Is the term battery reserve capacity unfamiliar, as we usually hear about battery capacity. Could they be one meaning? But actually, they are hardly connected. Battery reserve capacity is a key characteristic of a battery’s performance. It affects battery life and other battery performance. Below we have organized a series of questions related to battery reserve capacity, let’s explore together!

What is Battery Reserve Capacity?

Battery Reserve Capacity (RC) indicates the amount of time a battery can provide power without being charged. It is the amount of time that a battery can deliver a constant 25A of current before the output voltage drops below 10.5V with a fully charged battery, usually in the range of 100 minutes to 200 minutes. Battery reserve capacity represents the ability to power loads in the event of a power outage or mains failure, especially for cars or boats that require stable power to keep equipment running.

How to measure the battery reserve capacity?

Fill the battery: The meaning of the battery reserve capacity, simply explains that it needs to indicate the power generation time of a full battery in the output current in 25A, output voltage in 10.5V or more. So, filling up the battery is the prerequisite for measuring it.

Connecting a 25A continuous load: The reason for connecting a 25A continuous load is to ensure that the output current of the battery is always at 25A in order to minimize the measurement error.

Voltage monitoring: For monitoring, you can use an oscilloscope or a multimeter to monitor the battery voltage in real time. You can stop monitoring the voltage until the battery drops to 10.5V, but keep an accurate record of the time during this process.

Get the battery reserve capacity: from the beginning of the battery connected to a continuous load of 25A to the voltage drops to 10.5VD the number of minutes is the battery reserve capacity of this battery.

Factors affecting reserve capacity

Temperature: At higher temperatures, the ions inside the battery are more active, resulting in faster chemical reactions, allowing more energy to be stored and thus increasing the battery reserve capacity. At lower temperatures, the opposite is true, resulting in a decrease in reserve capacity.

Self-discharge rate: If the self-discharge rate of the battery is high, the power inside the battery will automatically be released as the loads are powered, resulting in less energy being supplied to the loads. The equivalent is that the battery has enough power, just not all the power to provide the load.

Usage time: Generally, old batteries do not have the reserve capacity of new batteries to be large, because in the process of daily use is inevitable to cause wear and tear of the battery, even though your battery is not worn, but the number of battery charging and discharging cycles is limited, in the process of charging and discharging, the internal materials or electrodes of the battery will be consumed, naturally, the battery reserve capacity will be reduced.

Maintenance: Proper maintenance can help to reduce the consumption of time on the battery, try to keep the battery’s working condition stable, can maintain the battery reserve capacity in the long term.

Battery type: For different battery types, their battery reserve capacity is different. But relatively speaking lithium batteries will have a larger reserve capacity than traditional lead-acid batteries. The reserve capacity of lithium batteries and traditional lead-acid batteries is also related to other battery parameters.

Use mode: we are in the habit of using the battery is to use up the battery’s power completely before charging the battery, which has a great impact on the battery reserve capacity. For lead-acid batteries, it is best to charge the battery between 60% and 80% of the remaining power, this mode of use can slow down the reduction of the reserve capacity of lead-acid batteries. For lithium batteries, it is best to start charging the battery at 30%~40% of the remaining battery capacity in order to stabilize the reserve capacity of lithium batteries.

Importance of battery reserve capacity

The size of battery reserve capacity is of great significance to the use of energy in daily life and the popularization of renewable energy. Battery reserve capacity is not only for cars or boats that need a stable power supply, but also for almost all devices that contain batteries inside. If you know the reserve capacity of your battery, you can utilize the power more efficiently. Whether your battery has a reserve capacity of 100 minutes or 200 minutes makes a big difference, and it can directly change your usage pattern, especially when you are traveling, the battery reserve capacity can reduce the risk of power outages, and help you to effectively organize your travel time.

How to choose the right battery reserve capacity?

Calculate Power Demand: Calculating power demand simply means calculating the total power consumption of your entire power system in a day. If you are using the battery reserve capacity at home, you can calculate the average daily power consumption by continuously watching your meter. If you are using the battery reserve capacity in your vehicle or boat, you can calculate your system’s daily power requirements based on your current battery charge cycle combined with the battery’s depth of discharge.

Consider Usage Patterns: Your choice of battery reserve capacity will also be based on your assessment of how often you want to charge the battery and how long you want to use it so that it can meet your needs. For example, if you intend to limit the battery usage time to 3 hours, it is best to limit the battery to one with a reserve capacity of 3 hours or more to make it easier for you to use.

Consider the load requirements: For the load, the minimum reserve capacity of the battery is 10.5V output voltage and 25A output current, then the load requirements for the input voltage and input current should not be greater than the above data, in order to ensure that the battery can reach the peak demand, and to prevent the load from not operating normally.

Consider the usage environment: Battery reserve capacity is usually measured at 25°C. If your usage environment is under extreme weather or other environments that affect the battery reserve capacity, you need to adjust the size of the battery reserve capacity according to the actual situation.

Conclusion

Every battery has its own reserve capacity, which is not only related to the battery itself, but also affected by many factors during use. When choosing the right battery reserve capacity, you can choose the right battery reserve capacity for you according to the above content.