Re: [Repeater-Builder] Re: Shutting Down Battery Back up

[Scott Zimmerman]

If you are concerned about your batteries lasting as long as possible when 
running on backup, I would NOT use a relay. Even at 100ma of current draw, 
that's a LOT of current in a backup / solar situation. Since the RF PA only 
draws current when in transmit, (Class 'C') you can hook it directly to the 
battery all the time when line voltage is not present. This can be done 
easily with normally closed contacts on a relay that is fed from the AC 
line.

Have a look at the cutout circuitry of this solar charge controller:
http://www.solorb.com/elect/solarcirc/spc3/

They use a voltage comparator to do the switching. I would think a circuit 
could be designed that simply used a 10V zener diode and a transistor to 
feed the power FET. Probably until you would go through all of that, you 
could have the comparator circuit built and ready to go.

The moral of the story is that a comparator and power FET switch would draw 
FAR less current than using a relay coil. You could also set the comparator 
EXACTLY where you want the circuit to turn off. Be sure that the hysteresis 
resistor is a small enough value so that when the circuit cuts out with the 
transmitter active, it won't turn back on when the battery voltage recovers. 
Of course, this could be tailored to taste.

Scott

Scott Zimmerman
Amateur Radio Call N3XCC
474 Barnett Rd
Boswell, PA 15531

- Original Message - 
From: "Al Wolfe" <[EMAIL PROTECTED]>
To: 
Sent: Tuesday, October 21, 2008 9:15 AM
Subject: [Repeater-Builder] Re: Shutting Down Battery Back up


> Don,
>Low battery voltage shut-down can be done quite simply using three or
> four parts: a normally open contact relay, a resistor, and a cap. The
> battery goes to one side of the N. O. contact and the load (repeater?),
> power supply, and relay coil to the other N. O. contact. The other side of
> the coil goes to ground via a resistor. The resistor value is determined
> empirically and should be selected so that the relay will drop out at 
> about
> ten volts or whatever you decide is the minimum useful voltage. Use a
> variable DC supply to determine the proper resistance value.
>
>You should be able to find a 12 volt relay that needs less than 100 ma.
> through the coil. An appropriate resistance might be 22 or 27 ohms for 
> this
> relay.
>
>A 1000 MFD cap should be in parallel with the resistor so that when
> power is restored from the power supply, full voltage is applied to the
> relay coil for a time to energize it. The resistor also lowers the power
> used by the relay to a degree. The ubiquitous chatter diode across the 
> relay
> coil is a good idea as well.
>
>I have used this method for several applications at work and it is
> virtually fool proof.
>
> Good luck,
> Al, K9SI
>
>
>
>>Now the question and  I have not seen this talked about   I would
>> assume  all I would need is a Normally closed Relay and as the Voltage
>> dropped below >a Certain Level it would open and  just break the
>> connection to the Battery back up ,  Is this the way to do it
>
>
>>Thanks
>
>
>>Don KA9QJG
>
>
>
>
> 
>
>
>
> Yahoo! Groups Links
>
>
>






No virus found in this incoming message.
Checked by AVG - http://www.avg.com
Version: 8.0.173 / Virus Database: 270.8.1/1731 - Release Date: 10/17/2008 
7:01 PM

Re: [Repeater-Builder] Re: Shutting Down Battery Back up

[Camilo So]

Any body know what is the name of relay that have a gear on the side, every 
time the relay energize once it turn the gear and lock the relay position from 
normally close
to open and open to close, I have one of the relay that work that way long time 
ago, maybe its still available today.

73
Camilo


  - Original Message - 
  From: Al Wolfe 
  To: Repeater-Builder@yahoogroups.com 
  Sent: Wednesday, October 22, 2008 10:25 AM
  Subject: [Repeater-Builder] Re: Shutting Down Battery Back up


  Scott,
  You are of course correct about hooking the PA directly to the battery, 
  there being no reason to disconnect it.

