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OT - Litrhium versus Ni Cad — Parallax Forums

OT - Litrhium versus Ni Cad

ArchiverArchiver Posts: 46,084
edited 2004-02-27 22:41 in General Discussion
Gentlemen:

I know this is OT but I thought I would ask.

I recently purchase a magnetometer. It uses a soldered in place
Lithium battery (3.5 vdc) to keep the internal Julian clock active when
not being powered. I wish to replace the dead battery with a Ni-Cad
(3.6vdc) that I can quickly replace when it is expired. This modification
will save me from disassembling the unit just to replace the battery.
The manufacturer of the magnetometer claims that the Lithium battery
(an AA size) should be replaced every 6 to 10 years.

Does anyone have any suggestions on why I shouldn't make this
conversion? I know the voltages are different. Should that make
any difference?

Thank you for your replies.

Dick
KF4DSL


[noparse][[/noparse]Non-text portions of this message have been removed]

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-02-27 15:45
    Is there a current concern? If the li will last 6 years, I imagine the draw
    must be low.
    As I understand, NiCads can source a greater level of current. Lithiums have a
    high
    capacity is the current draw is small.

    Since the actual voltage of a battery can be be above above nomimal, it would
    seem
    that your magnetometer should be able to deal with a slightly higher voltage.

    Paul

    > Gentlemen:
    >
    > I know this is OT but I thought I would ask.
    >
    > I recently purchase a magnetometer. It uses a soldered in place
    > Lithium battery (3.5 vdc) to keep the internal Julian clock active when
    > not being powered. I wish to replace the dead battery with a Ni-Cad
    > (3.6vdc) that I can quickly replace when it is expired. This modification
    > will save me from disassembling the unit just to replace the battery.
    > The manufacturer of the magnetometer claims that the Lithium battery
    > (an AA size) should be replaced every 6 to 10 years.
    >
    > Does anyone have any suggestions on why I shouldn't make this
    > conversion? I know the voltages are different. Should that make
    > any difference?
    >
    > Thank you for your replies.
    >
    > Dick
    > KF4DSL
    >
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and Body
    of the message will be ignored.
    >
    > Yahoo! Groups Links
    >
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-27 16:53
    Yes, there is a very good reason NOT to do this.
    NiCad's self-discharge themselves. You can't
    really expect a NiCad charge to last more than
    3 months, unless you have some kind of charging
    circuit on it.

    Since the original circuit was designed for
    a Lithium cell, it is very safe to assume there
    is no charging circuit -- so you'll have to
    replace the NiCad every 3 months with a fully
    charged NiCad.

    It makes LOTS more sense to replace the Lithium
    with the appropriate Lithium, and then wait
    another 6 to 12 years.

    --- In basicstamps@yahoogroups.com, <verhap@o...> wrote:
    > Is there a current concern? If the li will last 6 years, I imagine
    the draw must be low.
    > As I understand, NiCads can source a greater level of current.
    Lithiums have a high
    > capacity is the current draw is small.
    >
    > Since the actual voltage of a battery can be be above above
    nomimal, it would seem
    > that your magnetometer should be able to deal with a slightly
    higher voltage.
    >
    > Paul
    >
    > > Gentlemen:
    > >
    > > I know this is OT but I thought I would ask.
    > >
    > > I recently purchase a magnetometer. It uses a soldered in place
    > > Lithium battery (3.5 vdc) to keep the internal Julian clock
    active when
    > > not being powered. I wish to replace the dead battery with a Ni-
    Cad
    > > (3.6vdc) that I can quickly replace when it is expired. This
    modification
    > > will save me from disassembling the unit just to replace the
    battery.
    > > The manufacturer of the magnetometer claims that the Lithium
    battery
    > > (an AA size) should be replaced every 6 to 10 years.
    > >
    > > Does anyone have any suggestions on why I shouldn't make this
    > > conversion? I know the voltages are different. Should that make
    > > any difference?
    > >
    > > Thank you for your replies.
    > >
    > > Dick
    > > KF4DSL
    > >
    > >
    > > [noparse][[/noparse]Non-text portions of this message have been removed]
    > >
    > >
    > >
    > > To UNSUBSCRIBE, just send mail to:
    > > basicstamps-unsubscribe@yahoogroups.com
    > > from the same email address that you subscribed. Text in the
    Subject and Body of the message will be ignored.
    > >
    > > Yahoo! Groups Links
    > >
    > >
    > >
    > >
    > >
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-27 22:41
    To Allan and All That Answered:

    Thank you gentlemen for your replies.

    I took Mr. Lanes' advice and went back to RS to check for additional Lithium
    batteries and I located a 3.6vdc size AA. I also purchase a single AA sized
    battery holder and installed it in my magnetometer it works fine.

    Thanks again. This is a great group. I've been here for 4 years.

    Dick
    KF4DSL

    Original Message
    From: Allan Lane <allan.lane@h...>
    To: <basicstamps@yahoogroups.com>
    Sent: Friday, February 27, 2004 11:53 AM
    Subject: [noparse][[/noparse]basicstamps] Re: OT - Litrhium versus Ni Cad


    > Yes, there is a very good reason NOT to do this.
    > NiCad's self-discharge themselves. You can't
    > really expect a NiCad charge to last more than
    > 3 months, unless you have some kind of charging
    > circuit on it.
    >
    > Since the original circuit was designed for
    > a Lithium cell, it is very safe to assume there
    > is no charging circuit -- so you'll have to
    > replace the NiCad every 3 months with a fully
    > charged NiCad.
    >
    > It makes LOTS more sense to replace the Lithium
    > with the appropriate Lithium, and then wait
    > another 6 to 12 years.
    >
    > --- In basicstamps@yahoogroups.com, <verhap@o...> wrote:
    > > Is there a current concern? If the li will last 6 years, I imagine
    > the draw must be low.
    > > As I understand, NiCads can source a greater level of current.
    > Lithiums have a high
    > > capacity is the current draw is small.
    > >
    > > Since the actual voltage of a battery can be be above above
    > nomimal, it would seem
    > > that your magnetometer should be able to deal with a slightly
    > higher voltage.
    > >
    > > Paul
    > >
    > > > Gentlemen:
    > > >
    > > > I know this is OT but I thought I would ask.
    > > >
    > > > I recently purchase a magnetometer. It uses a soldered in place
    > > > Lithium battery (3.5 vdc) to keep the internal Julian clock
    > active when
    > > > not being powered. I wish to replace the dead battery with a Ni-
    > Cad
    > > > (3.6vdc) that I can quickly replace when it is expired. This
    > modification
    > > > will save me from disassembling the unit just to replace the
    > battery.
    > > > The manufacturer of the magnetometer claims that the Lithium
    > battery
    > > > (an AA size) should be replaced every 6 to 10 years.
    > > >
    > > > Does anyone have any suggestions on why I shouldn't make this
    > > > conversion? I know the voltages are different. Should that make
    > > > any difference?
    > > >
    > > > Thank you for your replies.
    > > >
    > > > Dick
    > > > KF4DSL
    > > >
    > > >
    > > > [noparse][[/noparse]Non-text portions of this message have been removed]
    > > >
    > > >
    > > >
    > > > To UNSUBSCRIBE, just send mail to:
    > > > basicstamps-unsubscribe@yahoogroups.com
    > > > from the same email address that you subscribed. Text in the
    > Subject and Body of the message will be ignored.
    > > >
    > > > Yahoo! Groups Links
    > > >
    > > >
    > > >
    > > >
    > > >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    > Yahoo! Groups Links
    >
    >
    >
    >
    >
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