On Jun 26, 8:04=A0pm, lili...@[EMAIL PROTECTED]
wrote:
> On Jun 26, 6:23 pm, Peter Bennett <pete...@[EMAIL PROTECTED]
> wrote:
>
>
>
>
>
> > On Thu, 26 Jun 2008 14:09:18 -0700 (PDT), lili...@[EMAIL PROTECTED]
wrote:
> > >On Jun 26, 4:43 pm, mrdarr...@[EMAIL PROTECTED]
wrote:
> > >> On Jun 26, 1:16 pm, lili...@[EMAIL PROTECTED]
wrote:
>
> > >> > On Jun 26, 4:10 pm, mrdarr...@[EMAIL PROTECTED]
wrote:
>
> > >> > > On Jun 26, 12:20 pm, lili...@[EMAIL PROTECTED]
wrote:
>
> > >> > > > Hello everybody,
>
> > >> > > > I have a set of battery, but I only one hooked up to the
circu=
it, The
> > >> > > > other one act as a backup. I want to implement an electronic
u=
nit that
> > >> > > > will change (swap) the batteries.Therefore the wiring will
nee=
d to be
> > >> > > > changed. The circuit need to sup****t 5amp of continuous
curren=
t. Here
> > >> > > > is what I want to implement.
> > >> > > > from:
> > >> > > > A to C
> > >> > > > B to D
>
> > >> > > > to:
> > >> > > > A to D
> > >> > > > B to C
>
> > >> > > > Is it better to use a analogue or digital switching approach.
=
I am
> > >> > > > just worried that digital might take too much energy by
keepin=
g those
> > >> > > > transistor or mosfet open and close.
>
> > >> > > > Li
>
> > >> > > You mean something like this? =A0(view in fixed-width font, for
=
example,
> > >> > > with Notepad)
>
> > >> > > +---+ =A0 =A0 =A0 =A0 =A0 =A0+----+ =A0 =A0 =A0 =A0 =A0
=A0+---+
> > >> > > |(+)|--switch A--| =A0 =A0|--switch C--|(+)|
> > >> > > | =A0 | =A0 =A0 =A0 =A0 =A0 =A0|Load| =A0 =A0 =A0 =A0 =A0 =A0|
=
=A0 |
> > >> > > | =A0 | =A0 =A0 =A0 =A0 =A0 =A0| =A0 =A0| =A0 =A0 =A0 =A0 =A0 =
=A0| =A0 |
> > >> > > |(-)|--switch B--| =A0 =A0|--switch D--| =A0 |
> > >> > > +---- =A0 =A0 =A0 =A0 =A0 =A0+----+ =A0 =A0 =A0 =A0 =A0
=A0+---+
>
> > >> > > Batt 1 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0
B=
att 2
>
> > >> > Michael, This is basically what I want to do.
> > >> > The battery will run a very small motor and a light.
>
> > >> > Li
>
> > >> Looks like a double-pole-double-throw switch will work
>
> > >> see =A0http://en.wikipedia.org/wiki/Switch
> > >> look under DPDT
>
> > >> seems simpler than a MOSFET solution.
>
> > >> When exactly do you want to switch?
>
> > >> Michael
>
> > >This was one of the initial idea, Maybe have a servo motor to control
> > >the switch. =A0( and a PIC chip to supervise the whole operation)
> > >K
>
> > Use a relay - that's an electrically controlled switch.
>
> > There is probably no need to switch both positive and negative
> > terminals - using an SPDT switch in the positive leads would likely be
> > sufficient.
>
> > An output of a PIC probably won't drive a 5 amp relay directly, so you
> > would have to have the PIC drive a transistor or small relay, which
> > would drive the large relay.
>
> > --
> > Peter Bennett, VE7CEI
> > peterbb4 (at) interchange.ubc.ca
> > GPS and NMEA info:http://vancouver-webpages.com/peter
> > Vancouver Power Squadron:http://vancouver.powersquadron.ca
>
> would there be anything else beside a relay?
> that would require energy only when switching is required?
>
> Li- Hide quoted text -
>
> - Show quoted text -
Try looking up a "latching relay". They only require power when
they're switching. Driving a 5A load is going to require a realy with
at least a 1 watt coil, so you'll need two transistors to drive the
two coils from the PIC.
Cheers
Chris
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