I'm trying to locate an emergemcy source of power to operate my 2meter
base rig in the event of a power outage. My HTX-242 manual states the
current drain of the transmitter as 8A @ 45W and 4A @ 10W. Would a 17aH
jump start battery work? Or is there something better, yet not to costly?

On Sun, 28 Mar 2004 11:09:13 -0500, "KC8WVG , Bill"
wrote:

I'm trying to locate an emergemcy source of power to operate my 2meter
base rig in the event of a power outage. My HTX-242 manual states the
current drain of the transmitter as 8A @ 45W and 4A @ 10W. Would a 17aH
jump start battery work? Or is there something better, yet not to costly?

Yes it will. It is a nice package for the battery, and has many other
uses as well.

If you do the math, you will get close to two days operation on a
5/5/90 duty cycle.

However, you may wish to add something like an Anderson PowerPole
connector, as the ciggy lighter outlet and plug may not be happy with
the 10 Amp draw (rounding up a little for good luck).

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

On Sun, 28 Mar 2004 11:09:13 -0500, "KC8WVG , Bill"
wrote:

I'm trying to locate an emergemcy source of power to operate my 2meter
base rig in the event of a power outage. My HTX-242 manual states the
current drain of the transmitter as 8A @ 45W and 4A @ 10W. Would a 17aH
jump start battery work? Or is there something better, yet not to costly?

Yes it will. It is a nice package for the battery, and has many other
uses as well.

If you do the math, you will get close to two days operation on a
5/5/90 duty cycle.

However, you may wish to add something like an Anderson PowerPole
connector, as the ciggy lighter outlet and plug may not be happy with
the 10 Amp draw (rounding up a little for good luck).

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

KC8WVG , Bill wrote:


I'm trying to locate an emergemcy source of power to operate my 2meter
base rig in the event of a power outage. My HTX-242 manual states the
current drain of the transmitter as 8A @ 45W and 4A @ 10W. Would a 17aH
jump start battery work? Or is there something better, yet not to costly?

This transceiver is being used for voice, right?

Figure worst case you'll be transmitting 20 percent of the time at 45
Watts, receiving (with squelch open) 75 percent of the time, and in
standby (with squelch closed) 5 percent. Standby current is 0.5 A;
let's assume receive current as 1.2 A. At 45 Watts, your average
transmit current will be 0.2*8, or 1.6 A. Your average receive current
will be 1.2*.75, or 0.9 A. Your average standby current will be 0.5*0.05,
or 0.025 A. Add them all up, and you get 2.525 Amps as an average. This
is approximately 5.5 hours from your prototypical 17 AH "jump start battery",
based on the most common rate for calculation AH capacity being one that
discharges the battery over 20 hours and the fact that your average current
draw is a little more than three times that rate. The figure of 5.5 hours
does include a fudge factor as well.

Best case (you're not NCS, just calling in and responding when NCS calls
you), figure 10 percent transmit at 10 Watts, 10 percent receive, and 80
percent standby. Your average transmit current becomes 0.1*4, or 0.4.
Your average receive current becomes 0.1*1.2, or 0.12. Your average
standby current becomes 0.5*0.8, or 0.4. Average current is now 0.4 +
0.12 + 0.4, or 0.92 Amps. A straight-line approximation shows a
discharge time of 18.48 hours under this load. You could reasonably
expect 18 hours under this best-case scenario.

disclaimer
If this is a critical application you might want to consult with someone
who does these calculations for profit. I just do them for fun.
/disclaimer

Bottom line is if you expect power to be out more than 5.5 hours and to
impose heavy loads on your backup battery then you'll need either more
battery or a photovoltaic system to help keep it topped up under load,
while if you expect power to be out less than 18 hours and to impose
only light loads on your backup battery then your 17 AH jump start
battery should be adequate.

HTH
--
To design the perfect anti-Unix, write an operating system that thinks
it knows what you're doing better than you do. And then adds injury to
insult by getting it wrong.
- esr

KC8WVG , Bill wrote:


I'm trying to locate an emergemcy source of power to operate my 2meter
base rig in the event of a power outage. My HTX-242 manual states the
current drain of the transmitter as 8A @ 45W and 4A @ 10W. Would a 17aH
jump start battery work? Or is there something better, yet not to costly?

