How to use variable AC/DC power supply

Discussion in 'Electronic Repair' started by CharlesBlackstone, May 17, 2008.

  1. Hi, I bought a variable voltage variable amp power supply to use
    charging my RC batteries:
    http://shop.vendio.com/evan2002/item/857080628/index.html

    I don't really understand it much though. First, should I never turn
    it on if there is no load?

    I will use it with either a nicd/nimh charger or a lipoly charger. In
    either case, should I turn the voltage to 12 volts, and the amps to
    the maximum (10), then turn on the charger? Should the charger be
    hooked up and turned on with a battery connected to be charged, before
    I turn on the power supply?

    Thanks very much in advance for any guidance.

    Jim
     
    CharlesBlackstone, May 17, 2008
    #1
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  2. Thanks for the replies.

    I bought this power supply for $300, because I have other uses for it,
    such as in my laboratory at work. But in some applications, I will use
    it to its max to charger very large battery packs for very large
    planes. It is what other people who do what I do buy.

    RC battery chargers do not come with power supplies.

    This is the charger:

    http://www.batteryjunction.com/temilibachwl.html

    Thanks for any helpful replies.
     
    CharlesBlackstone, May 17, 2008
    #2
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  3. CharlesBlackstone

    bz Guest

    CharlesBlackstone <> wrote in news:17fdbbc6-
    :

    > Thanks for the replies.
    >
    > I bought this power supply for $300, because I have other uses for it,
    > such as in my laboratory at work. But in some applications, I will use
    > it to its max to charger very large battery packs for very large
    > planes. It is what other people who do what I do buy.
    >
    > RC battery chargers do not come with power supplies.
    >
    > This is the charger:
    >
    > http://www.batteryjunction.com/temilibachwl.html
    >
    > Thanks for any helpful replies.
    >
    >


    Your supply seems to have two kinds of limits.
    Voltage and current.

    This means that you can regulate the 'open circuit voltage'. You would want
    to make sure that never exceeds your battery voltage by more than a few
    percent.

    The current regulation means you can regulate the 'short circuit current'.
    You would want to make sure this never exceeds the safe charging current
    for your battery (which should be something on the order of 10% of the
    discharge current).

    You should look up the charging conditions for your particular battery,
    with nothing connected to the supply, set the open circuit voltage.
    Then, with an amp meter (perhaps the supply has one built in), short the
    output and set the current to less than the max charging current.

    NOW, you can connect your battery to be charged.

    Since you have a 'dumb charger', you will need to monitor the charging to
    make sure you don't overcharge the battery.
    If your voltage and current settings are correct, that shouldn't happen,
    but .... it is better to be safe than sorry.

    What you do NOT want to do with a TRUE current supply (one that could go to
    any voltage) would be to open circuit it, because it would go to infinite
    voltage.
    What you do NOT want to do with a TRUE voltage supply (one that could go to
    any current) would be to short the output because the current would be
    infinite.
    A supply that regulates BOTH, however, is limited in both and thus kind of
    the best of both worlds.




    --
    bz 73 de N5BZ k

    please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
    infinite set.

    remove ch100-5 to avoid spam trap
     
    bz, May 18, 2008
    #3
  4. CharlesBlackstone

    hr(bob) Guest

    On May 17, 6:29 pm, bz <> wrote:
    > CharlesBlackstone <> wrote in news:17fdbbc6-
    > :
    >
    >
    >
    >
    >
    > > Thanks for the replies.

    >
    > > I bought this power supply for $300, because I have other uses for it,
    > > such as in my laboratory at work. But in some applications, I will use
    > > it to its max to charger very large battery packs for very large
    > > planes. It is what other people who do what I do buy.

    >
    > > RC battery chargers do not come with power supplies.

    >
    > > This is the charger:

    >
    > >http://www.batteryjunction.com/temilibachwl.html

    >
    > > Thanks for any helpful replies.

