The 1200 watt inverter is a common low-power inverter that can convert the 12V DC in the battery into 110V AC. A 1200-watt inverter is like a small power station that can meet your AC needs indoors, outdoors, or on the go. With a rated power of 1200W, you can easily use it to drive laptops, small household appliances, and even some high-power appliances, such as rice cookers, small electric heaters, etc., making your life more convenient and comfortable.
This article will answer in detail the number, type, connection method and influencing factors of batteries required for a 1200-watt inverter. We will discuss power, usage time, battery type and other aspects to help you configure the battery correctly to ensure the best operation of the inverter.
Inverter-rated power and battery capacity
The rated power of the inverter refers to the maximum power that the inverter can output stably for a long time. For a 1200-watt inverter, its rated power is 1200 watts, which means that it can run for a long time with a load power not exceeding 1200W. However, if you want the inverter to run for a long time, you need a battery with sufficient capacity to use with the inverter.
Calculation of battery capacity
The rated power of the inverter refers to the maximum power that the inverter can output stably for a long time. For a 1200-watt inverter, its rated power is 1200 watts, which means that it can run for a long time with a load power not exceeding 1200W. However, if you want the inverter to run for a long time, you need a battery with sufficient capacity to use with the inverter.
Calculation of battery capacity
The capacity of common batteries in life is usually expressed in ampere-hours (Ah), and the battery voltage is expressed in volts (V). To calculate the battery capacity required for a 1200-watt inverter, you can use the following formula:
Battery capacity (Ah) = Inverter power (W) × usage time (hours) ÷ battery voltage (V) ÷ inverter efficiency
Assuming that we want to run a 1200-watt inverter for 1 hour and use a 12-volt battery, the inverter efficiency is 90%, we can make the following calculation:
Battery capacity = 1200 watts × 1 hour ÷ 12V ÷ 0.9 = 111Ah
This means that if you want a 1200-watt inverter to run at full load for 1 hour, you need at least a 111Ah 12V battery. If you need to extend the running time, the number of batteries needs to be increased accordingly.
How batteries are connected: series and parallel
The way batteries are connected affects the number of batteries required for the inverter. There are two common ways to connect batteries: series and parallel.
Series connection
A series connection is to connect the positive terminal of a battery to the negative terminal of the next battery, thereby increasing the total voltage without changing the total capacity of the battery. For example, when using 12V batteries in series, two 12V batteries will produce a voltage of 24V, but the total capacity is still the same as a single battery.
For a 1200-watt inverter, if it supports 24V input, you can use two 12V batteries in series, which can reduce the number of batteries and improve system efficiency and operating time.
- Battery consistency: Batteries in series must be of the same type, capacity, and internal resistance to ensure that they charge and discharge at the same speed to avoid overcharging or overdischarging of individual batteries.
- Balanced charging: For batteries such as lithium batteries that have high requirements for charge balance, a balanced charger is required to ensure that the power of each battery is consistent to prevent overcharging or overdischarging.
- Safety: The safety of battery packs connected in series is critical. If one battery fails, it may affect the performance of the entire battery pack and even cause a safety accident. Therefore, corresponding protective measures need to be taken, such as battery protection board, fuse, etc.
Parallel connection
A parallel connection is to connect the positive pole of the battery to the positive pole and the negative pole to the negative pole, thereby increasing the total capacity without changing the voltage. For example, if two 12V 100Ah batteries are connected in parallel, the voltage is still 12V, but the capacity will become 200Ah.
If your 1200W inverter only supports 12V input, you can choose to connect multiple 12V batteries in parallel to increase the capacity of the system and extend the running time.
| Features | Parallel connection | Series connection |
| Voltage | No change | Increase |
| Capacity | Increase | No change |
| Current | Increase | No change |
| Application scenarios | Where large capacity is required | Where high voltage is required |
Factors affecting battery selection
Inverter input voltage
When you choose a battery, make sure the battery voltage is consistent with the inverter input voltage; otherwise, the inverter will not work properly. For example, if your 1200W inverter is rated for a 12V input voltage, then you need to buy a 12V battery to match it.
Duration of use
The time you plan to use the inverter is also a key factor in choosing a battery. If you only need to run the inverter for a short time, a smaller battery capacity may be sufficient. But if you plan to run the device for a long time, you need to choose a battery with a larger capacity.
Load power
Load power is also an important factor in determining battery demand. Higher load power means that the battery will be exhausted faster. For example, when a 1200-watt inverter powers high-power devices (such as microwave ovens, refrigerators, etc.), the battery will discharge faster and you will need more batteries to maintain operation
Battery type
Lead-acid battery:
Advantages: Cheap price, mature technology, easy maintenance.
Disadvantages: Severe memory effect, short cycle life, high self-discharge rate, sensitive to ambient temperature.
Impact on inverter: Suitable for occasions with low requirements for cycle life and cost sensitivity. However, due to its large internal resistance, the voltage will drop faster when discharged at a high rate, affecting the output stability of the inverter.
Lithium-ion battery:
Advantages: high energy density, long cycle life, low self-discharge rate, no memory effect.
Disadvantages: high price, sensitive to temperature, high safety requirements.
Impact on inverter: Suitable for occasions with high requirements for energy density and cycle life, such as electric vehicles and energy storage systems. Lithium-ion batteries have a lower internal resistance and can provide a more stable output voltage, improving the efficiency of the inverter.
Lithium iron phosphate battery (LiFePO4):
Advantages: high safety, long cycle life, and wide operating temperature range.
Disadvantages: relatively low energy density and high cost.
Impact on the inverter: Suitable for occasions with high safety requirements, such as energy storage systems and power tools. LiFePO4 batteries are highly safe and can extend the service life of the inverter.
NiMH battery:
Advantages: Small memory effect and resistance to overcharge and over-discharge.
Disadvantages: Low energy density and high cost.
Impact on the inverter: Suitable for occasions with high requirements for cycle life and safety performance.
Ambient temperature
Ambient temperature can also affect the performance of the battery. A cold environment will reduce the efficiency of the battery, causing its capacity to decrease. If you plan to use the inverter in a low-temperature environment, you may need to increase the number of batteries to compensate for the loss of efficiency.
How to choose the right number of batteries
Remember this formula:
Battery capacity (Ah) = Inverter power (W) × Usage time (hours) ÷ Battery voltage (V) ÷ Inverter efficiency
Choosing the right number of batteries depends mainly on the power requirements of your inverter and the usage scenario. Here are some common usage scenarios and their recommended battery configurations:
Short-term use (1-2 hours)
If you plan to use a 1200-watt inverter for a short period of time, such as powering lights and small devices while camping, you can choose a 12V 100Ah battery. This will provide power for about 1 hour.
Long-term use (more than 4 hours)
If you need to use the inverter for a long time, such as powering an RV or off-grid system, it is recommended that you connect multiple batteries in parallel. For example, four 12V 100Ah batteries in parallel can provide 4 hours of runtime for a 1200-watt inverter.
Conclusion
The number of batteries needed for a 1200W inverter should be determined based on your specific needs. You want to make sure that the number of batteries is sufficient for the length of time you plan to run the inverter. When calculating battery capacity, you need to consider factors such as load power, runtime, and battery type. The connection method of series and parallel will also affect the number of batteries and the overall efficiency of the system.
