Not long is the safe answer! All lead acid batteries retain their Ah
rating better if not deeply discharged, those nice "must have" add-ons
for the K2 only serve to make matters worse. My K2 with SSB, DSP, etc.
draws in the region of 360 mA (based on the internal metering) if you
have all options running, even in minimalistic mode it draws a lot more
than the optimistic 150 mA many of us think it draws!
If you believe battery manufacturers advertisements you can in theory
find lead acid batteries that are happy with several hundred cycles to
80% discharge or even more to 50%. Factor in that unless you totally
discharge the battery you won't reach anywhere near 100% of the
theoretical capacity and that discharge will damage the battery. Having
had a West Mountain Radio CBA II battery analyzer for some time, I can
honestly say I have yet to find a lead acid battery that does what it
says on the label and that a second discharge shows a noticeable drop in
Ah rating compared to the first - and that is discharging to a measured
11.5 Volts.
From one well respected manufacturers web site:
1. Shallow discharges will result in a longer battery life
2. 50% (or less) discharges are recommended
3. 80% discharge is the maximum safe discharge
4. Do not fully discharge flooded batteries (80% or more). This will
damage (or kill) the battery. Equivalent to overheating a car’s engine,
extent of damage unknown.
5. Many experts recommend operating batteries only between the 50% to
85% of full charge range. A periodic equalization charge is a must when
using this practice.
6. Do not leave batteries deeply discharged for any length of time.
7. Lead-acid batteries do not develop a memory and need not be fully
discharged before recharging
8. Batteries should be charged after each period of use.
While this was for "deep cycle" wet lead acid cells, do not expect gel
cells to magically be any better.
You can now start to do some arithmetic to look at battery life based on
how many milliamps your K2 is drawing on receive, transmit based on your
likely TX current draw and how often you will be transmitting.
On a positive note, K2 sized gel cells aren't very expensive to replace!
73 Dave, G4AON
K2 #1892 with KBT2 fitted
-------------------------------------
I've been thinking about buying a battery kit for my K2/10. Can
someone that has one tell me how long the battery will last between
charges?
Thanks Scott
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