  There are undoubtedly many good reasons to consider a more sophisticated 
  disconnect method than the simple relay circuit described when the ulimate 
  in power saving is needed. However, I wonder what percentage of the folks on 
  this list have the technical acumen to design a circuit like this, let alone 
  trying to gather all the parts for it.

  The cutout circuit of the solar charge controller you mention does look 
  interesting and the kit for $55 might easily be adaptable to be used in a 
  repeater disconnect application.

  However, I still feel that the extremely simple relay circuit I 
  described will do the job as it has for me in several applications for many 
  years. With only three or four parts there is very little to fail. When the 
  box it up on the hill I don't want to have to run up there every time there 
  is a nearby lightning strike.

  The 100 ma. figure is typical of some of the Rat Shack relays. There are 
  many that pull much less current available.

  Al, K9SI

  > Re: Shutting Down Battery Back up
  > Posted by: "Scott Zimmerman" [EMAIL PROTECTED] scottn3xcc
  > Date: Tue Oct 21, 2008 8:34 am ((PDT))
  >
  > If you are concerned about your batteries lasting as long as possible when
  > running on backup, I would NOT use a relay. Even at 100ma of current draw,
  > that's a LOT of current in a backup / solar situation. Since the RF PA 
  > only
  > draws current when in transmit, (Class 'C') you can hook it directly to 
  > the
  > battery all the time when line voltage is not present. This can be done
  > easily with normally closed contacts on a relay that is fed from the AC
  > line.
  >
  > Have a look at the cutout circuitry of this solar charge controller:
  > http://www.solorb.com/elect/solarcirc/spc3/
  >
  > They use a voltage comparator to do the switching. I would think a circuit
  > could be designed that simply used a 10V zener diode and a transistor to
  > feed the power FET. Probably until you would go through all of that, you
  > could have the comparator circuit built and ready to go.
  >
  > The moral of the story is that a comparator and power FET switch would 
  > draw
  > FAR less current than using a relay coil. You could also set the 
  > comparator
  > EXACTLY where you want the circuit to turn off. Be sure that the 
  > hysteresis
  > resistor is a small enough value so that when the circuit cuts out with 
  > the
  > transmitter active, it won't turn back on when the battery voltage 
  > recovers.
  > Of course, this could be tailored to taste.
  >
  > Scott
  >
  > Scott Zimmerman
  > Amateur Radio Call N3XCC
  > 474 Barnett Rd
  > Boswell, PA 15531
  >
  > - Original Message - 
  > From: "Al Wolfe" <[EMAIL PROTECTED]>
  > To: 
  > Sent: Tuesday, October 21, 2008 9:15 AM
  > Subject: [Repeater-Builder] Re: Shutting Down Battery Back up
  >
  >
  >> Don,
  >> Low battery voltage shut-down can be done quite simply using three or
  >> four parts: a normally open contact relay, a resistor, and a cap. The
  >> battery goes to one side of the N. O. contact and the load (repeater?),
  >> power supply, and relay coil to the other N. O. contact. The other side 
  >> of
  >> the coil goes to ground via a resistor. The resistor value is determined
  >> empirically and should be selected so that the relay will drop out at
  >> about
  >> ten volts or whatever you decide is the minimum useful voltage. Use a
  >> variable DC supply to determine the proper resistance value.
  >>
  >> You should be able to find a 12 volt relay that needs less than 100 
  >> ma.
  >> through the coil. An appropriate resistance might be 22 or 27 ohms for
  >> this
  >> relay.
  >>
  >> A 1000 MFD cap should be in parallel with the resistor so that when
  >> power is restored from the power supply, full voltage is applied to the
  >> relay coil for a time to energize it. The resistor also lowers the power
  >> used by the relay to a degree. The ubiquitous chatter diode across the
  >> relay
  >> coil is a good idea as well.
  >>
  >> I have used this method for several applications at work and it is
  >> virtually fool proof.
  >>
  >> Good luck,
  >> Al, K9SI
  >>
  >>
  >>
  >>> Now the question and I have not seen this talked about I would
  >>> assume all I would need is a Normally closed Relay and as the Voltage
  >>> dropped below >a Certain L

RE: [Repeater-Builder] Re: Shutting Down Battery Back up

[Jeff DePolo]

> Any body know what is the name of relay that have a gear on 
> the side, every time the relay energize once it turn the gear 
> and lock the relay position from normally close
> to open and open to close, I have one of the relay that work 
> that way long time ago, maybe its still available today.
>  
> 73
> Camilo

Latching relay, still readily available.

