Chosen Solution
My macbook battery is stuck on 1%. While using mac, it is very slow. I checked cpu usage, the culprit is kernal_task. Fan speed is also very high. Is Battery failure causing high kernal_task cpu usage? Or is there any other failure in my hardware apart from battery?
This is almost certainly a failed battery. If a MacBook cannot get sensor data from the battery (or any other sensor in the device), it assumes the worst. It throttles the CPU and ramps up the fan to fight the searing temps it assumes whatever component is experiencing, even if the issue is just a sensor has died, or cannot communicate with the SMC/T2. I have seen this issue many times on various Macs. I would run Apple diagnostics (Press and hold D key when you’re powering the unit on from a powered off state) and see if it throws any errors.
