Khethworks, a startup that emerged from MIT Tata Center in 2015, provides affordable, reliable solar-powered irrigation solutions to smallholder farmers in India.

While the mechanical properties of their system are known in detail, a study of its electrical properties has not been conducted. This research aims to optimize daily amount of water delivered by the pump, given a certain solar panel sizing, and prevent unnecessary battery degradation.

We compare the performance of two possible solar-panel interfaces – Maximum Power Point Tracking (MPPT) and Direct Load Line (DLL). Result from system-level simulation suggests that the MPPT approach is more efficient over a range of solar panel rating, but is only slightly more efficient for the current system size. The simulation raises a concern over battery life. Due to over-charging, over-draining, and irregular charging cycle, the battery might not last as long as expected. Because the battery contributes a significant portion of the system cost, it is of our interest to implement a battery management system.

After completing the simulation, we plan to test prototypes of the MPPT and battery protection circuit. We hope to finish the first run at our MIT laboratory and run an outdoor trial afterward