    >
    > Your supply seems to have two kinds of limits.
    > Voltage and current.
    >
    > This means that you can regulate the 'open circuit voltage'. You would want
    > to make sure that never exceeds your battery voltage by more than a few
    > percent.
    >
    > The current regulation means you can regulate the 'short circuit current'.
    > You would want to make sure this never exceeds the safe charging current
    > for your battery (which should be something on the order of 10% of the
    > discharge current).
    >
    > You should look up the charging conditions for your particular battery,
    > with nothing connected to the supply, set the open circuit voltage.
    > Then, with an amp meter (perhaps the supply has one built in), short the
    > output and set the current to less than the max charging current.
    >
    > NOW, you can connect your battery to be charged.
    >
    > Since you have a 'dumb charger', you will need to monitor the charging to
    > make sure you don't overcharge the battery.
    > If your voltage and current settings are correct, that shouldn't happen,
    > but .... it is better to be safe than sorry.
    >
    > What you do NOT want to do with a TRUE current supply (one that could go to
    > any voltage) would be to open circuit it, because it would go to infinite
    > voltage.
    > What you do NOT want to do with a TRUE voltage supply (one that could go to
    > any current) would be to short the output because the current would be
    > infinite.
    > A supply that regulates BOTH, however, is limited in both and thus kind of
    > the best of both worlds.
    >
    > --
    > bz      73 de N5BZ k
    >
    > please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
    > infinite set.
    >
    >   remove ch100-5 to avoid spam trap- Hide quoted text -
    >
    > - Show quoted text -


    What is the voltage and current that is specified to charge the
    batteries that you are planning to charge????
     
    hr(bob) , May 18, 2008
    #4
  5. CharlesBlackstone

    bz Guest

    "Dave Plowman (News)" <> wrote in
    news::

    > In article <Xns9AA1BC2E27A24WQAHBGMXSZHVspammote@130.39.198.139>,
    > bz <> wrote:
    >> This means that you can regulate the 'open circuit voltage'. You would
    >> want to make sure that never exceeds your battery voltage by more than
    >> a few percent.

    >
    > IMHO the charge voltage is pretty irrelevant. It's the current that
    > matters.


    I agree that the current IS the most relevant parameter.

    The voltage is relevant if there is a cell that is failing or if you want
    to safely charge different kinds of batteries and avoid overcharging.

    There is no harm to limiting the voltage.






    --
    bz 73 de N5BZ k

    please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
    infinite set.

    remove ch100-5 to avoid spam trap
     
    bz, May 18, 2008
    #5
  6. CharlesBlackstone

    Al Guest

    On Sat, 17 May 2008 18:45:15 +0100, Dave Plowman (News) wrote:

    > In article
    > <>,
    > CharlesBlackstone <> wrote:
    >> Hi, I bought a variable voltage variable amp power supply to use
    >> charging my RC batteries:
    >> http://shop.vendio.com/evan2002/item/857080628/index.html

    >
    >> I don't really understand it much though. First, should I never turn it
    >> on if there is no load?

    >
    >> I will use it with either a nicd/nimh charger or a lipoly charger. In
    >> either case, should I turn the voltage to 12 volts, and the amps to the
    >> maximum (10), then turn on the charger? Should the charger be hooked up
    >> and turned on with a battery connected to be charged, before I turn on
    >> the power supply?

    >
    >> Thanks very much in advance for any guidance.

    >
    > Seems to be a very expensive way to buy a battery charger. A bench power
    > supply like this is designed to provide clean stable DC for electronics
    > use - which you pay dearly for. Nor will it monitor the battery
    > condition and adjust the charge to suit.


    OK, this is what you do. You will need a diode with at least a one ampere
    rating. Connect the cathode, that is the lead that is next to the band
    around the body, to the positive binding post. If your batter is rated
    at, say 12 volts, get a 12volt auto lamp rated at one amp, like one for
    the tail light. Hook it to the remaining lead of the diode. Now set the
    voltage on power supply to 13.6 volts. Next connect the positive terminal
    of the battery to the free lead of the lamp. Connect the negative lead to
    the negative binding post.

