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solar car battery charger

Discussion in 'Homework Help' started by Gizew, Jan 21, 2009.

  1. Gizew

    Thread Starter Member

    Nov 29, 2007
    hi every body! i need some direction.
    i thought to do a car battery charger that uses energy from the sun.
    the out put from the battery can be used for home use.
    i planned to use a regulator that controlls the power from the solar panel and after the battery inverter that inverts 12v to some voltage that is enough for home use.
    but i don'think that i know the limit interms of power that the inverter must have. and the overall ckt of the inverter and the regulator of the battery.
    please those who have ample of idea on this let i have some way from you!
  2. HarveyH42

    Active Member

    Jul 22, 2007
    Car batteries were not intended for anything more than starting the car. You'll want a deep-cycle, marine type battery for this. I'd suggest buying off-the-shelf, rather than building your own. Batteries and solar panels are kind of expensive, charge controllers and inverters have come down in price considerably, and pretty involved to build. Doubt you can do it cheaper or better, money you save could go to a larger panel.

    You should figure out what you plan on running first, then try and figure out how much power you'll need. Better to find 12v devices, instead of the inverter, less wasted power.
  3. italo

    New Member

    Nov 20, 2005
    A deep cycle imply a deep discharge cycle whereby the battery can still be usefull after. It has nothing to do with his problem. Firt of all a 12v car battery is never 12v more like 13.68v . A solar panel can and will charge this battery provided that the solar can replenish the battery power loss. putting a small panel will never do it a 15 watt panel will charge it again provided that the voltage and current exceed the drain. An car battery will die after a month or so just by sitting there as we all know. Now a 15w cannot realy doa good job if the drain was excessive well maybe afte a long time. your problem is to balance drainn Vs chrge
  4. Audioguru


    Dec 20, 2007
    Your English and spelling are horrible.
  5. thingmaker3

    Retired Moderator

    May 16, 2005
    I concur with Harvey: Begin the project by determining power needed by the load. Will this run a few lights? An irrigation pump? A transceiver?

    Once power needs are known, the inverter, battery bank & charger, and solar cells can be sized to accommodate.

    Even if deep cycle batteries are used (and they should be used) one would be wise to size the battery bank and solar cell bank large enough to keep them from discharging below about 90% of their full charge voltage. (This will let them last about five times as long as discharging them to 50%.)