switching

Guest
Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li
 
On Jun 26, 12:20 pm, lili...@ymail.com wrote:
Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li
Click to expand...


You mean something like this? (view in fixed-width font, for example,
with Notepad)


+---+ +----+ +---+
|(+)|--switch A--| |--switch C--|(+)|
| | |Load| | |
| | | | | |
|(-)|--switch B--| |--switch D--| |
+---- +----+ +---+

Batt 1 Batt 2


Michael
 
On Jun 26, 4:10 pm, mrdarr...@gmail.com wrote:
On Jun 26, 12:20 pm, lili...@ymail.com wrote:



Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li

You mean something like this? (view in fixed-width font, for example,
with Notepad)

+---+ +----+ +---+
|(+)|--switch A--| |--switch C--|(+)|
| | |Load| | |
| | | | | |
|(-)|--switch B--| |--switch D--| |
+---- +----+ +---+

Batt 1 Batt 2
Click to expand...
Michael, This is basically what I want to do.
The battery will run a very small motor and a light.


Li
 
On Thu, 26 Jun 2008 14:09:18 -0700 (PDT), lilipot@ymail.com wrote:

On Jun 26, 4:43 pm, mrdarr...@gmail.com wrote:
On Jun 26, 1:16 pm, lili...@ymail.com wrote:



On Jun 26, 4:10 pm, mrdarr...@gmail.com wrote:

On Jun 26, 12:20 pm, lili...@ymail.com wrote:

Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li

You mean something like this? (view in fixed-width font, for example,
with Notepad)

+---+ +----+ +---+
|(+)|--switch A--| |--switch C--|(+)|
| | |Load| | |
| | | | | |
|(-)|--switch B--| |--switch D--| |
+---- +----+ +---+

Batt 1 Batt 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 http://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. ( and a PIC chip to supervise the whole operation)
K
Click to expand...
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
 
On Jun 26, 1:16 pm, lili...@ymail.com wrote:
On Jun 26, 4:10 pm, mrdarr...@gmail.com wrote:



On Jun 26, 12:20 pm, lili...@ymail.com wrote:

Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li

You mean something like this? (view in fixed-width font, for example,
with Notepad)

+---+ +----+ +---+
|(+)|--switch A--| |--switch C--|(+)|
| | |Load| | |
| | | | | |
|(-)|--switch B--| |--switch D--| |
+---- +----+ +---+

Batt 1 Batt 2

Michael, This is basically what I want to do.
The battery will run a very small motor and a light.

Li
Click to expand...

Looks like a double-pole-double-throw switch will work

see http://en.wikipedia.org/wiki/Switch
look under DPDT

seems simpler than a MOSFET solution.

When exactly do you want to switch?

Michael
 
On Jun 26, 4:43 pm, mrdarr...@gmail.com wrote:
On Jun 26, 1:16 pm, lili...@ymail.com wrote:



On Jun 26, 4:10 pm, mrdarr...@gmail.com wrote:

On Jun 26, 12:20 pm, lili...@ymail.com wrote:

Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li

You mean something like this? (view in fixed-width font, for example,
with Notepad)

+---+ +----+ +---+
|(+)|--switch A--| |--switch C--|(+)|
| | |Load| | |
| | | | | |
|(-)|--switch B--| |--switch D--| |
+---- +----+ +---+

Batt 1 Batt 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 http://en.wikipedia.org/wiki/Switch
look under DPDT

seems simpler than a MOSFET solution.

When exactly do you want to switch?

