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Battery questions...

Discussion in 'Electronic Repair' started by gothika, Feb 11, 2004.

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  1. gothika

    gothika Guest

    I've got a couple of miniDV camcorders that I'm wanting to build
    external battery packs for.
    One uses 7.2 volt Nimh rechargables and the other uses 7.4 volt
    Lithium Ion.

    I can get Nicad modules rated at 1.2 volts at a really cheap price.
    I can wire 6 in series to get the 7.2 for the one.
    However the second needs 7.4. I either wire 6 for a 7.2 rating or 7
    for 8.4. Would the 8.4 be bad for tthe camera?
    Or are their modular rechargables that I can purchase to get the 7.4?
    also the modules I'll use are "sub" C's and are rated at 1200mh.
    Can I use two series modules in tandem to get 2.4AH safely?
    The cameras in question are a Canon Optura and a Canon ZR45mc.
    I suppose if someone here is willing to give me battery 101 inregards
    to the newer generation of rechargables I'd be deeply indebted.
    Also I have several sizes of sealed dry lead acid rechargables that I
    can step down or up. Is it safe to use these in place of Nimh or
    Lithions?
     
  2. Jerry G.

    Jerry G. Guest

    You should be able to use 6 of the standard 1.2 Volt NiCad or Lithium cells.
    From 7.2 to 7.4 Volts there is not much practical difference. Infact with
    these cells are fully charged they are close to about 8 volts. When
    discharged they will go down to about roughly 6.5 to about 6.8 Volts before
    the weak battery indicator will show. This is for most of this category of
    unit.

    --

    Greetings,

    Jerry Greenberg GLG Technologies GLG
    =========================================
    WebPage http://www.zoom-one.com
    Electronics http://www.zoom-one.com/electron.htm
    =========================================


    I've got a couple of miniDV camcorders that I'm wanting to build
    external battery packs for.
    One uses 7.2 volt Nimh rechargables and the other uses 7.4 volt
    Lithium Ion.

    I can get Nicad modules rated at 1.2 volts at a really cheap price.
    I can wire 6 in series to get the 7.2 for the one.
    However the second needs 7.4. I either wire 6 for a 7.2 rating or 7
    for 8.4. Would the 8.4 be bad for tthe camera?
    Or are their modular rechargables that I can purchase to get the 7.4?
    also the modules I'll use are "sub" C's and are rated at 1200mh.
    Can I use two series modules in tandem to get 2.4AH safely?
    The cameras in question are a Canon Optura and a Canon ZR45mc.
    I suppose if someone here is willing to give me battery 101 inregards
    to the newer generation of rechargables I'd be deeply indebted.
    Also I have several sizes of sealed dry lead acid rechargables that I
    can step down or up. Is it safe to use these in place of Nimh or
    Lithions?
     
  3. gothika

    gothika Guest

    Thanks for the info. I've gotten a bit paranoid with much of the
    modern miniature electronics is soo easy to pop the diode or whatever
    they use to protect power in.(If they do that much.)
    I dug out the AC adapter/ recharger for the zr45 and noticed the
    output on it was kinda high,9.5vdc at 2.7amps.
    Is there a safe limit on the AH of the battery used?(I've seen some
    try and use large batteries with disastrous results.)
    I'm thinking that a battery with a higher AH rating than the largest
    oem rated battery might stress the caps.(correct me if I'm off field.)
    I have a variety of 6 volt lead acid rechargables from 3.2ah up to
    about 9.
    It'd be nice to have a belt pack that could run the camera for several
    hours.(I've done this with broadcast equipment but they're a lot
    tougher, heck I've used car batteries on pull around dollies for my
    old 3 tube/chip stuff.)
    Thanks again, Jerry.
    Harry
     
  4. Bob Kos

    Bob Kos Guest

    I don't think the voltages are much of an issue. I think what you have to
    be more careful of is the charging of the LIon pack. I'm by no means an
    expert, but it is my understanding that charging these cells involves a
    little more than hooking up a wallwart to the correct terminals. It's also
    my understanding that these cells become quite unstable if handled
    incorrectly. Laptop computers have taken charging / discharging LIon cells
    to a scientific level for a reason. After a certain point, they'll quit
    charging a battery module if individual cells are not charging properly.
    You need to have a good understanding of the technology you are going to
    employ in your new packs.

    Good luck with it.
     
  5. gothika

    gothika Guest

    Thanks for the input. I'm using plain old Nicads though.
    I prefer lead acid or nicads for their simplicity and reliability.
    I have alot of the Lion packs but find they tend to work erratically
    under temperature extremes.(I do alot of shooting in cold/hot
    weather.)
    I've had brand new Lion packs that charged and worked perfectly well
    in studio, but when taken out in the field would register as low or
    even dead.
    The packs I built for these cams are working very well.(sub-c nicads,
    1.2 volt modules in series of 7.)
    I do a lot of location work, Mardi Gras being one of my bigger jobs of
    the year. As a result I hire several cameramen to cover this event.
    Most are experienced videographers some just knowledgeable
    photographers.
    I supply the gear and they do the labor.
    This usually works out ok, at least up to this year.
    I'd hired a new guy who managed to burn out the Optura.
    When he'd used up all the battery packs I'd built for the Optura he
    tried hooking up a pack of his own. Of course the polarity was
    wrong.(It was a 12v pack for smaller broadcast cameras.)
    I had my van centrally located with a portable charging station so all
    my shooters had to do was come by and swap out packs.
    This genius got lazy tho' and decided to use a pack that he used in
    his regular day job at his local tv station.
    I won't be using him next year for sure.
    For anyone here looking to build camera batteries on the cheap here's
    a very inexpensive solution.
    Harbor freight and tools sells their line of cordless rechargable
    drills in both 9.6 volts and 12v models.
    The 9.6 volt battery packs go for 3.99 and are perfect for most small
    cameras.
    I had several of the 9.6v drills in my set shop and thought why not
    give the batteries a try for my cameras. They worked very well.
    You can open up the battery case and bypass a cell or two for smaller
    voltage applications and with a power cable and the adapter plug for
    whatever camera you have you've got plenty of low cost battery packs.
    The 9.6v are rated at 1300mah about an hour for most small cameras.
    The Harbor Freight 9.6 drill has a retail price of around 12.95 and
    can be hand on sale for 9.95. It includes a charger and 1 battery
    pack.
    The charger is a wall wart that connects to a clip on charge regulator
    via a dc coaxial plug.
    I took one of the charge regulator modules and rewired it to bypass
    the circuitry. It makes swapping out batteries easy.
    I use a cable with a power coax on one end and the connector for the
    camera on the other.
    3.99 for an hour of camera use vs 29.95 for oem batteries is a pretty
    good deal.
     
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