You Need To Know The Important Parameters Of Lithium Batteries
From outdoor adventures and off-grid RV camping to ocean trolling, solar energy storage and golf carts, lithium batteries are now used in a wide range of applications. In this article, Temgo has compiled the important parameters of lithium batteries for you to help you have a more comprehensive understanding of their important parameter information, which will help you choose the best lithium battery model with reliable performance, high safety and long service life according to your power needs.
What is Lithium Battery Capacity: Providing You with Longer-lasting Power
Battery capacity determines how much power a lithium battery can store, directly affecting how long it can power your devices at full charge. Battery capacity is measured in ampere-hours (Ah) or milliamp-hours (mAh, 1Ah = 1000mAh), depending on the battery's active material. For example, a 10Ah battery discharged at 1A will last about 10 hours.
a. Capacity Type
Rated Capacity: The capacity specified by the manufacturer under standard conditions (e.g., 77°F, a specific discharge rate), as shown on the battery label.
Actual Capacity: Actual capacity will vary depending on discharge rate, temperature, and device demands. The high power draw of a trolling motor may reduce the effective capacity compared to a low-power RV fan.
Theoretical Capacity: The maximum charge possible under ideal conditions, which is rarely achieved due to environmental and operating factors.
b. Run time of different capacities under specific usage conditions
Ah = discharge current (I) × discharge time (T)
For example, a 100Ah battery can last for 1 hour at 100A (100 ÷ 100 = 1). For batteries of different voltages, the energy calculation formula is as follows:
Energy (Wh) = Voltage (V) × Capacity (Ah)
A 12V 100Ah battery can provide 1200Wh (12 × 100) energy. To estimate the run time of the device, divide the energy by the power:
Run time (hours) = Energy (Wh) ÷ Power (W)
For a 500W coffee machine, a 12V 100Ah battery (1200Wh) can theoretically provide 1200 ÷ 500 = 2.4 hours. However, taking into account factors such as 80% DOD (only 80% of capacity is used to extend life) and 90% inverter efficiency (to account for energy losses), the battery runtime can be estimated as:
Usable energy = 1200Wh × 0.8 × 0.9 = 864Wh
Run time = 864 ÷ 500 = 1.73 hours
Some sources claim up to 2.5 hours of runtime, which may be due to specific battery design or partial load assumptions, but for lithium batteries with 80% DOD, the battery runtime is usually 1.7-2 hours.
c. Practical tips
Charging at 1/10 capacity (e.g., 10A for a 100Ah battery) takes about 10-15 hours and extends the battery life. Fast charging (e.g., 0.5C or 50A for a 100Ah battery) is faster but may shorten the battery's cycle life. High current discharge generates heat, so make sure the battery is ventilated, especially in a warm environment. Cold weather (e.g., 32°F) can cause battery capacity to decrease by 10-20%. To maintain battery capacity, store the battery in an environment of 59-77°F and keep it at 70% charge.
d. Practical Applications
RV Off-Grid: A 12V 200Ah battery can power a 100W refrigerator (8.3A) for about 24 hours, which is perfect for weekend camping.
Solar Energy Storage: A 12V 460Ah battery can store 5520Wh of power, which can fully power a 500W solar system for 11 hours.
Marine Trolling: A 100Ah battery (100A) can power a 50-pound-thrust trolling motor for about 1 hour at high speed.
Outdoor Adventures: A 10Ah battery (1A) can charge a smartphone for about 10 hours while hiking.
Golf Cart: A 100Ah battery (150A) can support about 40 minutes of high-intensity driving on a mountain course.
| Application | Capacity Range | Runtime at 100A | Scenario Example |
|---|---|---|---|
| RV Off-Grid | 100-200Ah | 1–2 hours | Runs fridge for 1–2 days |
| Solar Storage | 50–400Ah | 0.5–4 hours | Stores 2 days of solar energy |
| Marine Trolling | 80–150Ah | 0.8–1.5 hours | Powers motor for high-speed bursts |
| Outdoor Gear | 5–20Ah | 3–12 minutes | Charges phone for a week |
| Golf Cart | 50–100Ah | 0.5–1 hour | Drives 18 holes with heavy load |
What Is Lithium Battery Energy Density
Energy density measures the amount of energy stored per unit weight (Wh/kg) or per unit volume (Wh/L) of a battery. The calculation formula is:
Gravimetric energy density (Wh/kg) = Capacity (Ah) × Nominal voltage (e.g., 3.6V) ÷ Weight (kg)
Volumetric energy density (Wh/L) = Capacity (Ah) × Nominal voltage ÷ Volume (cm³)
Most lithium batteries have an energy density of 100-200 Wh/kg, which is suitable for many applications. Golf carts or electric cars usually need energy densities of more than 300 Wh/kg to maximize driving range without increasing volume.