--- Jeff WN3A

Re: [Repeater-Builder] Re: Shutting Down Battery Back up

[Mike Morris WA6ILQ]

There are single coil and two coil relays that us a
mechanism to accomplish a latching function.
Any full-line relay catalog will show them.

I've seen the one-coil version called an impulse relay,
a rotary relay, a latching relay and a few other choice
names when the mechanism gets dirty and doesn't
work.

Mike WA6ILQ

At 09:20 AM 10/22/08, you wrote:
Any body know what is the name of relay that have a gear on the 
side, every time the relay energize once it turn the gear and lock 
the relay position from normally close
to open and open to close, I have one of the relay that work that 
way long time ago, maybe its still available today.


73
Camilo


- Original Message -
From: Al Wolfe
To: Repeater-Builder@yahoogroups.com
Sent: Wednesday, October 22, 2008 10:25 AM
Subject: [Repeater-Builder] Re: Shutting Down Battery Back up
Scott,
You are of course correct about hooking the PA directly to the battery,
there being no reason to disconnect it.
There are undoubtedly many good reasons to consider a more sophisticated
disconnect method than the simple relay circuit described when the ulimate
in power saving is needed. However, I wonder what percentage of the folks on
this list have the technical acumen to design a circuit like this, let alone
trying to gather all the parts for it.
The cutout circuit of the solar charge controller you mention does look
interesting and the kit for $55 might easily be adaptable to be used in a
repeater disconnect application.
However, I still feel that the extremely simple relay circuit I
described will do the job as it has for me in several applications for many
years. With only three or four parts there is very little to fail. When the
box it up on the hill I don't want to have to run up there every time there
is a nearby lightning strike.
The 100 ma. figure is typical of some of the Rat Shack relays. There are
many that pull much less current available.
Al, K9SI
> Re: Shutting Down Battery Back up
> Posted by: "Scott Zimmerman" 
[EMAIL PROTECTED] scottn3xcc

> Date: Tue Oct 21, 2008 8:34 am ((PDT))
>
> If you are concerned about your batteries lasting as long as possible when
> running on backup, I would NOT use a relay. Even at 100ma of current draw,
> that's a LOT of current in a backup / solar situation. Since the RF PA
> only
> draws current when in transmit, (Class 'C') you can hook it directly to
> the
> battery all the time when line voltage is not present. This can be done
> easily with normally closed contacts on a relay that is fed from the AC
> line.
>
> Have a look at the cutout circuitry of this solar charge controller:
> 
http://www.solorb.com/elect/solarcirc/spc3/ 


>
> They use a voltage comparator to do the switching. I would think a circuit
> could be designed that simply used a 10V zener diode and a transistor to
> feed the power FET. Probably until you would go through all of that, you
> could have the comparator circuit built and ready to go.
>
> The moral of the story is that a comparator and power FET switch would
> draw
> FAR less current than using a relay coil. You could also set the
> comparator
> EXACTLY where you want the circuit to turn off. Be sure that the
> hysteresis
> resistor is a small enough value so that when the circuit cuts out with
> the
> transmitter active, it won't turn back on when the battery voltage
> recovers.
> Of course, this could be tailored to taste.
>
> Scott
>
> Scott Zimmerman
> Amateur Radio Call N3XCC
> 474 Barnett Rd
> Boswell, PA 15531
>
> - Original Message -
> From: "Al Wolfe" <[EMAIL PROTECTED]>
> To: 
<Repeater-Builder@yahoogroups.com>

