Sealed Lead Acid Batteries: Care and Feeding
The sealed lead acid battery ("
EmComm operators, especially for long term and remote field
operations. The larger batteries remain portable and will
support 100 watt HF and both VHF/UHF radios and amps in emergency
or field based situations.
FINDING FREE BATTERIES:
sources, including for little or no charge. When batteries are
removed from UPS systems at hospitals, universities and
government offices, it is often because of time in service rules,
and the batteries are in perfect working order. Several Valley
Radio Club members are able, from time to time, to provide such
batteries to VRC club members involved in EmComm activities. And
you might check for such batteries on your own.
PURCHASING BATTERIES: In addition,
the
available new at reasonable costs. Mouser has a number of pages
on batters at its website, http://www.mouser.com. A Google search will
also turn up web pages on other manufacturers or vendors,
including Power Sonic, which is the battery of choice of Elecraft
for its
SIZING THE
demands of your radio and remote set up, by checking out the
radio manuals, figuring out your equipment demands for 10 to 12
hours, and adding a 10-15% fudge factor. The minimum size for
QRP radios is probable a 12 volt with 2.5 to 3 amp hour ratings;
a much bigger one will be needed for 100 watt stations and/or a
station that will be field operated for multiple days. The
latter will need to be about 20 amp hours.
Note: the ratings are on the batteries, like 7 aH - meaning
theoretically putting out 1 amp for 7 hours. In practice, it
will taper off much faster and you should size your battery at 2
times or 3 times your power needs over 10-12 hours.
WHEN AND HOW TO CHARGE: However you obtain, your
EmComm use, there are some very important do's and don't's about
charging and maintaining your battery. The general rule is to
limit fast or bulk charging to no more than 10% of the batteries
am hour rating. For example, a 7 aH
at no more than a .7 amps level, and given the size of most
charges, at no more than .5 amps.
There is a nice chart on various types of batteries, the how and
when to charge, at http://www.batteryuniversity.com/partone-23.htm. It
is a good idea to print out that chart and even put it in a
plastic sheet protector. You will refer to it often. Another
web source is http://www.uuhome.de/william.darden. While on a German
site, it is in English, and updated often. More science here
than in other quick charts.
COMMERCIAL
charger is at A&A Engineering, which has an excellent little 1
amp charger, with an optional switch to cut it back to a 1/2 amp
level. They also have much bigger chargers as well. This is
called the "Smart Charger" because it has a micro-processor that
tests the battery as it charges, changing the charging from bulk
to maintenance, as the battery responds. It is in both kit and
pre-made chargers. The web site is http://www.a-aengineering.com and is
a ham radio owned company in
CONNECTION STANDARDS: The standard connection system used by
ARES is the Anderson Power Pole. You can find ads for power
strips with Power Poles, and some have both banana plug and Power
Pole connectors on the strip, in QST and CQ Magazine. Two good
sources are from West Mountain Radio [they call theirs the "Rig
Runner"] at http://www.westmountainradio.com and from MFJ Enterprises at
http://www.mfjenterprises.com. West Mountain Radio also sells pre-made
Power Pole harnesses, separate Power Poles and tools for easy
crimping. Another source is Power Werx, whose website is
In summary, to be able to operate a HF station or VHF plus amp,
for any time off of commercial power, you will need the
appropriate sized sealed acid battery, properly charged and
maintained. These tips should help you "be prepared."