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Recharging a battery — Parallax Forums

Recharging a battery

ArchiverArchiver Posts: 46,084
edited 2000-05-03 22:15 in General Discussion
William Cox wrote:
>
> 10 farad cap is only a couple of dollars from Digi-Key. The problem is that
> they are only 2.5 volts. You could wire them in series. www.solarbotics.com
> just got in 25 FARAD caps. $25 though [noparse]:)[/noparse]
> -William
>
>
Original Message
> From: Chris <c_rosney@y...>
> To: <basicstamps@egroups.com>
> Sent: Tuesday, May 02, 2000 9:02 PM
> Subject: [noparse][[/noparse]basicstamps] Recharging a battery
>
> > I need to have a stamp powered for 24 hours a day, and the plan is to
> > use a battery supply at night, and a set of photo cells durring the
> > day. What i need to know is how i can recharge the battery through
> > the solar cells once it has become drained. I only want to use
> > regular AA or 9V rechargible batteries, nothing fancy.
> >
> > I know you can also get big (3.3F) capacitors that will do the job
> > quite nice, but i they're kind of expensive, don't last as long and i
> > wanted to know if i could do it using ordinary cells.
> >
> > -Chris
> >
> >
> >
> >
If ye wire them in series, me thinks the capacitance will go down.

1/C = 1/c + 1/c + 1/c
--
Best Regards
Tom Rose
President ETA

For Opacity Training and Measurement Services and Products Visit
http://www.eta-is-opacity.com
For Baghouse Monitors Visit
http://www.tartek.com

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2000-05-03 02:02
    I need to have a stamp powered for 24 hours a day, and the plan is to
    use a battery supply at night, and a set of photo cells durring the
    day. What i need to know is how i can recharge the battery through
    the solar cells once it has become drained. I only want to use
    regular AA or 9V rechargible batteries, nothing fancy.

    I know you can also get big (3.3F) capacitors that will do the job
    quite nice, but i they're kind of expensive, don't last as long and i
    wanted to know if i could do it using ordinary cells.

    -Chris
  • ArchiverArchiver Posts: 46,084
    edited 2000-05-03 02:34
    10 farad cap is only a couple of dollars from Digi-Key. The problem is that
    they are only 2.5 volts. You could wire them in series. www.solarbotics.com
    just got in 25 FARAD caps. $25 though [noparse]:)[/noparse]
    -William
    Original Message
    From: Chris <c_rosney@y...>
    To: <basicstamps@egroups.com>
    Sent: Tuesday, May 02, 2000 9:02 PM
    Subject: [noparse][[/noparse]basicstamps] Recharging a battery


    > I need to have a stamp powered for 24 hours a day, and the plan is to
    > use a battery supply at night, and a set of photo cells durring the
    > day. What i need to know is how i can recharge the battery through
    > the solar cells once it has become drained. I only want to use
    > regular AA or 9V rechargible batteries, nothing fancy.
    >
    > I know you can also get big (3.3F) capacitors that will do the job
    > quite nice, but i they're kind of expensive, don't last as long and i
    > wanted to know if i could do it using ordinary cells.
    >
    > -Chris
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-05-03 16:57
    But the voltage will go up, and I think that's what he wants.
    -William


    > If ye wire them in series, me thinks the capacitance will go down.
    >
    > 1/C = 1/c + 1/c + 1/c
    > --
    > Best Regards
    > Tom Rose
    > President ETA
    >
    > For Opacity Training and Measurement Services and Products Visit
    > http://www.eta-is-opacity.com
    > For Baghouse Monitors Visit
    > http://www.tartek.com
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-05-03 17:06
    On Wed, 3 May 2000, Chris wrote:

    >
    > When you wire capacitors in series, all that happens is the total
    > capacitance drops, and the voltage is still 2.5V.
    >
    > 1/CT = 1/C1 + 1/C2...
    >
    > -Chris

    Quote mode on...
    "Capacitors are used in series to provide a higher breakdown rating for
    the combination. For instance, each of hte three equal capacitances in
    series has one-third the applied voltage."

    Quote mode off.
    3 caps rated at 10uf/15v in series would equal 3.3uf/45v

    Quote from Grob Basic Electronics fourth edition ( don't ask the
    copyright date (-; )

    Hope this helps,

    Dale Harwood [noparse][[/noparse] N4VFF ]

    internet> dale@h...

    ax.25> n4vff@n4vff.#cha.tn.usa.noam

    #include <std_disclaimer.h>
  • ArchiverArchiver Posts: 46,084
    edited 2000-05-03 22:12
    --- In basicstamps@egroups.com, Tom Rose <tomrose@i...> wrote:

    > If ye wire them in series, me thinks the capacitance will go down.
    >
    > 1/C = 1/c + 1/c + 1/c
    > --
    > Best Regards
    > Tom Rose
    > President ETA
    >
    > For Opacity Training and Measurement Services and Products Visit
    > http://www.eta-is-opacity.com
    > For Baghouse Monitors Visit
    > http://www.tartek.com

    You thinks right, but they'd be fine in parallel. But you still can
    only use 2.5 volts. And in any case, two one 1F capacitors will cost
    more than one 2F anyay.

    -Chris
  • ArchiverArchiver Posts: 46,084
    edited 2000-05-03 22:15
    --- In basicstamps@egroups.com, "William Cox" <william@c...> wrote:
    > 10 farad cap is only a couple of dollars from Digi-Key. The problem
    is that
    > they are only 2.5 volts. You could wire them in series.
    www.solarbotics.com
    > just got in 25 FARAD caps. $25 though [noparse]:)[/noparse]
    > -William
    >
    >
    Original Message
    > From: Chris <c_rosney@y...>
    > To: <basicstamps@egroups.com>
    > Sent: Tuesday, May 02, 2000 9:02 PM
    > Subject: [noparse][[/noparse]basicstamps] Recharging a battery
    >
    >

    When you wire capacitors in series, all that happens is the total
    capacitance drops, and the voltage is still 2.5V.

    1/CT = 1/C1 + 1/C2...

    -Chris
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