12v solar pv charging 24v battery bank and vice-versa

renaultscenic2renaultscenic2 Registered Users Posts: 16 ✭✭
I just want to know if a 12 volt solar pv connection can charge a 24v battery bank and also a 24v charging 12v battery bank

Comments

  • DConlyGuyDConlyGuy Registered Users Posts: 80 ✭✭
    and mppt controller can use high voltage to charge a 12 volt battery easy enough, the other way 12volt to 24volt can be done but not really worth it
    600 watts of solar panels,Epever 30 mppt , 2 PWHR12500W4FR battery's in 24 volt setup
  • renaultscenic2renaultscenic2 Registered Users Posts: 16 ✭✭
    Ok thanks for the info
  • BB.BB. Super Moderators, Administrators Posts: 31,911 admin
    There are ways to do it as DC says, but it is usually not cost effective in most cases.

    Do you have a specific application?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • vtmapsvtmaps Solar Expert Posts: 3,739 ✭✭✭✭
    Genasun makes some boost controllers that can charge a battery with a lower voltage solar panel. 

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • renaultscenic2renaultscenic2 Registered Users Posts: 16 ✭✭
    The issue is I have 2 200watts panel connected in parallel,and I want to use a 24v inverter and I dont want to go on the roof to make a serial connection on the panels thats why im asking.
  • BB.BB. Super Moderators, Administrators Posts: 31,911 admin
    There are chargers/DC to DC converters that let you take energy from the "low 12 volt" string and use it to both charge and discharge the "high 12 volt" string of batteries. This is not "unusual" for use in buses and trucks (24 volt chassis, 12 volt "house power").

    But these devices are not cheap (several hundred dollars or more?). Here is a smaller version that is capable of "balancing high and low 12 volt strings" and a "bus" balancer/equalizer:

    12/24 Volt DC/DC 20 Amp DC-DC Converter ($230 from our host)
    http://www.vanner.com/manuals/EQUALIZER-80CAN-SERIES.pdf

    The Genasun controllers may work for your needs for ~$120 to $190)--Not sure (details matter--some more reading required):

    http://genasun.com/products-store/mppt-solar-charge-controllers/mppt-for-lead-acid/

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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