This transceiver is being used for voice, right?

Figure worst case you'll be transmitting 20 percent of the time at 45
Watts, receiving (with squelch open) 75 percent of the time, and in
standby (with squelch closed) 5 percent. Standby current is 0.5 A;
let's assume receive current as 1.2 A. At 45 Watts, your average
transmit current will be 0.2*8, or 1.6 A. Your average receive current
will be 1.2*.75, or 0.9 A. Your average standby current will be 0.5*0.05,
or 0.025 A. Add them all up, and you get 2.525 Amps as an average. This
is approximately 5.5 hours from your prototypical 17 AH "jump start battery",
based on the most common rate for calculation AH capacity being one that
discharges the battery over 20 hours and the fact that your average current
draw is a little more than three times that rate. The figure of 5.5 hours
does include a fudge factor as well.

Best case (you're not NCS, just calling in and responding when NCS calls
you), figure 10 percent transmit at 10 Watts, 10 percent receive, and 80
percent standby. Your average transmit current becomes 0.1*4, or 0.4.
Your average receive current becomes 0.1*1.2, or 0.12. Your average
standby current becomes 0.5*0.8, or 0.4. Average current is now 0.4 +
0.12 + 0.4, or 0.92 Amps. A straight-line approximation shows a
discharge time of 18.48 hours under this load. You could reasonably
expect 18 hours under this best-case scenario.

disclaimer
If this is a critical application you might want to consult with someone
who does these calculations for profit. I just do them for fun.
/disclaimer

Bottom line is if you expect power to be out more than 5.5 hours and to
impose heavy loads on your backup battery then you'll need either more
battery or a photovoltaic system to help keep it topped up under load,
while if you expect power to be out less than 18 hours and to impose
only light loads on your backup battery then your 17 AH jump start
battery should be adequate.

HTH
--
To design the perfect anti-Unix, write an operating system that thinks
it knows what you're doing better than you do. And then adds injury to
insult by getting it wrong.
- esr

KC8WVG , Bill wrote:
I'm trying to locate an emergemcy source of power to operate my 2meter
base rig in the event of a power outage. My HTX-242 manual states the
current drain of the transmitter as 8A @ 45W and 4A @ 10W. Would a 17aH
jump start battery work? Or is there something better, yet not to costly?


I'd be interested to hear peoples' thoughts on what constitutes a
2-meter emergency during a power outage.
In winter, I'm most concerned about the gas heat not working and the
pipes freezing. Conversely, in summer, I worry about the freezer
thawing. Being able to talk to the same two guys I talk to every day
on 2-meters is NOT a priority. A power outage is a great time for a
nap...maybe even with the old lady...

If you don't already have a rig in the car, it's not too hard to set up
so you can throw it in the car in such an emergency.

A handheld can also serve the emergency needs...and can serve to satisfy
your 2-meter Jones while walking or shopping or whatever else takes you
away from the rig.

The biggest problem with the portable battery station is that you don't
use it...it goes flat...sulphates...and can't hold a charge when you
need it. I charge mine on a regular schedule and it still goes flat...

mike

--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Honda CB-125S $800 in PDX
Yaesu FTV901R Transverter, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

KC8WVG , Bill wrote:
I'm trying to locate an emergemcy source of power to operate my 2meter
base rig in the event of a power outage. My HTX-242 manual states the
current drain of the transmitter as 8A @ 45W and 4A @ 10W. Would a 17aH
jump start battery work? Or is there something better, yet not to costly?


I'd be interested to hear peoples' thoughts on what constitutes a
2-meter emergency during a power outage.
In winter, I'm most concerned about the gas heat not working and the
pipes freezing. Conversely, in summer, I worry about the freezer
thawing. Being able to talk to the same two guys I talk to every day
on 2-meters is NOT a priority. A power outage is a great time for a
nap...maybe even with the old lady...

If you don't already have a rig in the car, it's not too hard to set up
so you can throw it in the car in such an emergency.

A handheld can also serve the emergency needs...and can serve to satisfy
your 2-meter Jones while walking or shopping or whatever else takes you
away from the rig.

