Posted by
G3VVT on
Jun 12, 2004; 5:30pm
URL: http://elecraft.85.s1.nabble.com/FW-K1-Battery-Question-tp367714p367715.html
John,
One factor that is being missed out on the calculations is how good is the
battery in question. Most assume that say a 7Ah capacity battery will give that,
but in practice this can often fall short. I've witnessed experienced
installation contractors with skills of loading in the last mAh into large
communication battery plant, sweating to get over the 90% mark to the defined pass
figure for acceptance. They use techniques probably not used by most hams in order
to achieve this and get the acceptance certificates signed off.
So how good is the battery being used today? It may have only 75% of original
capacity left, so better to be on the generous side what the duty cycle may
be and be pleasantly surprised when the estimated battery life is exceeded.
Not too sure if this applies in the USA, but there is a source of 12V 7Ah
sealed batteries available from commercial alarm systems in the UK at least. The
batteries in these systems are trashed at about 3 years after new battery
installation. I guess it must be a lot more cost effective for the maintenance
companies to do this rather than experience costly failures. We have a few
recycled batteries here providing power backup for local repeaters. It pays
dividends to get to know who your local alarm technicians are to tap this source of
batteries for field operations. Should get at least two or three years more life
out of these batteries depending on temperatures experienced during their
usage as high temperatures dramatically shorten their useful life.
Bob, G3VVT
K2 #4168
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