Comparison of Range between 36V20AH and 48V20AH Electric Bicycle Batteries
2025-05-21
1、 Theoretical endurance calculation
The core indicator of range is the energy stored in the battery (watt hours, Wh), calculated as follows:
Energy (Wh)=Voltage (V) × Capacity (Ah)
- 36V20Ah battery: 36V × 20Ah= 720Wh
- 48V20Ah battery: 48V × 20Ah= 960Wh
Theoretical endurance difference:
48V battery has higher energy than 36V battery; 33.3%, under identical usage conditions (such as motor efficiency, vehicle weight, road conditions, etc.), the 48V20Ah battery has a longer range, with a theoretical difference of about 33%.
2、 Factors affecting actual battery life
The actual battery life is affected by multiple variables, and the advantages of 48V batteries may be further amplified or reduced:
- Motor Efficiency
- 48V system: usually matched with higher power motors (such as 500W-1000W), with higher efficiency during high-speed cruising (about 85% -90%).
- 36V system: The motor power is relatively low (such as 250W-350W), and the efficiency is similar at low speeds, but the energy consumption increases significantly at high speeds.
- Controller loss
- 48V controller: using more advanced MOSFET or IGBT chips, with lower energy conversion losses (about 5% -8%).
- 36V controller: Traditional chips have high losses (about 10% -12%).
- Vehicle weight and wind resistance
- If the vehicle is designed for 48V (such as an electric motorcycle), the frame is heavier and the wind resistance is greater, which may partially offset the energy advantage.
- 36V models (such as folding cars) are lightweight and have low wind resistance, and the actual range difference may be less than the theoretical value.
- Cycling habits
- Frequent rapid acceleration: The 48V battery has strong instantaneous discharge ability, but high current discharge will shorten the battery life (about 5% -10% loss).
- Constant speed cruising: The 48V system has a more significant energy efficiency advantage.
3、 Scenario based endurance comparison
| scene | 36V20Ah battery life | 48V20Ah battery life | gap |
| Flat road surface with a constant speed of 25km/h | 45-55km | 60-70km | +33% |
| Load capacity 50kg, climbing 10 ° | 30-35km | 40-45km | +33% |
| Low temperature environment (0 ℃, range attenuation of 30%) | 31-38km | 42-49km | +35% |
| High speed cycling (35km/h) | 35-40km | 45-50km | +28% |
Note: The data is based on typical urban road conditions, assuming a motor efficiency of 80%, a vehicle weight of 50kg, and a drag coefficient of 0.5.
4、 Purchase suggestions
- Priority should be given to selecting 48V20Ah
- Need to deal with steep slopes, long-distance cycling, or heavy loads.
- Pursuing fast charging (some models support 3-4 hours to fully charge).
- The vehicle has sufficient reserved battery compartment space.
- Priority should be given to selecting 36V20Ah
- Limited budget or frequent transportation of vehicles may be required.
- The driving route is flat, with a one-way distance of less than 15km.
- The vehicle is a foldable model with limited space.
5、 Technical Extension: The Influence of Voltage on the System
- Controller cost: The 48V controller requires higher voltage resistant components (such as 60V MOS transistors), which is about 20% more expensive.
- Charging efficiency: The 48V battery supports a larger charging current (such as 5A fast charging), and the charging time is shortened to 4 hours (6 hours for 36V).
- Life difference: 48V batteries can extend their cycle life by 10% -15% due to lower discharge depth (under the same range).
At the same capacity (20Ah), 48V lithium batteries have longer battery life, and their advantages have been verified in both theoretical and practical scenarios.
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