setup between the charge controller and the batteries. Type: SEDC-100W 1) Cell Type: Polycrystaline (A Class) 2) Voltage: 12 VDC 3) Dimension: 50*28*1 in 4) Rated power (Pmax): 100W (+/- 3%) 5) Open Circuit Voltage (Voc): 22.54V 6) Short Circuit Current (Isc): 5.64A 7) Max Power Voltage (Vmp): 18.72V 8) Max Power Current (Imp): 5.35A 9) Solar Panel Grade: A 10) Nominal Operating Cett Temperature: -40 to +85C 11) Maximum System Voltage: 750VDC 12)

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #6
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    Here is a nice explanation of series/parallel:

    http://hespv.ca/blog/wire-solar-panels-parallel-vs-series/

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,044 ✭✭✭✭✭
    #7
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    Out to controller+       -+   - out to controller.

    Assuming you have polarized connecters on your panels you will plug the positive lead from panel #1 into the Negative lead from panel #2. Now you have a positive and negative lead hanging free. these connect to your charge controller. 

    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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  • joel
    joel Registered Users Posts: 4 ✭
    #8
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    Cool guys, thank you so much, it's all connected and working fine.
    Now I have another Question: what would be the less drain on batteries? 12v 24v or install a converter and run 110w? I'm running a Whynter 62QT dual zone fridge/freezer.
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #9
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    12v may be a bit more efficient (assuming short cable), but if you're set up for 24v I would use that. Inverting to 120v should be less efficient than either dc voltage.
    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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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #10
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    Also, I hope you have a generator or other means of charging batteries for low sun days. The fridge will drain those batteries pretty quickly and you don't want to drain them to much less than 50% full.
    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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  • joel
    joel Registered Users Posts: 4 ✭
    #11
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    It's been pretty good so far on 12v the solar panels have been keeping up, on cloudy days I turn the frige off occasionally, but I read that it would be less of a power drain on the batteries at start up on 24v so I'm trying that, it's using 2amp while running. I was thinking of installing a timer to minimize usage, I don't think it needs to run as much as it does. 
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