I'm looking for a portable rechargeable 12-volt battery, probably a gel cell, to
extend my operating time with a VHF/UHF hand-held to about 12 hours of use.
I envision that I could power my radio by connecting its cigarette lighter power
adapter to the portable battery. The portable battery should be comfortable to
carry with me, for example: attached to my belt, or with an over-the-shoulder
strap. Any ideas?
73 de Dick, AC7EL

Dick Grady AC7EL wrote:
I'm looking for a portable rechargeable 12-volt battery, probably a gel cell, to
extend my operating time with a VHF/UHF hand-held to about 12 hours of use.
I envision that I could power my radio by connecting its cigarette lighter power
adapter to the portable battery. The portable battery should be comfortable to
carry with me, for example: attached to my belt, or with an over-the-shoulder
strap. Any ideas?

Estimate the number of hours out of that 12 hours
that you would be transmitting. Multiply that by
the current consumption during transmit. Multiply
the rest of the hours by the current consumption
during receive. Add them together to get an
estimate of the necessary ampere*hour rating
for the gel cell. Be sure to take into account
the minimum operating voltage required by the
hand-held.
--
73, Cecil http://www.w5dxp.com

On Sep 10, 12:49 pm, Dick Grady AC7EL wrote:
I'm looking for a portable rechargeable 12-volt battery, probably a gel cell, to
extend my operating time with a VHF/UHF hand-held to about 12 hours of use.
I envision that I could power my radio by connecting its cigarette lighter power
adapter to the portable battery. The portable battery should be comfortable to
carry with me, for example: attached to my belt, or with an over-the-shoulder
strap. Any ideas?
73 de Dick, AC7EL

I suggest you start he

http://www.batterystuff.com/tutorial_battery.html

Then "run the numbers" per Cecil's post above.

Then Google "Gel Cell Batteries".

http://www.batterystation.com/gelcell.htm

http://www.batterymart.com/c-sealed-...batteries.html

w3rv

In article ,
Cecil Moore wrote:

Estimate the number of hours out of that 12 hours
that you would be transmitting. Multiply that by
the current consumption during transmit. Multiply
the rest of the hours by the current consumption
during receive. Add them together to get an
estimate of the necessary ampere*hour rating
for the gel cell. Be sure to take into account
the minimum operating voltage required by the
hand-held.

.... but do consider the possible benefits of using a lower-voltage
battery. A lot of popular 2-meter HTs will develop a watt or so of
output power on 6 volts, and a couple of watts on 8 volts. You only
need 10-12 volts into the radio if you absolutely insist on getting
the full 5 watts out.

Such an HT, fed from a 6-volt SLA battery, and equipped with a
full-length "spaghetti noodle" whip antenna and a rat-tail wire
counterpoise, would probably outperform the same radio fed from 12
volts but using only the standard lossy "rubber duck" antenna... and
it would do so on both receive and transmit. The battery would weight
only about half as much... or, conversely, would allow for twice the
amp-hour capacity at the same battery weight.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Mon, 10 Sep 2007 13:14:44 EDT, Cecil Moore
wrote:

Estimate the number of hours out of that 12 hours
that you would be transmitting. Multiply that by
the current consumption during transmit. Multiply
the rest of the hours by the current consumption
during receive. Add them together to get an
estimate of the necessary ampere*hour rating
for the gel cell. Be sure to take into account
the minimum operating voltage required by the
hand-held.

I just got through trying to get discharge curves for my station's 12V
Group 27 AGM batteries (for those not familiar with "group" ratings,
this is the size of the battery normally found in compact or larger
automobiles). The manufacturer is Trojan Batteries, a very reputable
battery manufacturer.

What I needed was discharge curves for the battery down to 11.5V which
I have found (the hard way) is the minimum voltage below which most of
my electronic equipment starts going flaky.

From the data that they supplied, for a discharge down to 11.5 V the
AH capacity of a battery is to be derated to 68% of the "industry
standard" 10.5V AH rating.
--

73 de K2ASP - Phil Kane

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

e-mail: k2asp [at] arrl [dot] net