Drop in Battery Level (from 15% to 1%)

Recently I bought a Meizu M2 mini and from the first day I have a small problem with the battery. When the battery reaches 15% suddenly within a minute drops to 1%.Battery Percentage Drop Very Fast for meizu M2 rom (4.5.4 I) When it reach
below 15% the battery drop very fast and automatically switch off the phone. I must suppose this is a software bug, because it’s not a normal behaviour at all, and hope Meizu sorts it out in the next realease. help me. I’m so tired

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