IoT hardware engineer Jasper Sikken designed his AEMLION Solar Powered Li-Ion Charger for his entry in the Hackaday Prize 2018 (Power Harvesting Challenge), and is now available for purchase on his Tindie page and Amazon as well. The board is outfitted with an E-peas’ AEM10941 photovoltaic solar harvesting IC, capable of extracting DC power from up to seven different solar panels and can store the energy while also supplying a system with two independent voltages.
The AEMLION works with both outdoor and indoor lighting, and offers 3.3V and 1.8V regulated outputs, which are enabled when the battery has enough charge. Additionally, it features a low-charge warning when the battery is near depleted, and the system is about to shut down.
According to Jasper, the AEMLION has an ultra-low power startup with the boost converter starting at a very low 380mV input voltage and 3uW input power. The IC also gets the most power it can grab out of whatever solar cell/s you integrate by implementing maximum power point tracking (MPPT) every 5-seconds. As far as the specs are concerned, the AEMLION has a solar input voltage of 50mV to 5V, a solar input current of 110mA, 3.3V/80mA and 1.8V/20mA regulated outputs, reverse voltage protection, and a 3.3V status output pin that warns the host MCU if the power drops below 3.60V.
Interesting enough, Jasper designed another version of the solar charger, dubbed the AEMSUCA, which uses a pair of supercapacitors to store that harvested solar energy rather than relying on a battery. Other than the storage medium, both boards appear to be identical with the same spec set and the same price-point, $24.90, which gets you either solar harvester and a pair of 5-pin male headers.