    If the battery is not charged at all, the lamp will glow brightly as the
    current flows into the battery. It should dim over time as the battery
    charges up. If it doesn't, then the battery may be dead. If you have a
    voltmeter, check the voltage of the battery every now and then. If it
    reaches 13 volts or so, it will be fairly charged.

    If it is a 6 volt battery, get a 6 volt, 1 amp lamp, and set the power
    supply to 7.2 volts.

    Other battery voltages will take other values for the lamp. If you have a
    7.2 battery, put a 6 volt and a 1.5 volt lamp in series. Set the voltage
    to 9 volts on the power supply.

    What does the lamp do for you? It limits the current inrush to a
    discharged battery and gives you a rough idea of the state of charge of
    the battery.

    The diode prevents a mistake where the voltage on the battery is higher
    than that set at your power supply. You don't want the battery to be
    pushing current into your power supply.

    Experiment and have fun!

    Al
     
    Al, May 18, 2008
    #6
  7. CharlesBlackstone

    bz Guest

    "Dave Plowman (News)" <> wrote in
    news::

    > In article <Xns9AA1BC2E27A24WQAHBGMXSZHVspammote@130.39.198.139>,
    > bz <> wrote:
    >> This means that you can regulate the 'open circuit voltage'. You would
    >> want to make sure that never exceeds your battery voltage by more than
    >> a few percent.

    >
    > IMHO the charge voltage is pretty irrelevant. It's the current that
    > matters.
    >


    Here is a current regulator that can be used for 0-2A with supplies that
    don't have current regulation built in.
    http://kd1jv.qrpradio.com/vps/voclps.HTM





    --
    bz

    please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
    infinite set.

    remove ch100-5 to avoid spam trap
     
    bz, May 19, 2008
    #7
  8. On May 19, 10:07 am, bz <> wrote:
    > "Dave Plowman (News)" <> wrote innews::
    >
    > > In article <Xns9AA1BC2E27A24WQAHBGMXSZHVspamm...@130.39.198.139>,
    > >    bz <> wrote:
    > >> This means that you can regulate the 'open circuit voltage'. You would
    > >> want to make sure that never exceeds your battery voltage by more than
    > >> a few percent.

    >
    > > IMHO the charge voltage is pretty irrelevant. It's the current that
    > > matters.

    >
    > Here is a current regulator that can be used for 0-2A with supplies that
    > don't have current regulation built in.http://kd1jv.qrpradio.com/vps/voclps.HTM
    >
    > --
    > bz
    >
    > please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
    > infinite set.
    >
    >   remove ch100-5 to avoid spam trap


    Hey thanks everyone for all the great answers. I have been busy and
    not returned (and I thought the thread had sort of faded away).

    bz, what is the purpose of regulating the current, when the power
    supply can supply current from 0 to 10 amps (or if I parallel the two
    PS in it, 20 amps)?

    Al, thanks. When people charge batteries directly with these PSs they
    do use a diode. I may do that eventually but for the moment am using
    the PS to power pretty smart chargers. In that situation your idea of
    having the bulb in circuit is brilliant, it's a way to monitor charge
    status. Cool.

    Mike, this is down the road, and why I got this monster:
    http://www.youtube.com/watch?v=bSfTx4csNsw
    Thats' 44 volts he's putting in those batteries starting at 10 amps,
    and as you can see it just takes a few minutes to replenish a pack
    that holds 2300 mah. The objective is to charge a pack in the same
    amount of time it will keep your plane in the air, so with a couple
    batteries and the Mastech PS, you can fly all day. People either use a
    Honda generator/inverter or a couple deep cycle marine batteries with
    an inverter. This is not a cheap hobby. Probably more than you wanted
    to know but.....

