Current limiter for battery charge

Discussion in 'General Electronics Chat' started by Remco, Nov 30, 2013.

  1. Remco

    Thread Starter New Member

    Nov 30, 2013
    I'm not an electrician, so excuse me if I might ask a maybe very simple question...

    The case is that I would like to limit the available ampere on a 230AC connection to 4, 6, 8 or 10 Amp without loosing Voltage and without disconnecting the current.

    This way, a device like a battery charger that normally uses 16 Amp can be refused to use this power and make an other fuse (limited to 8 Amp) disconnect the current.

    The solution should be able to fit into a small box like a cup of thee, and should not cost more the few dollars...

    Who can help me? What do I need?
  2. MaxHeadRoom


    Jul 18, 2013
    This was typically done in the past with a current transformer and a current meter with a settable trip.
    Not sure if the electronic versions are available now, but quite possibly?
    But it has to either have something that ignores inrush, or is employed after the fact.
  3. #12


    Nov 30, 2010
    Your question is a bit vague. Do you want to install an 8 amp fuse? Do you want to reduce the maximum current the battery charger delivers?

    Basically, you can't limit current without reducing the voltage unless you use some smart methods. You can't just tell a light bulb to be dim by putting a smaller fuse in series with it.
  4. t06afre

    AAC Fanatic!

    May 11, 2009
    Also what kind of battery are you going to charge. Most kind of cells are not so forgiving as the lead acid cell type.
  5. MaxHeadRoom


    Jul 18, 2013
    The idea I got from the OP was to disconnect power if the demand was over a set limit?
    I have done this with items such as furnace coal conveyors using the CT method.
  6. bountyhunter

    Well-Known Member

    Sep 7, 2009
    Power supplies do this by monitoring line current using a current transformer then having a relay that trips open and "times out" for a period of time then resets and keeps opening and timing out until the overload is gone.

    Impossible to do this for a few dollars.
  7. inwo

    Well-Known Member

    Nov 7, 2013
    The way this is handled in the real world is with keyed plugs. Like twist-locks. tm.

    Good battery chargers check for conditions (polarity and voltage) before enabling the load.

    Theoretically an AC supply could check the same way.

    Not simple, universal, or inexpensive.
    There would have to be a unique need to even consider it. IMHO
  8. inwo

    Well-Known Member

    Nov 7, 2013
    Furnas makes some really neat devices for this. Self contained and self powered.

    Used one to sense overload in a silo unloader. Time out reverse, time out reverse.

    The real reason I like them is that I've a bin full.:)

    Believe op's idea would require soft start or current limit.