Reducing Battery BAnk Voltage

What's the simplest, most efficient way to reduce voltage on a 48 volt battery bank?
My coolers run on 12v and my water pump runs on 24v. The simplest and most efficient way may not be the best?

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,432 admin
    Re: Reducing Battery BAnk Voltage

    Generally, some sort of DC to DC converter:

    Electronic Transformer style (24 to 12, or 12 to 24)
    Traditional DC to DC Converter/Power Supply

    You could possibly even use a solar charge controller (use 48 volt on PV input to "charge" a 12 or 24 volt battery bank (I await somebody who knows better than I if a MPPT type controller is appropriate for this type of application).

    Pretty much never "tap" another (lower) voltage from a battery bank--will unbalance the charge between cells and lead to early failure.

    -Bill

    PS: Add the old convert the unit to 120 VAC and use an inverter.

    PPS: Wind-Sun does not list these others... But there are other voltage/current "Electronic DC Transformers" available too from the above company (and other products)...
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Reducing Battery BAnk Voltage

    I had to do this to for a 12VDC lighting project, and used a dozen 48v - 12VDC-DC converters. The PV array charged a large 48V battery bank, which then powered all the 12V converters. Same could be made for 24V loads. The converters were about 93% efficient, 12V 10A output.
    raw converter
    http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=454-1190-ND
    Construction:
    http://www.naturalstudies.org/Photo_galleries/LED_driver/
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Malasombra
    Malasombra Solar Expert Posts: 24
    Re: Reducing Battery BAnk Voltage

    You can add 12v elements in series to reach those 48v, at least is a possibility for your coolers.