I. Visual Inspection: Visually Identifying Potential Problems
Bulging or Deformation: Obvious bulging or deformation of the battery casing is a clear sign of internal gas production or mechanical damage. The battery must be stopped immediately and replaced.
Leakage: Check the battery surface for white or transparent crystals, liquid residue, or a pungent odor. This usually indicates electrolyte leakage.
Damage or Corrosion: Cracks or damage to the casing, or severe corrosion of the terminals or posts, will affect connections and safety.
II. Voltage Measurement: Assessing Battery Capacity and Initial Health
Static Voltage (Measured after several hours of rest):
12V Lead-acid Battery (Common in 48V, 60V, and 72V Systems):
Above 12.8V: Fully charged (100%), in good condition.
12.6V - 12.7V: Approximately 75%-100% charged, in good condition.
12.4V - 12.5V: Battery level approximately 50%-75%, acceptable condition.
12.0V - 12.1V: Battery level below 25%, needs to be charged as soon as possible.
Below 12.0V: Severely depleted, battery may be damaged.
Lithium battery (approximately 4.2V per cell when fully charged): Refer to the total voltage of the battery pack (e.g., approximately 13.44V for a 48V system when fully charged).
Starting voltage: The voltage should not be lower than 9.5V (for a 12V battery) at startup. A voltage that is too low indicates high internal resistance and inability to handle the load.
III. Load Test: Verifying the battery's true "sickness-carrying" capability. This is crucial for determining whether the battery is "aging" or experiencing "capacity decay."
Simple load test: Connect a high-power load (e.g., a 12V car light bulb) and observe the voltage change.
Healthy battery: Voltage drops smoothly and remains above 10V.
Aging Battery: A sudden and significant voltage drop (e.g., from 12.6V to below 10V) and dimming lights indicate increased internal resistance and insufficient capacity.
Professional Discharge Test: Use a discharge meter to measure the actual discharged capacity (Ah) and compare it with the nominal capacity. If the capacity degradation exceeds 20%, the battery needs to be replaced.
IV. Charging Performance: Observe for Abnormalities
Abnormally Shortened Charging Time: May indicate decreased battery capacity and inability to store sufficient charge.
Abnormally Longer Charging Time or Incomplete Charging: May indicate internal faults or plate sulfation.
Severe Overheating During Charging: Normal charging will result in slight warmth, but abnormally high temperatures (scalding hot) indicate a problem.
V. Professional Testing: Obtain Precise Data
For the most accurate assessment, professional equipment is recommended:
Internal Resistance Tester: Measures the battery's internal resistance. A significant increase in the value (e.g., exceeding 50% of a new battery's resistance) indicates severe aging.
Battery Capacity Tester: Accurately measures remaining capacity through complete charge-discharge cycles and calculates the state of health (SOH). Battery Analyzer: Performs load tests, startup tests, etc., to comprehensively assess battery status.
Comprehensive Judgment and Action Recommendations
Based on the above test results:
Understanding appearance + Normal voltage + Stable load test + Normal charging: Battery is in good condition and can continue to be used.
Abnormal appearance, excessively low voltage, or sudden voltage drop during load test: Battery is severely aged or damaged; immediate replacement is recommended.
Abnormal charging time or slight overheating: Further load testing or professional inspection is recommended for confirmation.
