[Elecraft] re: solar power

[Bob Lewis (AA4PB)]

> Look at the heat sink on this controller!

This is a shunt mode controller. During the times that the charge is
not needed by the battery, the power generated by the solar panel is
dissipated as heat in the controller. This does not really equate to
wasted power because that power is not needed by the battery during
the time it is being dissipated anyway and its essentially free from
the sun. The biggest problem is simply getting rid of the heat.

Series mode controllers "open" the circuit to the battery when
charging is not needed therefore the series mode controllers don't
generate so much heat. The problem with series mode controllers is
that many designs require some sort of switching regulator to generate
the higher voltages needed for the control circuit and this can
generate RFI. Take a look at http://www.seslogic.com/microm+.html for
a series mode charge controller that does not use a switching circuit
and so does not generate RFI.