Advanced energy storage technologies are essential building blocks for a renewable energy future. Battery management is crucial to the delivery of reliable, cost-effective off-grid power, as batteries can be very easily damaged even during normal operation, thereby reducing their lifespan and the effectiveness of the power system. That is why knowing a battery’s capacity and its precise state of charge are crucial features in protecting the health of a battery and extending the life of a mission-critical off-grid power system. However, when it comes to batteries designed to support heavy loads such as telecommunications applications, calculating the state of charge is complicated by many practical and theoretical obstacles. Still, it can have major benefits for the overall power system’s cost, longevity and reliability. So why is it essential for off-grid power? Let’s find out.