Looking for best battery option to run a Xiegu G90 on SSB for a few hours in the field at 10 or 20 watts, making casual QSOs?
“Best” is always a relative term. It can be different
for each person, depending on their personal
preferences and specific needs.
First, what is your picture of “in the field”? Are
you thinking of hauling your station 3 miles up
a mountain? Or parking your car beside a
picnic table in a local park? Operating while
hiking?
There are lots of different versions of “portable
operation”. None of them are “right” or “wrong”,
just different circumstances and conditions. If
you may want to carry your station any significant
distance, then weight and / or size may be very
important criteria. Otherwise they might not be.
What is the current draw of your radio on receive?
At various transmit powers? Are you using a speech
processor? Those all factor into choosing the
required battery capacity for the desired operating
time.
What is the input voltage range where the radio
will operate at the desired power level? That
affects the choice of battery chemistry, as well
as how far down you can run your battery before
the rig stops working.
What is your budget?
Lithium batteries are an excellent choice for small
size and light weight, and they are more expensive.
Not only are the batteries expensive, but they need
a special charger to keep them in good health. They
are capable of high output current, and the voltage
remains high over most of the discharge curve.
Lead gel batteries are heavier, and you may only get
half the rated capacity before the voltage drops
too far (depending on your radio). But sometimes
they can be much cheaper: hospitals and other
commercial installations often swap out the batteries
in their UPSs and other equipment on a regular
basis. I’ve known several hams who pass them
on to others with plenty of life left in them.
Sure, the 40 Ah batteries I often use weigh 23
pounds, so not something I’d want to take
backpacking for a week, but they will run my
K2 for 24 hours on Field Day, and even a 100W
radio for occasional use. And they were free.
A small 5 Ah lead gel battery travelled a lot of
miles in my backpack powering QRP rigs, back
before lithium batteries were available.
In some cases, alkaline or NiMH cells may be
a reasonable choice, especially if you need to
build a battery pack for a particular voltage or
to fit in a specific case. For example, at one
point I standardized on AA batteries for all the
equipment I took backpacking: that allowed
me to swap the batteries between radios, GPS,
and flashlights as circumstances required.
If money is no object, buying a lithium battery
and charging system gives you a lot of options.
If you aren’t sure you are ready to invest that
much yet, there are other options that may
work well enough for you to try it out and see
how you like it.
Meanwhile, our robot vacuum cleaner uses a
14.4 V 2.6 Ah lithium battery. I may see about
borrowing it for radio use on occasions. You
might have something around the house that
can be repurposed temporarily...