On Fri, 17 Jan 2003, Roman Black wrote:

*>This called MPPT (max power point tracking) and
*>there are a lot of commercial solar controllers
*>now doing this. I haven't seen a PIC one (yet!)
*>but it has been discussed on the list a few times.
*>All it requires is a PIC to sense current into
*>the battery, and adjust the buck PWM up and down
*>around the MPPT point so max current is fed into
*>the battery for any light level at the solar panel.

I think that MPPT implementation with a PIC is non-trivial. Analog works
best but I haven't made one yet so this is a guess. There must be chips
that do it though. MPPT also applies to generator charging (when the
generator is small and unregulated in speed - like wind generators).
Basically you can't do MPPT without chopping both the input and the output
afaik (to measure Ri of the generator and of the battery, which both
change all the time).

Peter

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