[Elecraft] Battery Charging with DC Power Supply

[WILLIS COOKE]

Be careful.  There is a voltage that is safe for trickle charging a battery, but it is not the same voltage that is optimum for powering a transceiver.  Most if not all transceivers are built for optimum operation at about 13.8 volts which is also the optimum charging voltage for a short term charge of your car battery.  They also work well at 12 volts or a little less so that you can use a car battery when you are not running the engine.  Most of us keep our power supply adjusted to about 13.8V which is a good voltage for battery charging, but not so good for continuous charge.  You will ruin a battery if you keep the voltage that high for long periods.  I don't have the battery specs on hand at the moment but something like 12.3 to 12.5V would be a good continuous voltage.  Also, you have the challenge of connecting at least two large wires to the output terminals of the charger which is difficult on some chargers.  The Astron supply that I have has
 some nice large bolts for connectors, but others have binding posts that are more difficult.

A better solution is to have a separate power supply output for the battery charger and a variable charge circuit to restore the charge after use then reduce the charging voltage for maintenance.  Such a supply is made by JetStream, Model JTPS35BCM and probably others.  I am in the process of installing one in my shack at the moment.  It is reasonably priced and seems a good idea,  I will let you know later how well it works.

Willis 'Cookie' Cooke 
K5EWJ


--- On Mon, 6/8/09, Wes Stewart <n7ws at yahoo.com> wrote:

> From: Wes Stewart <n7ws at yahoo.com>
> Subject: Re: [Elecraft] Battery Charging with DC Power Supply
> To: Elecraft at mailman.qth.net
> Date: Monday, June 8, 2009, 7:40 AM
> Finally, a voice of reason.
>