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rearrange batteries with relays?

Discussion in 'Electronic Basics' started by BobG, Dec 13, 2005.

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  1. BobG

    BobG Guest

    Surely there must be a name for this subject.... an array of contactors
    in a row and column arrangement of 12 batteries to allow series and
    parallel connection as 12,24,36,48,72,96,and 144 volts etc? You cant
    always use the bottom battery in the stack to run on slow... the
    submariners must have worked all this out in the 40s....
  2. Dan Hollands

    Dan Hollands Guest

    What's the question?

    Dan Hollands
    1120 S Creek Dr
    Webster NY 14580
  3. BobG

    BobG Guest

    If its been done before and is a mature technique, I just need some
    keyword to look for it. If its a clever new idea of keeping batteries
    leveled by parallelling at lower voltages, I'd like to brainstorm on
    how to do it with mosfets or something more efficient than contactors.
    Do they make latching contactors that go to zero watts after latching?
  4. Dan Hollands

    Dan Hollands Guest

    I've never seen an application for this type of device

    Dan Hollands
    1120 S Creek Dr
    Webster NY 14580

  5. Pooh Bear

    Pooh Bear Guest

    It looks like speed was controlled by the configuration of the motor

    " The motor bus can be split for operation of the motors on each side
    independently of the other sides (BUS TIE OPEN), closed for parallel
    operation of both motor groups (BUS TIE CLOSED), connected to the battery
    bus for battery operating of the main motors (BATTERY BUS), and lastly, for
    series operation of all motors the positive side of one motor bus can be
    cross-connected to the negative side of the other motor bus, so that by
    proper closing of the motor contactors, all four motors can be placed in
    series for slow-speed operation on the battery bus (SLOW).

    Either or both batteries are connected to the battery bus by closing their
    respective contactors which, in turn, are controlled by one operating
    lever. "

  6. cbm5

    cbm5 Guest

    They used four motors or a couple split-armature motors, and varied the
    speed (actually, torque) by connecting the armature windings in
    different combinations of series and parallel, and also by varying the
    shunt fields for fine control. There are quite a few combinations
    available, especially when a submerged submarine barely needs more than
    "fast" and "slow".

    These days most electric motors will use pulse-width modulation or
    variable-frequency multiphase drives. Certainly much less complicated
    than switching banks of batteries around, and you can use feedback to
    make adjustments for dropping battery voltage.
  7. BobG

    BobG Guest

    OK, thanks for the info on how they did it in submarines. Back to the
    present. 12 batteries seems like a nice number because it has lots of
    divisors. You can get 12V with all 12 in parallel, 24V with 6 banks of
    2 in series, 36V with 4 banks of 3 in series, 48V with 3 banks of 4 in
    series, 72V with 2 banks of 6 in series, and 144V with all 12 in
    series. Is 6 speeds enough for an electric car? (probably not), but I
    get the idea that when using regen, the computer thinks... hmmm slowing
    down from 30mph... motor putting out 26V.... reconfigure battery bank
    to 24V... slap motor on battery bank. Or however programmers make
    computers reason these things out.
  8. kell

    kell Guest

    The question of how many switches you need and how many poles and
    throws per switch would be a math problem. You could offer it up to a
    high school teacher or a professor at a local college as something for
    his students to work on, although an engineering professor might tell
    you it isn't practical to use batteries that way.
  9. Jasen Betts

    Jasen Betts Guest

    AIUI they use a buck/boost voltage converter these days.
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