I'm the maker of VBatPower (vbatpower.com) a free, browser-based tool for battery and power engineering. It's built to answer three questions for anyone working on battery-powered electronics: how long will it last, how much power does your circuit draw, and how does it discharge over time.
VBatPower simulates how long your battery lasts, how much power your circuit draws, and how it discharges over time — for IoT, embedded, and portable electronics. 438 verified formulas, 12 converters, units-aware calculator flows, and MCU telemetry. Free in beta.
