If you have purchased a 100-amp-hour battery, you may be wondering how long it will last. For example, can it help you light your home during a power outage or power your devices while camping? In this article, we provide you with a formula for calculating the maximum runtime of a battery. We will also explain what amp-hours and amp-hour ratings are, as these terms are important when calculating battery runtime.

How to understand 100 amp-hours and 100 mah

100 Amp-hours

The amp-hour rating of a battery is a measure of its capacity to store electrical energy. The "amp" in amp-hour refers to the current, or flow of electrons. The "hour" refers to the time that the battery can provide that current (in hours). For example, if a lithium battery has an 100 amp hours, it can provide 1 amp of current for 100 hours before it is depleted. Or, it can provide 10 amps for 10 hours, or 20 amps for 5 hours. The total current remains at 100 Ah. The higher the amp-hour rating of a battery, the longer it can provide energy. Larger batteries have higher amp-hour ratings. Manufacturers use these ratings to tell buyers how long the battery will last.

Calculating amp-hours is simple. You simply multiply the current (in amps) by the time (in hours).

For example, if a device uses 40 amps of current and you use it for 10 minutes, the device will consume 6.64 amp-hours of power.

You can calculate the amp-hour capacity of a battery (6.64 amp-hours) by multiplying the current (40 amps) by the time (10 minutes).

battery cell
100mah battery

100 Mah

MAh stands for milliamp-hours, which indicates the amount of current that a battery can discharge in one hour. The current capacity of a battery is a unit of measurement for the amount of power and duration that it can provide. The higher the current capacity, the longer the battery can provide energy.

Milliamp-hours (mAh) is the unit of measurement for the current capacity of a battery. 100mAh = 0.01 amp-hours (Ah).

For example, a 100mah battery can provide 0.01 amps of current for 1 hour, or 0.1 amps of current for 10 hours. Smaller batteries, such as TV remotes, flashlights, etc., consume current in the mah range, so they are rated in mAh-hours. Larger batteries are rated in Ah. Smaller batteries are rated in mAh because rating a battery as 0.9 Ah instead of 900 mAh sounds awkward.

how long will a 100 amp hour battery last

Lithium iron phosphate batteries (LiFePO4), also known as lithium iron phosphate batteries, are known for their excellent cycle life. Compared to other lithium-ion battery chemistries, this chemistry has higher stability, safety, and durability. LiFePO4 batteries inverter can provide AC power to household loads through an inverter.Lithium ion battery for inverter output DC power, while inverters output AC power.

To calculate the runtime of a 100Ah LiFePO4 battery, you need to consider a few factors. One key factor is the power consumption of the devices connected to the battery. The more power these devices require, the faster the battery will drain. For example, let's assume the total power consumption of the devices is 600W, and the voltage of the 100Ah LiFePO4 battery is 12V.

Battery runtime calculation

Battery output current = 600W / 12V = 50A

Battery runtime = 100Ah / 50A = 2 hours

Therefore, the battery runtime is 2 hours.

How long can a MicroBat 2.5kWh balcony battery system last when the micro-inverter is outputting? Let's calculate the balcony battery system's runtime together. (According to the law of conservation of energy, energy = power x time, E = P * t)

The maximum output power of a 800W micro-inverter is 600W / 800W. A MicroBat 2.5kWh battery in a fully charged state has a maximum output power of 600W, with a continuous output time of about 4 hours. However, since the total output power of the battery is limited by the input power and output power of the micro-inverter, the total output power of the battery can only output the maximum output power of the micro-inverter. Therefore, the runtime is as follows:

Divide the micro-inverter output power, battery capacity, and time equally:

Peak hour, the micro-inverter's maximum output is 600W, the battery's continuous output is 2 hours, and the maximum output power is 1.2kWh

Power consumption = 600W x 2h = 1.2kWh

Remaining power = 2.5kWh - 1.2kWh = 1.3kWh

The micro-inverter's maximum output is 800W, the battery's continuous output is 2 hours, and the output power is 1.6kWh

Power consumption = 800W x 2h = 1.6kWh

Remaining power = 2.5kWh - 1.6kWh = 900Wh

After the peak hour, the micro-inverter output is set to 400W, and the battery's maximum output power is 400W

When the battery's remaining power is 1300Wh, the available time is as follows:

Remaining time = 1300Wh / 400W = 3.25h

When the battery's remaining power is 900Wh, the available time is as follows:

Remaining time = 900Wh / 400W = 2.25h

It is worth noting that this calculation only provides an approximation, as the actual runtime may vary depending on various factors such as temperature, battery life, and battery condition.By understanding how much power your devices consume and performing these calculations, you can better assess the runtime of 12V 100Ah and 51.2v 50Ah batteries, and plan backup or replacement options accordingly.

How to choose a Lithium ion battery for an inverter?

  • Choosing a lithium battery with the same input voltage as the battery terminals of the inverter can ensure the compatibility of the battery with the inverter, avoiding the safety hazards caused by using incompatible batteries.
  • Configuring the battery capacity according to the customer's backup power requirements can ensure that the battery can meet the customer's usage needs, avoiding the waste caused by insufficient or excessive battery capacity.For example, a customer chooses a 10 kW inverter with a battery voltage input of 48V and needs a 2-hour backup power supply.It is recommended that customers using 48V lithium batteries, the total energy required for 2 hours of backup power is 10 kW x 2 hours = 20 kW (20 kWh). It is recommended that customers recommend 5 48V 100Ah 1C discharge lithium batteries in parallel. The energy that a single battery can provide = battery discharge voltage x battery discharge current = 48V x 100A = 4800 watts, 4800W x 5 = 24000 watts = 24kWh. (It can be configured more appropriately to prevent the battery from being too low, which is beneficial for endurance.)
  • Considering whether the maximum discharge power of the battery matches the power of the inverter can ensure that the inverter can work normally, avoiding thelithium ion battery for inverter overload caused by insufficient battery power.For example, a customer chooses a 10KW inverter and wants to configure a battery with a rated voltage of 51.2V 100AH 1C discharge.The rated voltage of 51.2V 100AH 1C discharge battery is 5120W, and the energy provided cannot make the inverter fully loaded (10KW inverter 10KW is called full load). The battery provides 5120W of power to the inverter, so the inverter cannot run at full load. It is recommended that customers configure at least 2 51.2V 100AH lithium batteries or more lithium batteries to meet the full load running requirements of the inverter.

How is the capacity of a 100 amp-hour AGM battery calculated?

AGM stands for absorbed glass mat. The electrolyte in this type of battery is absorbed into a special sponge made of glass fibers. This advanced technology makes AGM batteries leak-proof, completely sealed, and maintenance-free.

AGM batteries are some of the safest batteries you can find. They have a longer lifespan than standard wet batteries due to less degradation and corrosion inside the battery.

AGM batteries also hold a charge well, with a lower self-discharge rate.

Assuming a 12V 100Ah AGM battery, its capacity is 1200Wh, or 1.2kWh, according to the capacity calculation formula Wh = Ah x V.

Conclusion

In this article, we discussed how to calculate the runtime of a 100Ah lithium battery. We also explained what amp-hours and amp-hour rating are, as these terms are essential for calculating battery runtime. By understanding how much power your devices consume and performing these calculations, you can better assess the runtime of a 100Ah battery and plan backup or replacement options accordingly.

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