However, batteries with higher energy density are correspondingly more expensive. For example, a 200 Wh/kg battery may cost 20-30% more than a 150 Wh/kg battery, but weigh less.
For a golf cart, a 200 Wh/kg battery could extend the range by 10-15 miles over a 150 Wh/kg pack, allowing for longer driving range or increased payload without adding weight to the vehicle.
| Application | Desired Energy Density | Benefit | Scenario Example |
|---|---|---|---|
| Outdoor Gear | 150–200 Wh/kg | Lightweight, portable power | 5kg pack for a week-long hike |
| Golf Cart | >200 Wh/kg | Extended range, space efficiency | Extra 10 miles per charge |
| RV/Solar Storage | 100–200 Wh/L | Fits tight spaces | Powers RV for 2 days in small bay |
| Marine Trolling | 150–200 Wh/kg | Improved boat handling | Saves 5kg for better maneuverability |
What Is The Nominal Voltage Of Lithium Batteries
The nominal voltage refers to the average voltage that a lithium battery maintains during discharge, which is determined by its chemical composition. It ensures that the operating voltage of the battery matches your device for consistent, reliable performance.
Voltages of different chemical compositions
Ternary lithium: The nominal voltage is 3.6V per cell, and the operating voltage range is 2.5V-4.2V. A 10-cell battery pack in series can provide a voltage of 36V (25V-42V).
Lithium iron phosphate (LiFePO4): The nominal voltage is 3.2V per cell, and the operating voltage range is 2.0V–3.65V. A 15-cell battery pack in series can provide a voltage of 48V (30V–54.75V).
Storage and maintenance
The battery should be stored in an environment with a charge of 70% and cycled at least once every 3-6 months to prevent performance degradation at low voltage (<2.5V), which will compromise chemical stability and shorten service life.
What Is The Lithium Battery Charge And Discharge Termination Voltage: Protect Your Battery
The termination voltage defines the safe limits for charging and discharging lithium batteries to prevent battery damage and ensure safety. Exceeding these limits may shorten battery life or cause dangers such as overheating or battery swelling.
Critical voltages
Charge termination voltage: Maximum charging voltage (4.2V for ternary lithium batteries and 3.65V for lithium iron phosphate batteries). Overcharging may cause battery performance degradation or safety issues.
Discharge termination voltage: Minimum safe voltage (2.5V-3.0V for ternary lithium batteries and 2.0V for lithium iron phosphate batteries). Discharging below this voltage may cause permanent capacity reduction.
Safety and troubleshooting
A battery management system (BMS) is used to enforce these limits, but its functionality needs to be verified by checking the voltage cutoff during charging.
Common mistakes include using an incompatible charger (for example, using a 4.5V charger for a 4.2V ternary battery), which can cause overcharging and cause the battery to swell or heat up.
Watch for warning signs of overheating, reduced battery life, or physical swelling, and stop using the battery immediately if you notice any abnormalities. If the battery loses power prematurely, check for loose connections or recalibrate the BMS by fully charging it.
Useful Tips
a. Verify that the charger voltage setting matches the battery chemistry (fox example3.65V for lithium iron phosphate).
b. Avoid deep discharge in cold weather, as this can increase battery damage.
c. Use a multimeter to test the charger to ensure it meets the end voltage, especially in an off-grid setting.
What Is The Charge And Discharge Rate Of Lithium Batteries: Power Output Speed
The charge and discharge rate is measured in C-rate (current ÷ rated capacity), which determines how fast a lithium battery can be charged or discharged. For a 24Ah battery, 48A discharge is 2C (0.5 hours), while 12A charge is 0.5C (2 hours).
Understanding C-rates
High C-rates (1C-10C): deliver high power, but effective capacity is reduced due to internal losses. For example, a 100Ah battery at 2C can deliver 200A for 30 minutes.
Low C-rates (0.1C-0.5C): maximize efficiency and lifespan, ideal for slow charging in solar systems.
Things to note
High C-rates generate heat, so in high-power applications (such as trolling motors), ensure adequate ventilation. 0.2C-0.5C charging will extend the life of the battery, but charging time is longer, so please plan your charging time accordingly. Please check the manufacturer specifications before purchase to understand the maximum safe rate to avoid damage. For example, if a battery with a 2C rated current is discharged at a rate exceeding the 5C limit, it may cause the battery to overheat.
What is Lithium Battery State of Charge (SOC): Monitor Your Power Reserves
State of Charge (SOC) measures the remaining capacity of a lithium battery as a percentage (0% = fully discharged, 100% = fully charged). Battery Management Systems (BMS) track SOC using methods such as amp-hour tracking or voltage estimation to ensure accurate power management.
