On my first solar powered (SLA charger in order to measure the battery ... I took a measurement of the battery voltage and then I shut down the charger for 5 seconds and made a second measurement... This was done every time I used the device which drew about 100 mA for 100 mS. Doing this provided a charge method that got 3 years use from a Yuasa NP1.2-12 battery as I could tailor the charge to the battery. While I understand the MMPT method... it was done for another reason. The design used (Not my choice) amorphous silicon solar panels. The sputtered silicon type. They as a class have a different life cycle than the preferred crystalline type... they loose efficiency as they are exposed to the sun and can loose as much (the ones I was forced to use) as 30% of their capacity. Today there are solar panels in production that do "wear" out over time. It's easy to tell them apart... they are an amorphous brown color not the pretty blue/purple color of crystalline type... Nor do they look like crystals. This was done before there were efficient one package, inexpensive buck/boost mode switchers that could be processor controlled...
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