Fangrui Product Details The Product Uses The Hall Principle To Detect Current. It Is Recommended To Keep At Least 15 Cm Away From Magnetic Objects During Use, Otherwise The Current Accuracy Be Affected. First-time Use Method When Using Or Replacing The Battery For The First Time, You Need To Correctly Set The Actual Effective Capacity Of The Battery (cap Value In The Setting Interface). If The Effective Capacity Of The Battery Is Known, Enter The Setting Interface To Enter The Cap Capacity, And Then Exit The Setting Interface. After The Battery Is Fully , And Hold The + Button On The Capacity Display Interface To Set The Full Capacity. If The Effective Capacity Of The Battery Is Unknown, You Need To Follow The Steps Below To Enter The Setting Interface And Set The Cap Capacity Value To A Large Value, Much Larger Than Your Battery Capacity (for Example, What Is Your Estimated Battery Capacity The Capacity Is 20ah, Which Can Be Set To 30ah) . Drain The Battery Pack And Set The Meter Capacity To Zero ( And Hold The - Key On The C