[Elecraft] K2 Battery Life?

Thu Dec 4 18:05:00 2003

Various float voltages are quoted but I have found them to be =
inaccurate. The rule of thumb is to use a float voltage that will cause =
a float charging current of C/500. Since the float voltage is =
temperature dependent, I wonder if a constant current should be used for =
float. For a 3AH battery one would set it to 6mA. An 18V power supply =
and a 680 ohm resistor would do the job. Would this be better than =
occasional topping off? I hate to be a slave to my batteries.

    Dave=20

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Francis Belliveau
Sent: Thursday, December 04, 2003 3:30 PM
To: [email protected]
Subject: Re: [Elecraft] K2 Battery Life?

Both overcharging and deep cycling have similar effects on SLA battery =
life.
What most people do not realize that when the open circuit voltage drops =
to
10.5 volts the battery is deeply discharged.  Using a cutoff voltage of =
11.5
volts is much better and will likely not harm the battery very much.

I have heard too many who believe that deep cycling is zero volts.  That =
is
absolute death to an SLA battery.

The other thing that must be watched is the "shelf" discharge.  If you =
do
not use the battery much, keep an eye on the voltage and recharge it =
when it
drops to 12 volts.  This will keep it in good shape and extend it life =
if
not overcharged.

73,
Fran

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