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. Enter The Cap Capacity And Exit The Setting Interface. After The Battery Is Fully , Press And Hold The + Button On The Capacity Display Interface To Reach Full Capacity. If The Effective Capacity Of The Battery Is Unknown, Follow The Steps Below To Detect It. Enter The Setting Interface And Set The Cap Capacity Value To A Large Value, Much Larger Than Your Battery Capacity (For Example, If Your Estimated Battery Capacity Is 20ah, You Can Set It To 30ah) Empty The Battery Pack And Set The Meter Capacity To Zero (Press And Hold The - Key On The Capacity Display Interface), And Then Charge The Battery Pack. After It Is Fully , The Displayed Capacity Value Is Set To The Cap Effective Capacity Value Of The Battery Meter. Description: 1. Battery Terminal Or Charging Terminal Voltage Range: 6-60v Dc. If It Is Higher Than 50v, The Temperature Rise Of The Board Will Be Relatively Large. If It Is Lower Than 6v, The Measurement Will Be Inaccurate. 2. Maximum Allowed Current: 30A. Above 25A, The Temperature Rise Of The Board Is Relatively Large. 3. Voltage Display Accuracy: Resolution 0.02V, Accuracy 0.2V. The Voltage Shows The Voltage Across The Battery. 4. Current Display Accuracy: Resolution 0.02A, Accuracy +0.1A; The Current Displays The Discharge Or Charging Current Of The Battery Main Line 5. Tips: The Product Uses The Hall Principle To Detect Current. It Is Recommended To Stay At Least 15 Centimeters Away From Magnetic Objects When Using It, Otherwise The Current Accuracy Will Be Affected. Note: Different Batches May Have Differences In Product Appearance, Color, And Printed Characters, Which Will Not Affect The Use Size: About 61 x 23 x 58mm Material: plastic colour: As Shown Package Contents: 1 x Coulomb Counter Module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.