    Thanks to your help I set the voltage at a little over 12 (since I
    dont' have a diode between charger and PS), put the amps at max,
    turned the PS on, connected it to the charger which was already
    connected to the battery, and the charger nicely started pulse
    charging the nimh transmitter pack. I'm so new to this stuff I was
    afraid to turn the Mastech on which I just got. All is good now.

    Wow, this is a great group and lot's of nice folks, I'll come back for
    help and let you know how my learning curve goes.


    Jim
     
    CharlesBlackstone, May 27, 2008
    #8
  9. On May 17, 11:45 am, "Dave Plowman (News)" <>
    wrote:
    > In article
    > <>,
    >    CharlesBlackstone <> wrote:
    >
    > > Hi, I bought a variable voltage variable amp power supply to use
    > > charging my RC batteries:
    > >http://shop.vendio.com/evan2002/item/857080628/index.html
    > > I don't really understand it much though. First, should I never turn
    > > it on if there is no load?
    > > I will use it with either a nicd/nimh charger or a lipoly charger. In
    > > either case, should I turn the voltage to 12 volts, and the amps to
    > > the maximum (10), then turn on the charger? Should the charger be
    > > hooked up and turned on with a battery connected to be charged, before
    > > I turn on the power supply?
    > > Thanks very much in advance for any guidance.

    >
    > Seems to be a very expensive way to buy a battery charger. A bench power
    > supply like this is designed to provide clean stable DC for electronics
    > use - which you pay dearly for. Nor will it monitor the battery condition
    > and adjust the charge to suit.
    >
    > --
    > *Some people are only alive because it is illegal to kill.
    >
    >     Dave Plowman                   London SW
    >                   To e-mail, change noise into sound.


    Hi Dave, I know what you mean by expensive, but this Chinese Mastech
    switching triple power supply (30v10a cccv, 30v10a cccv, constant 5v)
    cost less than $300. I looked up the price of a similar Agilent or
    Tektronics PS and they were about 1500 percent of that.

    Jim
     
    CharlesBlackstone, May 27, 2008
    #9
  10. CharlesBlackstone

    bz Guest

    CharlesBlackstone <> wrote in
    news::

    > On May 19, 10:07 am, bz <> wrote:
    >> "Dave Plowman (News)" <> wrote
    >> innews:4fa14a16d7dave@d

    > avenoise.co.uk:
    >>
    >> > In article <Xns9AA1BC2E27A24WQAHBGMXSZHVspamm...@130.39.198.139>,
    >> >    bz <> wrote:
    >> >> This means that you can regulate the 'open circuit voltage'. You
    >> >> would want to make sure that never exceeds your battery voltage by
    >> >> more than a few percent.

    >>
    >> > IMHO the charge voltage is pretty irrelevant. It's the current that
    >> > matters.

    >>
    >> Here is a current regulator that can be used for 0-2A with supplies
    >> that don't have current regulation built
    >> in.http://kd1jv.qrpradio.com/vps/voclp

    > s.HTM


    >
    > Hey thanks everyone for all the great answers. I have been busy and
    > not returned (and I thought the thread had sort of faded away).
    >
    > bz, what is the purpose of regulating the current, when the power
    > supply can supply current from 0 to 10 amps (or if I parallel the two
    > PS in it, 20 amps)?


    I was assuming directly charging batteries from a DC power supply.

    If you have a supply that has an adjustable current regulator built in,
    the cicuit I showed is not needed. I didn't look at the specs on YOUR
    supply so I was just giving a link to a nice current regulator I had seen.
    If you were charging batteries directly from a voltage regulated supply,
    without any current regulation or limiting, you can damage your batteries.

    .....

    > Thanks to your help I set the voltage at a little over 12 (since I
    > dont' have a diode between charger and PS), put the amps at max,


    Check the specs for the batteries you are charging and be sure that you
    never exceed the 'maximum charging current' ratings. Otherwise you will
    damage your batteries and shorten their life.