The biggest problem with the portable battery station is that you don't
use it...it goes flat...sulphates...and can't hold a charge when you
need it. I charge mine on a regular schedule and it still goes flat...

mike

--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Honda CB-125S $800 in PDX
Yaesu FTV901R Transverter, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

On Sun, 28 Mar 2004 12:11:22 -0800, mike wrote:

I'd be interested to hear peoples' thoughts on what constitutes a
2-meter emergency during a power outage.

As a member of the county emergency services, the problem starts
when the power goes out.

Being able to talk to the same two guys I talk to every day
on 2-meters is NOT a priority.

It is when the "same two guys" are the County Emergency
Manager and the County Communications Officer that such a
facility is necessary.

A power outage is a great time for a nap...maybe even with the old lady...

I don't need a power outage for that.... ggg

The biggest problem with the portable battery station is that you don't
use it...it goes flat...sulphates...and can't hold a charge when you
need it. I charge mine on a regular schedule and it still goes flat...

My station power supply is a Size 31 100 AH Marine Deep Cycle
Gel-Cell battery with continuous float charge (13.5 V) by dual AC
supplies and suitable diode isolation. All equipment runs on 12V,
and all wiring and distribution devices are UL and USCG marine
approved. Gel-cells don't go flat when float-charged and the usual
battery life is about 5 years.

Steady-state (receive-only) draw is 5A (then again I have 3
transceivers, 6 receivers, and 4 TNCs on-line 24/7.

Contrary to what an earlier poster said, such a setup will not
power the station for the number of hours determined by the AH
rating divided by the steady-state load (in my case 100/5 or 20
hours). After about 6 hours, the no-charge battery bus voltage
will drop to about 11.3 volts at which point several 12 V devices
fail to operate and go off-line. That's what standby generators
are for.

--
73 de K2ASP - Phil Kane

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon

On Sun, 28 Mar 2004 12:11:22 -0800, mike wrote:

I'd be interested to hear peoples' thoughts on what constitutes a
2-meter emergency during a power outage.

As a member of the county emergency services, the problem starts
when the power goes out.

Being able to talk to the same two guys I talk to every day
on 2-meters is NOT a priority.

It is when the "same two guys" are the County Emergency
Manager and the County Communications Officer that such a
facility is necessary.

A power outage is a great time for a nap...maybe even with the old lady...

I don't need a power outage for that.... ggg

The biggest problem with the portable battery station is that you don't
use it...it goes flat...sulphates...and can't hold a charge when you
need it. I charge mine on a regular schedule and it still goes flat...

My station power supply is a Size 31 100 AH Marine Deep Cycle
Gel-Cell battery with continuous float charge (13.5 V) by dual AC
supplies and suitable diode isolation. All equipment runs on 12V,
and all wiring and distribution devices are UL and USCG marine
approved. Gel-cells don't go flat when float-charged and the usual
battery life is about 5 years.

Steady-state (receive-only) draw is 5A (then again I have 3
transceivers, 6 receivers, and 4 TNCs on-line 24/7.

Contrary to what an earlier poster said, such a setup will not
power the station for the number of hours determined by the AH
rating divided by the steady-state load (in my case 100/5 or 20
hours). After about 6 hours, the no-charge battery bus voltage
will drop to about 11.3 volts at which point several 12 V devices
fail to operate and go off-line. That's what standby generators
are for.

--
73 de K2ASP - Phil Kane

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon

On Sun, 28 Mar 2004 12:11:22 -0800, mike wrote:

I'd be interested to hear peoples' thoughts on what constitutes a
2-meter emergency during a power outage.
In winter, I'm most concerned about the gas heat not working and the
pipes freezing. Conversely, in summer, I worry about the freezer
thawing. Being able to talk to the same two guys I talk to every day
on 2-meters is NOT a priority. A power outage is a great time for a
nap...maybe even with the old lady...

The concern is not about talking with your buddies on 2M, but for
those who are involved in various emergency communications functions,
including their local Emergency Ops Center, their state's emergency
operations, ARES, MARS, SATERN, Red Cross, etc.

Many hams are involved with these efforts, and many times in natural
(hurricanes) or not so natural (WTC) disasters have been the only
reliable source of communications.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom