Breakers as Switches - Good Idea?

At 08:55 18 February 2016, Jim White wrote:
At 17:17 17 February 2016, Steve Koerner wrote:
I think the right way to look at this is to take a gander at the spec
sheet=
of the referenced part. At the top of the sheet is a table showing the
re=
sistance that the breaker introduces for varying current ratings. It
shows=
for example that a 5A breaker introduces 0.03 ohms. Next, consider
the
p=
eak load of the device that you're powering. If it's a radio, for
example,=
look at its transmit current. Let's say the peak current is 1 amp.
Then
=
the voltage drop across the breaker is: V =3D iR =3D (1)(.03) =3D 30 mV

=
That's insignificant. The actual effect on battery life is that it will
mo=
re likely be extended by the introduction of the additional load; it's
just=
that the drop out point for the connected instrument will be 30mV lower

=
For a lithium battery with a fairly sharp fall off, I think you'll
normally=
end up net positive to battery life by the introduction of the small
serie=
s load (as long as the connected instrument works down to the steep part
of=
the battery discharge curve). =20

And, BTW, fuses have resistance too -- it's the same game with a fuse.

I was using ETA 106-P30 trips that have internal resistance of 0.9ohm fo
the 1a and 0.05 for the 5 amp. The problem was my Becker radio which onl
likes to work at 12V+. The 5amp breaker dropped the voltage by over 1V o
transmit which for SLA batteries made it unworkable. A standard blade fus
had much less impact.

I now use LifePo4 so this is now a mute point. However one point to not
with trips is the trip time. Mine were 10 seconds at 2x rated load
Standard fuse trips much faster.

If your Becker wont work below 12v there is something odd.

What model is it? The spec for AR6201 (25/8.33KHz) is: Input Voltage
Range: 9 V DC to 32.2 V DC

http://www.becker-avionics.com/ar620...with-8-33-khz/

Jim White wrote on 2/18/2016 12:55 AM:

I was using ETA 106-P30 trips that have internal resistance of 0.9ohm for
the 1a and 0.05 for the 5 amp. The problem was my Becker radio which only
likes to work at 12V+. The 5amp breaker dropped the voltage by over 1V on
transmit which for SLA batteries made it unworkable. A standard blade fuse
had much less impact.

Unless your Becker is about 25+ years old, there is something wrong with
it. For decades, Beckers have worked to 10 volts.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"

https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

If it's rated for use as a switch, sure you can use a breaker as a switch. I have a Tyco breaker that's rated as a switch (looks like a toggle switch) that I bought because when I was planning a FLARM install that was integrated with an LX8080 Simple/V5 I wasn't sure whether the LX delivered switched or unswitched power to the FLARM. As it turned out it delivered switched power so the breaker is on my shelf rather than in the glider. The glider has two aircraft spec breakers on the panel and one built into the battery box. My glider no longer has any master switch as all the avionics have their own built in on/off switches so the only thing the master switch did for me was to present me with the possibility of turning everything off in flight by accident.

At 10:23 18 February 2016, Tim Newport-Peace wrote:
At 08:55 18 February 2016, Jim White wrote:
At 17:17 17 February 2016, Steve Koerner wrote:
I think the right way to look at this is to take a gander at the spec
sheet=
of the referenced part. At the top of the sheet is a table showing
the
re=
sistance that the breaker introduces for varying current ratings. It
shows=
for example that a 5A breaker introduces 0.03 ohms. Next, conside
the
p=
eak load of the device that you're powering. If it's a radio, for
example,=
look at its transmit current. Let's say the peak current is 1 amp.
Then
=
the voltage drop across the breaker is: V =3D iR =3D (1)(.03) =3D 30
mV

=
That's insignificant. The actual effect on battery life is that it
will
mo=

re likely be extended by the introduction of the additional load; it's
just=
that the drop out point for the connected instrument will be 30mV
lower

=
For a lithium battery with a fairly sharp fall off, I think you'll
normally=
end up net positive to battery life by the introduction of the small
serie=
s load (as long as the connected instrument works down to the steep
part
of=
the battery discharge curve). =20

And, BTW, fuses have resistance too -- it's the same game with a fuse.