    I had a small battery blow up when I tried to recharge it.


    > turned the PS on, connected it to the charger which was already
    > connected to the battery, and the charger nicely started pulse
    > charging the nimh transmitter pack.


    You have a charger that is [I assume] designed for the batteries you are
    using. Its job is to regulate the current flow so as to charge as fast as
    possible without damage to the battery.


    > I'm so new to this stuff I was
    > afraid to turn the Mastech on which I just got. All is good now.
    >
    > Wow, this is a great group and lot's of nice folks, I'll come back for
    > help and let you know how my learning curve goes.


    Good luck and be careful.



    --
    bz 73 de N5BZ k

    please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
    infinite set.

    remove ch100-5 to avoid spam trap
     
    bz, May 27, 2008
    #10
  11. On May 27, 6:11 am, bz <> wrote:
    > CharlesBlackstone <> wrote innews::
    >
    >
    >
    >
    >
    > > On May 19, 10:07 am, bz <> wrote:
    > >> "Dave Plowman (News)" <> wrote
    > >> innews:4fa14a16d7dave@d

    > > avenoise.co.uk:

    >
    > >> > In article <Xns9AA1BC2E27A24WQAHBGMXSZHVspamm...@130.39.198.139>,
    > >> >    bz <> wrote:
    > >> >> This means that you can regulate the 'open circuit voltage'. You
    > >> >> would want to make sure that never exceeds your battery voltage by
    > >> >> more than a few percent.

    >
    > >> > IMHO the charge voltage is pretty irrelevant. It's the current that
    > >> > matters.

    >
    > >> Here is a current regulator that can be used for 0-2A with supplies
    > >> that don't have current regulation built
    > >> in.http://kd1jv.qrpradio.com/vps/voclp

    > > s.HTM

    >
    > > Hey thanks everyone for all the great answers. I have been busy and
    > > not returned (and I thought the thread had sort of faded away).

    >
    > > bz, what is the purpose of regulating the current, when the power
    > > supply can supply current from 0 to 10 amps (or if I parallel the two
    > > PS in it, 20 amps)?

    >
    > I was assuming directly charging batteries from a DC power supply.
    >
    > If you have a supply that has an adjustable current regulator built in,
    > the cicuit I showed is not needed. I didn't look at the specs on YOUR
    > supply so I was just giving a link to a nice current regulator I had seen.
    > If you were charging batteries directly from a voltage regulated supply,
    > without any current regulation or limiting, you can damage your batteries.
    >
    > ....
    >
    > > Thanks to your help I set the voltage at a little over 12 (since I
    > > dont' have a diode between charger and PS), put the amps at max,

    >
    > Check the specs for the batteries you are charging and be sure that you
    > never exceed the 'maximum charging current' ratings. Otherwise you will
    > damage your batteries and shorten their life.
    >
    > I had a small battery blow up when I tried to recharge it.
    >
    > > turned the PS on, connected it to the charger which was already
    > > connected to the battery, and the charger nicely started pulse
    > > charging the nimh transmitter pack.

    >
    > You have a charger that is [I assume] designed for the batteries you are
    > using. Its job is to regulate the current flow so as to charge as fast as
    > possible without damage to the battery.
    >
    > > I'm so new to this stuff I was
    > > afraid to turn the Mastech on which I just got. All is good now.

    >
    > > Wow, this is a great group and lot's of nice folks, I'll come back for
    > > help and let you know how my learning curve goes.

    >
    > Good luck and be careful.
    >
    > --
    > bz      73 de N5BZ k
    >
    > please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
    > infinite set.
    >
    >   remove ch100-5 to avoid spam trap- Hide quoted text -
    >
    > - Show quoted text -


    Thanks, will do, same to you.
     
    CharlesBlackstone, May 29, 2008
    #11
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