Michael
Click to expand...
This was one of the initial idea, Maybe have a servo motor to control
the switch. ( and a PIC chip to supervise the whole operation)
K
 
On Jun 26, 5:09 pm, lili...@ymail.com wrote:
On Jun 26, 4:43 pm, mrdarr...@gmail.com wrote:



On Jun 26, 1:16 pm, lili...@ymail.com wrote:

On Jun 26, 4:10 pm, mrdarr...@gmail.com wrote:

On Jun 26, 12:20 pm, lili...@ymail.com wrote:

Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li

You mean something like this? (view in fixed-width font, for example,
with Notepad)

+---+ +----+ +---+
|(+)|--switch A--| |--switch C--|(+)|
| | |Load| | |
| | | | | |
|(-)|--switch B--| |--switch D--| |
+---- +----+ +---+

Batt 1 Batt 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 http://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. ( and a PIC chip to supervise the whole operation)
K
Click to expand...
What about using a relay instead of a motor?
Again I do not want too much energy loss while the relay is on

Li
 
On Jun 26, 2:32 pm, lili...@ymail.com wrote:
On Jun 26, 5:09 pm, lili...@ymail.com wrote:



On Jun 26, 4:43 pm, mrdarr...@gmail.com wrote:

On Jun 26, 1:16 pm, lili...@ymail.com wrote:

On Jun 26, 4:10 pm, mrdarr...@gmail.com wrote:

On Jun 26, 12:20 pm, lili...@ymail.com wrote:

Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li

You mean something like this? (view in fixed-width font, for example,
with Notepad)

+---+ +----+ +---+
|(+)|--switch A--| |--switch C--|(+)|
| | |Load| | |
| | | | | |
|(-)|--switch B--| |--switch D--| |
+---- +----+ +---+

Batt 1 Batt 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 http://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. ( and a PIC chip to supervise the whole operation)
K

What about using a relay instead of a motor?
Again I do not want too much energy loss while the relay is on

Li
Click to expand...

Relays will need way more power than a MOSFET.

Others will have to provide the MOSFET schematics. I have a hunch
some P-channel MOSFETs may be needed, but I'm a beginner in this area
(and would like to see the experts post their schematics ;-)

Michael
 
On Jun 26, 6:23 pm, Peter Bennett <pete...@somewhere.invalid> wrote:
On Thu, 26 Jun 2008 14:09:18 -0700 (PDT), lili...@ymail.com wrote:
On Jun 26, 4:43 pm, mrdarr...@gmail.com wrote:
On Jun 26, 1:16 pm, lili...@ymail.com wrote:

On Jun 26, 4:10 pm, mrdarr...@gmail.com wrote:

On Jun 26, 12:20 pm, lili...@ymail.com wrote:

Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li

You mean something like this? (view in fixed-width font, for example,
with Notepad)

+---+ +----+ +---+
|(+)|--switch A--| |--switch C--|(+)|
| | |Load| | |
| | | | | |
|(-)|--switch B--| |--switch D--| |
+---- +----+ +---+

Batt 1 Batt 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 http://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. ( 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
Click to expand...
would there be anything else beside a relay?
that would require energy only when switching is required?

Li
 
On Jun 26, 8:04 pm, lili...@ymail.com wrote:
On Jun 26, 6:23 pm, Peter Bennett <pete...@somewhere.invalid> wrote:





On Thu, 26 Jun 2008 14:09:18 -0700 (PDT), lili...@ymail.com wrote:
On Jun 26, 4:43 pm, mrdarr...@gmail.com wrote:
On Jun 26, 1:16 pm, lili...@ymail.com wrote:

On Jun 26, 4:10 pm, mrdarr...@gmail.com wrote:

On Jun 26, 12:20 pm, lili...@ymail.com wrote:

Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li

You mean something like this?  (view in fixed-width font, for example,
with Notepad)

+---+            +----+            +---+
|(+)|--switch A--|    |--switch C--|(+)|
|   |            |Load|            |   |
|   |            |    |            |   |
|(-)|--switch B--|    |--switch D--|   |
+----            +----+            +---+

Batt 1                             Batt 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  http://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.  ( 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 -
Click to expand...
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
 
On Jun 26, 9:55 pm, Chris <cfoley1...@yahoo.com> wrote:
On Jun 26, 8:04 pm, lili...@ymail.com wrote:



