Solar PV regulators/controlers

Yes, Figures 8 and 9. Note, SEPIC and SuperBuck both feature nearly constant input current. They liked the SEPIC buck-boost aspect, its extra series capacitor, and its micro-satellite track record.

I've since examined a few dozen SuperBuck papers, a nice 4th-order follow-on to the classic optimum Cuk converter. Good literature in the advanced power-supply-engineering community, not much in the switcher IC app-note community.

Using either a SEPIC or SuperBuck solar-panel converter gives one a much more sensible MPPT world to work in.

What works even better than PV module optimizers is a chain-saw.

Nip the problem right at the obstruction

I am currently thinking of a flyback converter with a step-down transformer . That would transfer pulses on energy to the output. The output voltage would be defined by the battery, and energy limited by the feedback circuit . On another part of the system, the charge strategy, can anyone comment o n this energy transfer as opposed to the CC, then CV charging. I believe ( I may be wrong) that an over discharged (wet cell) battery needs lower curr ent, maybe 0.05 - 0.1C charging until it gets to the start of the bulk char ge range, then 0.2 - 0.3C during bulk charge, then a rolloff rather than cu t-off to float charge. Temperature sensing being assumed.

A discharged battery takes whatever it needs in current. Below the Absorb or float voltage, unless it has had Absorb charge recently IS in bulk charge.

You just current limit if you have an abundance of power available but limit the voltage to either Absorb or Float (or EQ) voltage.

Buck converters are typically used for charging LA batteries unless it is a PWM type controller... If PWM type, it's just a switch to keep direct connection from PV to battery in Bulk and PWMing when the voltage gets to Absorb, bulk or EQ voltage to keep it voltage regulated at that stage.

There's an interesting tradeoff....

Cut down trees so the solar panel can work. m