> Sent: Tuesday, October 21, 2008 9:15 AM
> Subject: [Repeater-Builder] Re: Shutting Down Battery Back up
>
>
>> Don,
>> Low battery voltage shut-down can be done quite simply using three or
>> four parts: a normally open contact relay, a resistor, and a cap. The
>> battery goes to one side of the N. O. contact and the load (repeater?),
>> power supply, and relay coil to the other N. O. contact. The other side
>> of
>> the coil goes to ground via a resistor. The resistor value is determined
>> empirically and should be selected so that the relay will drop out at
>> about
>> ten volts or whatever you decide is the minimum useful voltage. Use a
>> variable DC supply to determine the proper resistance value.
>>
>> You should be able to find a 12 volt relay that needs less than 100
>> ma.
>> through the coil. An appropriate resistance might be 22 or 27 ohms for
>> this
>> relay.
>>
>> A 1000 MFD cap should be in parallel with the resistor so that when
>> power is restored from the power supply, full voltage is applied to the
>> relay coil for a time to energize it. The resistor also lowers the power
>> used by the relay to a degree. The ubiquitous chatter

Re: [Repeater-Builder] Re: Shutting Down Battery Back up

[Mike Morris WA6ILQ]

At 07:25 AM 10/22/08, you wrote:
>Scott,
> You are of course correct about hooking the PA directly to the battery,
>there being no reason to disconnect it.
>
> There are undoubtedly many good reasons to consider a more sophisticated
>disconnect method than the simple relay circuit described when the ulimate
>in power saving is needed. However, I wonder what percentage of the folks on
>this list have the technical acumen to design a circuit like this, let alone
>trying to gather all the parts for it.

Just buy a LVD module (or a solar charge controller module that has
LVD built in).
Or build the one from the link that was posted.  Or dig through the QST
back issues.  They had an article on one and a parts kit was available.

> The cutout circuit of the solar charge controller you mention does look
>interesting and the kit for $55 might easily be adaptable to be used in a
>repeater disconnect application.

No "might easily be adaptable" about it.  Just hook the Astron to the
solar panel input, the repeater system (less PA deck) to the load terminals
and the battery to the battery terminals.  Adjust the Astron to the proper
float voltage to minimize the heat generation in the charge 
controller section..

> However, I still feel that the extremely simple relay circuit I
>described will do the job as it has for me in several applications for many
>years. With only three or four parts there is very little to fail. When the
>box it up on the hill I don't want to have to run up there every time there
>is a nearby lightning strike.

Most of the solar equipment that I've seen has been designed for that
situation.  Sunny states like Texas and Florida that get lots of lightning
also have lots of solar installations and the solar equipment manufacturers
wouldn't be in business if they didn't offer a product that would stand up
to a distant strike.
.
And you can monitor the status of the unit remotely so if it glitches
you know it. There are points in the circuit you can tap and feed to
digital inputs on the repeater controller.  For example, the courtesy
beep can change from a simple beep to a morse "B" when you are
on battery.

> The 100 ma. figure is typical of some of the Rat Shack relays. There are
>many that pull much less current available.

But can they handle 10a of DC current?  I've seen relays that will handle
10a of AC but only 2a of DC, others that are rated at 10a AC or DC.
I've found that, in general, the higher the DC contact current the larger
the coil.

People have opinions, and I respect yours.   Simple and elegant is good,
but it has to meet the requirements.  And minimizing the 24x7 energy
drain from the battery when the power is off is primary.

My opinion is that once the AC power is off I'd rather NOT waste the
available battery charge feeding as much energy to the LVD relay coil
as I do the receiver and the controller combined (or depending on the
relay coil, as much as twice that).  Power outages can last minutes
or they can last weeks.  Or, as some areas of Louisiana learned after
Katrina,  months.

>Al, K9SI

Mike WA6ILQ