12 Vdc lighting off of 48Vdc battery bank question

Hi im new to forums and not sure if in in the right convo but here goes. I have a question in regards to DC cable. Type of cable and size to run 5x 48v DC LED off a solar battery pack? and are 48v DC motion sensors available ?

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: 12 Vdc lighting off of 48Vdc battery bank question

    Welcome to the forum Stefan,

    I have moved your question to its own thread--You can lead the discussion as you need.

    With any electrical question, we need to know the power (power=Voltage*Current), the length of wire/cable (longer cable, more voltage drop, larger copper wire needed) and any special requirements (flexible cable, indoor/outdoor, salt water, portable use, etc.).

    In and of itself, there is nothing special about 48 VDC. The only concern is that 48 VDC is realitively high voltage (vs 12 VDC), and many switches/breakers/fuses that you would find for cars/trucks/boats are not rated to safely be used at 48 volts.

    And standard 120/240 VAC breakers are not usually rated for 48 VDC (batteries will go as high as 60 VDC during charging) either.

    Regarding a 48 volt motion detector, if you would like to build your own, you can find kits:

    http://www.jameco.com/webapp/wcs/stores/servlet/StoreCatalogDrillDownView?langId=-1&storeId=10001&catalogId=10001&categoryName=cat_35&subCategoryName=Sensors&category=3525

    And you may need to build/buy a 48VDC to 5VDC down converter, etc...

    But, back to the basics, you also have to size the battery bank and solar array to the amount of light you will need (i.e., 5watts * 1 hour per night, vs 15 watts * 10 hours per night, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: 12 Vdc lighting off of 48Vdc battery bank question
    stefan wrote: »
    Hi im new to forums and not sure if in in the right convo but here goes. I have a question in regards to DC cable. Type of cable and size to run 5x 48v DC LED off a solar battery pack? and are 48v DC motion sensors available ?

    As Bill mentioned, 48 volt system are high voltage and require more expensive switches, fuses, breakers, wiring, etc. Have you considered DC-DC converters? The converters have a cost, but so does the 48 volt wiring. The 12 volts that a DC-DC converter makes is unvarying, unlike a battery voltage that changes with the charge/discharge cycle.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i