[Elecraft] KX3 and Solar Panel

Edward R Cole kl7uw at acsalaska.net
Tue May 28 04:01:26 EDT 2013


Lee,

Most solar panel mfrs assume you are charging a battery which holds 
down the voltage or that you are using a solar charge controller 
which regulates the current.

I understand that you wish to leave the "heavy" battery at home.  But 
a small 4 AH 12v gell-cell is not that heavy and will regulate the 
solar panel to an extent.  Under load of a battery the solar panel 
voltage drops.  You do not have a heavy enough load on the solar 
panel when in receive mode in your present set up.

Many large solar panels (60w) will provide up to 22v open circuit, 
but drop down when under load.  To cause a charging current to flow 
into a battery the voltage has to be a few volts higher than the 
resting voltage of the battery.

Another solution is to build a voltage regulator that will hold the 
voltage at 13.8v.  The regulator has to be rated for at least the 
current of your rig in transmit.

73, Ed - KL7UW



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