[Elecraft] What battery to use?

[Charles Greene]

Mark,

I used the batteries from my boat for field for my K2/100.  They are deep 
discharge marine/RV batteries, one about 60 AH and the other about 80 
AH.  I also use an old car battery in the shack which I keep on float at 
13.8 volts.  Some comments.

The K2 which will work at lower voltages, down to 10.5 volts.  Don't try it 
with some other rigs, which do not work well at the lower voltages.  The AH 
capacity is less at a higher load, so a battery nearly discharged will work 
well on receive, but will not support transmit.  I removed the car battery 
from my car as it wouldn't start it.  I cleaned it up and it has a lot of 
life left as a battery for ham radio use.  Car batteries are designed for 
high starting current and are nrmally kept fully charged by the car 
alternator, as opposed to operating at long periods at partial charge like 
the deep discharge batteries.  Look around for a used car battery, clean it 
up, and it will probably last another few years powering your K2/100.  Just 
keep it floating when you have power available.  Being old, it will self 
discharge faster than a new one, but you won't notice that effect during a 
few hours of operation powering the K2/100.  In the emergency communication 
use, a new deep discharge battery is best.  Keep it floating with a small 
charger or place it in parallel with a 13.8 v low current power supply.  I 
use a 6 amp 13.8 volt power supply in parallel with the old car battery 
with the rig connected directly to the battery.  When the rig wants more 
current on transmitt, it takes it from the battery.  I use a 20 amp fuse 
between the power supply and battery, and have never blown it.  Some 
recommend a low ohm resistor in addition to the fuse.  A 40 watt 115 volt 
light bulb would work.  I just never found it necessary.

GL  73,  Chas, W1CG

At 09:32 AM 7/15/2005, Mark Baugh wrote:
>Hi guys,
>I am gearing up for a portable station for emergency
>communications and have decided to use my K2/100 and
>KAT100 combo.  I want to be able to power it with
>batteries, if the need arises.  Have any of you "high
>tech" Elecrafters used a battery to power a K2/100?  I
>don't know whether to chose a deep-discharge marine,
>an SLA/gel cell or AGM battery.  Let's not beat this
>horse to death, but I would like some help on what the
>best choice would be.  I've been thinking about using
>something on the order of a 50-60 Ahr size.
>
>73,
>Mark Baugh
>W5EZY
>Grenada MS
>
>
>
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