[Elecraft] Good Battery for K3 Portable Ops

[Bob]

I ran my club's FD GOTA station off battery/solar power this year.  The
GOTA station was in heavy use for about half the 24 hour period, and
lighter use for the rest.

Over that contest and several others, I've developed the following
guidelines for my K3:

1) Casual operation is about 2 AH per hour (a few Qs an hour)
2) GOTA operation is about 3 AH per hour (a dozen Qs an hour)
3) Full run mode high Q rate (200 Qs an hour), takes 9.5 AH per hour

LiFePO4 batteries are great for this purpose and available in many sizes.
 Higher voltage, more usable power, smaller size and weight are all
improvements over SLA batteries.

I have used a 10 AH LiFePO4 battery with my K3 for 4 hour periods MANY
times.  We ran a K3 in full contest run mode for a solid hour off the same
battery.

Some brands to consider:  K2 Energy, Tenergy, Bioenno.

They all sell "SLA Drop-in Replacement" batteries that have built-in
battery management electronics that protect from over-charge,
over-discharge, and keep the internal cells balanced. Expect the life to be
at least 5 times that of a SLA, and the weight to be 1/4th (if comparing
identical usable capacity -- you need a 20AH SLA to equal the usable
capacity of a 10AH LiFePO4).  Only thing to watch for is to make sure the
battery management system is compatible with a 20 amp load.

73, Bob, WB4SON