See
http://electronicdesign.com/site-fi...ctronicdesign.com/files/29/6262/figure_01.gif
for circuit and:

http://electronicdesign.com/energy/maximum-power-point-tracking-solar-battery-charger
for article.

Never tried it myself.

 

Never thought about that.
...

I did a commercial Solar MPPT years ago (around 2003?) and that was the core of the microcontroller algorithm; keep the panel volts at X and some small tweaking of that voltage. Much better efficiency and more constant current into the battery than a fully blown P&O.

It can require an initial tweak for the panel type; amorphous or monocrystalline types etc as they have slightly different MPP voltages.