Jim,
congratulations getting the solar panels to operate closer to their Vmp so they harvest more power when the sun is bright.
Now to add cheap battery protection, could you just put a cheap PWM controller between your new contraption and your battery?
(Sal had actually suggested this months ago on another tangentially related thread about protecting a battery from overcharging). The idea is the PWM controller will get higher current from your homebrew MPPT rig and pass it all through when the battery needs it. But as the battery becomes fully charged, the PWM charger prevents overcharging.
Ed