I was using ETA 106-P30 trips that have internal resistance of 0.9ohm fo
the 1a and 0.05 for the 5 amp. The problem was my Becker radio which onl
likes to work at 12V+. The 5amp breaker dropped the voltage by over 1V o
transmit which for SLA batteries made it unworkable. A standard blade
fus
had much less impact.

I now use LifePo4 so this is now a mute point. However one point to not
with trips is the trip time. Mine were 10 seconds at 2x rated load
Standard fuse trips much faster.

If your Becker wont work below 12v there is something odd.

What model is it? The spec for AR6201 (25/8.33KHz) is: Input Voltag
Range: 9 V DC to 32.2 V DC

http://www.becker-avionics.com/ar620...with-8-33-khz/


4201

At 04:36 19 February 2016, Eric Greenwell wrote:
Jim White wrote on 2/18/2016 12:55 AM:

I was using ETA 106-P30 trips that have internal resistance of 0.9ohm
for
the 1a and 0.05 for the 5 amp. The problem was my Becker radio which
only
likes to work at 12V+. The 5amp breaker dropped the voltage by over 1V
on
transmit which for SLA batteries made it unworkable. A standard blade
fuse
had much less impact.

Unless your Becker is about 25+ years old, there is something wrong with
it. For decades, Beckers have worked to 10 volts.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"

https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

From the installation manual:

'Supply voltage range 12.4 V to 15.1 V '

It will receive below 12V but will not transmit properly.

At 10:27 19 February 2016, Jim White wrote:
At 04:36 19 February 2016, Eric Greenwell wrote:
Jim White wrote on 2/18/2016 12:55 AM:

I was using ETA 106-P30 trips that have internal resistance of 0.9oh
for
the 1a and 0.05 for the 5 amp. The problem was my Becker radio whic
only
likes to work at 12V+. The 5amp breaker dropped the voltage by over 1
on
transmit which for SLA batteries made it unworkable. A standard blade
fuse
had much less impact.

Unless your Becker is about 25+ years old, there is something wrong with

it. For decades, Beckers have worked to 10 volts.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"

https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

From the installation manual:

'Supply voltage range 12.4 V to 15.1 V '

It will receive below 12V but will not transmit properly.

So it IS a 20+ year old design.

You will need to upgrades it to a 8.33KHz model before 2018 anyway.

Pity you missed Becker's trade-in offer.
http://www.becker-avionics.com/wp-co...ion-AR6201.pdf

Give them a call anyway, they may be friendly and make you at least some
offer.

Good luck!

On 2/19/2016 4:07 AM, Tim Newport-Peace wrote:
So it IS a 20+ year old design.

You will need to upgrades it to a 8.33KHz model before 2018 anyway.

Pity you missed Becker's trade-in offer.
http://www.becker-avionics.com/wp-co...ion-AR6201.pdf


--
Dan, 5J

At 15:44 19 February 2016, Dan Marotta wrote:
Give them a call anyway, they may be friendly and make you at least some
offer.

Good luck!

On 2/19/2016 4:07 AM, Tim Newport-Peace wrote:
So it IS a 20+ year old design.

You will need to upgrades it to a 8.33KHz model before 2018 anyway.

Pity you missed Becker's trade-in offer.

http://www.becker-avionics.com/wp-co...ion-AR6201.pdf


--
Dan, 5J

Nonsense. I'll get another 2 years at least out of it. Then new 8.33 radios
will be under $1000

Jim

On Fri, 19 Feb 2016 15:52:42 +0000, Jim White wrote:

At 15:44 19 February 2016, Dan Marotta wrote:
Give them a call anyway, they may be friendly and make you at least some
offer.

Good luck!

On 2/19/2016 4:07 AM, Tim Newport-Peace wrote:
So it IS a 20+ year old design.

You will need to upgrades it to a 8.33KHz model before 2018 anyway.

Pity you missed Becker's trade-in offer.

http://www.becker-avionics.com/wp-co...011/10/150108-
Exchange-action-AR6201.pdf


--
Dan, 5J

Nonsense. I'll get another 2 years at least out of it. Then new 8.33
radios will be under $1000

Some already are. I see that the Dittel KRT2 is already cheaper than when
I bought mine two years back.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |