While the Ryobi battery 40V is known for reliability, a few common issues can frustrate users. One frequent problem is the battery not charging, often due to dirty or corroded terminals—cleaning them usually fixes it. Another is reduced runtime, which can happen if the battery is stored in extreme temperatures. Some users experience sudden power loss, often caused by an unbalanced cell, which may require a few full charge cycles to recalibrate. If your battery flashes error lights, consult the manual for the specific code. Overcharging is rare, but avoid leaving it on the charger for days. For best results, keep the battery between 20% and 80% charge during long-term storage. Many switching from DeWalt 18V battery replacement units notice that lithium-ion batteries are more sensitive to care habits. Dropping the battery can cause internal damage, so handle it with care. Using the correct Ryobi charger also prevents voltage mismatch issues. With the right maintenance, your 40V battery can deliver consistent performance for years.