On Jun 26, 6:23 pm, Peter Bennett <pete...@somewhere.invalid> wrote:

On Thu, 26 Jun 2008 14:09:18 -0700 (PDT), lili...@ymail.com wrote:
On Jun 26, 4:43 pm, mrdarr...@gmail.com wrote:
On Jun 26, 1:16 pm, lili...@ymail.com wrote:

On Jun 26, 4:10 pm, mrdarr...@gmail.com wrote:

On Jun 26, 12:20 pm, lili...@ymail.com wrote:

Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li

You mean something like this? (view in fixed-width font, for example,
with Notepad)

+---+ +----+ +---+
|(+)|--switch A--| |--switch C--|(+)|
| | |Load| | |
| | | | | |
|(-)|--switch B--| |--switch D--| |
+---- +----+ +---+

Batt 1 Batt 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 http://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. ( 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
Click to expand...
Hi,
That seems to be a good idea. I found this part SP4-L2-DC12V at
digikey. But I have not seen any latching relay able to support 6 amp
or something like 740watt (1 HP)

Li
 
<lilipot@ymail.com> wrote in message
news:6a84cf26-14a0-4155-af9a-15c5854eb8da@e53g2000hsa.googlegroups.com...
Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li
Click to expand...

Use a push-pull solenoid, tied to the end of a dpdt toggle switch...

It is a "do it yourself" latching relay with an arbitrary current carrying
capability.

Regards,
Bob Monsen
 
On Thu, 26 Jun 2008 18:04:07 -0700 (PDT), lilipot@ymail.com wrote:

On Jun 26, 6:23 pm, Peter Bennett <pete...@somewhere.invalid> wrote:

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
Click to expand...
Another thought: Is there any reason you can't just connect the two
batteries in parallel, and to the load. You will get the same total
run time as you would using one battery, then switching to the other
when the first is discharged.

In many applications, it is recommended that all available batteries
should be connected and used/charged in parallel, rather than
discharging part of the battery bank, then switching to the other
part. This (use all in parallel) will generally result in a smaller
depth-of-discharge of all the batteries, increasing their life (since
depth-of-discharge is what usually kills rechargeable batteries.)


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
 
Chris wrote:
On Jun 26, 8:04 pm, lili...@ymail.com wrote:

On Jun 26, 6:23 pm, Peter Bennett <pete...@somewhere.invalid> wrote:






On Thu, 26 Jun 2008 14:09:18 -0700 (PDT), lili...@ymail.com wrote:

On Jun 26, 4:43 pm, mrdarr...@gmail.com wrote:

On Jun 26, 1:16 pm, lili...@ymail.com wrote:

On Jun 26, 4:10 pm, mrdarr...@gmail.com wrote:

On Jun 26, 12:20 pm, lili...@ymail.com wrote:

Hello everybody,

I have a set of battery, but I only one hooked up to the circuit, The
other one act as a backup. I want to implement an electronic unit that
will change (swap) the batteries.Therefore the wiring will need to be
changed. The circuit need to support 5amp of continuous current. 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 keeping those
transistor or mosfet open and close.

Li

You mean something like this? (view in fixed-width font, for example,
with Notepad)

+---+ +----+ +---+
|(+)|--switch A--| |--switch C--|(+)|
| | |Load| | |
| | | | | |
|(-)|--switch B--| |--switch D--| |
+---- +----+ +---+

Batt 1 Batt 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 http://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. ( 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
Click to expand...
Actually, there are a number of relays that require well
under 1 watt for the coil that can handle a 5A load.
Digikey, Mouser, Newark - the usual suspects - all
carry them. For example, Mouser part# 653-G2RL-24-DC12 is
a DPDT relay with a 12V 33.33 mA (~.4 watts) coil, and has
contacts rated 8 amps at 30 VDC. Even Allelectronics
carries a few that handle 5 amps at the contacts and
need well under a watt for the coil.

Ed
 
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