[Elecraft] Battery Power - safety consideerations

[Don Wilhelm]

Dale,

You are correct that batteries provide a good stable source of power.  Just
remember that they can pack a lot of current, and they do not protect
against a short circuit condition like a power supply will - if the battery
terminals are shorted they can provide enough current to melt wrenches,
screwdrivers, etc and spew molten metal a considerable distance.  Be careful
with rings, watches, other jewelery and tools around batteries.

The only other thing that I can think of is that you did not mention venting
the battery to outside air.
Since Lead Acid batteries outgas hydrogen, it becomes an explosion hazard
should it collect in sufficient quantity.  Your 'under the bench location
makes it even more of a problem because the air flow there is likely
limited.

Battery enclosures are available that vent the battery with a tube.  They
used to be available in RV supply centers, but I have not checked in several
years.

73,
Don W3FPR

> -----Original Message-----

>     The ongoing discussions regarding woes involving AC power
> supplies puzzles me, because I've operated for years from 2-volt
> batteries and wonder why it isn't a more common practice.
>     From QRP rigs to 100-watt transceivers through VHF/UHF
> equipment, all my equipment is powered through a single,
> deep-cycle RV/Marine battery in a safety housing under the bench,
> constantly connected to a "smart" battery charger. I took a
> cheap, plastic toolbox and created inside a buss arrangement with
> fusing to make it easy for neatly and safely connecting all the
> various radio power leads to one location. All of this can be
> done for less than $150.
>     In practice, the 20-amp charger absorbs most of the load when
> a 100-watt rig is keyed and the battery simply acts like a big
> capacitor to stop "hash" and voltage flunctuations. When working
> with simple QRP rigs, the pure DC supply is a joy because it
> eliminates the most obvious noise source from getting into the
> receivers. Because the charger is quietly maintaining the battery
> at a trickle rate, there is little gas given off by the battery
> and normal household air movement is sufficient to safely
> eliminate any buildup. The battery box and charger sit under the
> operating desk, where I can keep an eye on voltages, charging
> rates and battery condition.
>     I've operated this way for years without a problem, and have
> had batteries last seemingly forever. I replaced the last one
> after 10 years of use, which included some major tasks at annual
> Field Day events. If there are drawbacks to this type of power
> useage, I'm not aware of them, and highly recommend batteries as
> the least expensive and most stable way to feed all your 12-volt
> equipment. Needless to say, the isolation from wavering AC mains
> is a plus, along with having instantaneous emergency power when
> the mains fail.
>     If there's something I'm overlooking in this type of
> operation anyone would like to address, I'd welcome the comments.
>     73, Dale
>     K6PJV, Sacramento, CA.
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