How long does it take to fully charge the battery?

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Update time : 2025-11-19

Detailed Explanation of Battery Full Charging Time

Theoretical Calculation Formula

Charging time ≈ Battery capacity (Ah) ÷ Charger output current (A) × 1.1~1.2 (efficiency factor)

Efficiency factor: 1.1~1.2 is used to compensate for energy loss during charging.
Practical application: For a 48V12Ah lead-acid battery (common output current 2A), charging time ≈ 12 ÷ 2 × 1.2 ≈ 7.2 hours.

Charging Time Comparison by Battery Type

Battery Type	Charging Time Range	Typical Charging Time
Lead-acid battery	6-10 hours	8-10 hours (full discharge)
Lithium-ion battery	2-6 hours	3-5 hours (full discharge)

Key Factors Affecting Charging Time

1. Battery Capacity and Charging Current

Larger capacity leads to longer charging time (a 48V20Ah battery takes about 2 hours more than a 48V12Ah one).
Higher current results in shorter charging time (ordinary chargers with 3-5A take 6-8 hours, while fast chargers with 5-8A only take 3-5 hours).

2. Differences Between Battery Types

Lead-acid battery: Slow chemical reaction and low charging efficiency, usually requiring 6-10 hours.
Lithium-ion battery: High energy density (150-250 Wh/kg, compared to only 30-50 Wh/kg for lead-acid), fast charging speed, supporting 2-3 hour fast charging.

3. Remaining Battery Level

From 0% to 100%: About 8-10 hours for lead-acid batteries, 3-5 hours for lithium-ion batteries.
From 30% to 100%: Approximately 60-70% of the full charging time (e.g., about 4-5 hours for lead-acid batteries).

4. Impact of Ambient Temperature

Summer (25℃+): Charging time shortens, 6-8 hours for lead-acid batteries and 2-3 hours for lithium-ion batteries.
Winter (below 0℃): Charging time extends, 8-10 hours for lead-acid batteries and 4-6 hours for lithium-ion batteries.
- Principle: Low temperature reduces battery activity, and the charging efficiency of lead-acid batteries drops to 60-70% of normal temperature at 0℃.

5. Charging Phase Characteristics

Constant current phase (0-80%): Fast charging with stable current.
Constant voltage/trickle phase (80-100%): Charging slows down to protect the battery, taking about 1-2 hours.

Practical Charging Time Reference Table

Battery Specification	Charger Current	Theoretical Time	Actual Time (Summer)	Actual Time (Winter)
48V12Ah	2A	7.2h	6-7h	7-8h
48V20Ah	3A	8h	7-8h	8-10h
60V20Ah	4A	6h	5-6h	6-7h
72V32Ah	5A	7.6h	6-7h	7-9h
Lithium-ion battery (General)	3-5A	3-5h	2-4h	4-6h

Charging Recommendations

1. Lead-acid Battery

Float charge for 1 hour (summer) to 2 hours (winter) after full charge, with a total time not exceeding 10 hours.
Avoid over-discharging; it is recommended to start charging when the remaining power is about 30%, and charge for 6-8 hours.

2. Lithium-ion Battery

Unplug immediately after full charge, or float charge for only 30-40 minutes, with a total time not exceeding 6-8 hours.
Avoid overcharging and over-discharging, which helps extend battery life (up to 1800 cycles, about 8 years).

Summary

Battery full charging time ≈ Battery capacity ÷ Charging current × 1.2 (efficiency factor). The actual time is affected by factors such as battery type, temperature, and remaining power. Lead-acid batteries usually take 6-10 hours, and lithium-ion batteries take 2-6 hours. It is recommended to adjust the charging duration according to the season: no more than 8 hours in summer and 10 hours in winter. Unplug in time or float charge for a short time after full charge to protect the battery life.

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