Importance of SOC
SOC helps plan usage and prevent unexpected power outages. For example, a 100Ah battery at 50% SOC has 50Ah remaining. It is common for deep-cycle batteries like LiFePO4 to run at 80% depth of discharge (using 80% of capacity) to balance performance and life. A reliable BMS prevents over-discharge, which is critical to battery health.
Monitoring Tools and Calibration
Tools: Use a Bluetooth app like Temgo or a voltmeter to get real-time SOC readings. Many lithium batteries today have built-in displays for ease of use (e.g., Temgo 12V 100Ah Lithium Battery With LCD Screen).
Calibration: Fully charge the battery every 3 months to reset the SOC reading and ensure accuracy. Partial charges can cause estimates to drift over time.
Troubleshooting: If the SOC appears inaccurate (e.g., shows 50% but cuts off early), check for loose connections, recalibrate the BMS, or consult the manual. Persistent problems may indicate a faulty battery cell.
What is Lithium Battery Internal Resistance: Ensure Efficient Power Delivery
Internal resistance, measured in milliohms (mΩ), is the resistance to current flow inside a lithium battery and consists of both ohmic (electrodes, electrolyte, separator) and polarization (electrochemical reaction) components. Typical 18650 battery internal resistance is 12-15 mΩ, and values above 50 mΩ indicate performance issues.
Impact of Internal Resistance
High internal resistance causes energy loss, heat generation, and shortens battery life, especially under high drain conditions. Under high load, a 15 mΩ battery can deliver power more efficiently than a 50 mΩ battery. Excessive heat generated by high internal resistance can lead to thermal runaway in extreme cases, so low internal resistance is critical.
Practical Tips
For high-performance applications, choose batteries with low internal resistance (<20mΩ). In warm environments (such as a summer boat ride), ensure that the battery is cooled to mitigate heat. If internal resistance is high, avoid fast charging as this can exacerbate battery overheating. Check the resistance periodically via BMS diagnostics as it increases with age.
What is Lithium Battery Self-Discharge Rate: Retention of Charge When Idle
Self-discharge rate measures the capacity loss of a lithium battery when idle, typically 5%-8% per month at room temperature. Capacity loss can be reversible (recoverable with a charge) or irreversible, affected by manufacturing quality, materials, and storage conditions.
Managing Self-Discharge
Store batteries at 59-77°F and 70% capacity to minimize self-discharge. Top up every 3-6 months to prevent deep discharge, which can harm battery performance at low SOC. High-quality batteries (such as premium Lifepo4) typically have lower discharge rates (<5% per month).
Practical Applications
RVs and Boats: A 100Ah battery with a 5% self-discharge rate will still hold 95Ah after a month, perfect for spring camping or boating.
Outdoor Adventures: A 10Ah battery with a low self-discharge rate can power a GPS even after weeks of storage.
Solar Storage: Minimal self-discharge maintains the charge of a 200Ah battery even at low solar input.
Golf Carts: Low self-discharge allows a 50Ah battery to maintain its charge during winter storage.
How To Maintain The Consistency Of Lithium Battery Pack
Pack consistency ensures uniform performance of all cells in the pack, including voltage, capacity, and internal resistance. Manufacturing variations or uneven usage (such as vibrations in a golf cart) can cause inconsistent battery performance, leading to premature cell failure and shortened pack life. Therefore, purchasing a battery management system (BMS) with balancing capabilities can mitigate this by equalizing cell performance.
BMS Features and Maintenance
Active vs. Passive Balancing: Active balancing redistributes power faster and is ideal for high-power offshore trolling, while passive balancing is slower but cost-effective for solar energy storage.
Temperature Monitoring: Advanced BMS units track cell temperature to prevent overheating in hot climates or high-power situations.
Maintenance: Check cell voltages monthly via BMS diagnostics, voltage differences > 0.1V indicate imbalance. In golf carts or marine equipment, batteries should be secured to prevent damage caused by vibration, which can exacerbate inconsistent battery performance.
Practical Tips
Choose batteries from reputable manufacturers with strict quality control to minimize initial inconsistencies. Monitor the health of the battery pack through the BMS app or display and replace faulty batteries in a timely manner. For harsh application environments, use anti-vibration battery holders to protect the batteries from environmental stress.
Conclusion
Knowing the key parameters of lithium batteries above can help you choose the right battery to meet your outdoor adventure, RV camping, sea trolling, solar energy storage or golf cart needs. By combining these parameters with your specific needs, you can ensure reliable power, efficiency and durability in any environment.
