12 Volt Battery Inverter

Written by <strong>Kevin Miller</strong>
Written by Kevin Miller
Last Updated on October 15, 2021
12 Volt Battery Inverter - Calculate How Long it will Last

The 12 V are types of lead batteries constructed using six single cells connected in series where each cell produces approximately 2.1 volts. They have a full charge output of 12.6 volts. They are used mainly in recreation vehicles, boats, and other automobile systems.

From a technical point of view, the batteries use one or more cells to initiate a chemical reaction, thus creating a flow of electrons in a circuit. Batteries do not generate energy; instead, they store energy ready to use when you need it.

The power you get from a lead-acid 12 V battery is direct current which is quite different from what you get at home with the alternating current. Therefore, you can change the state of the battery’s energy from direct electric current to alternating electric current by using an inverter.

You can connect the 12 V lead-acid batteries in parallel or series for maximum voltage or more energy storage capacity. When two 12 V batteries are connected in parallel, you will have a system that will power the same device twice as long as a single 12 V battery. In contrast, if you connect two 12 V batteries in series, the resulting system will be a 24-volt system.

Types of 12 V Batteries

Starter batteries have proved their efficiency in many cars around the globe, and with continuous innovations and development, new types of batteries have been produced. Let us look at the types of batteries we have.

Wet cell batteries (SLI)

Convectional batteries like lead-acid batteries are the most common types of wet cell batteries that work with SLI technology related to the battery’s main functions like starting, lighting, and ignition. They are suitable and convenient for vehicles without start-stop technology.

EFB batteries

EFB refers to an enhanced flooded battery representing an optimized and higher-performance version of the wet battery. EFBs have a large number of possible charging cycles and provide more performance than conventional batteries. They are mainly used as replacements for traditional lead-acid batteries.

AGM batteries

AGM batteries are designed for high demands and have high performance. They can withstand three times more cycle life than conventional starter batteries and are not dependent on their position since the electrolyte is bound to a special glass fiber separator.

How long will a 12v Battery last with an Inverter?

Honestly, you can’t tell the exact duration a 12v battery lasts when connected to a device draining its charge. However, you can determine how long will a 12 volt battery run an inverter depending on how many watts load and amp-hour the battery has. In general, a battery lasts about 10-17 hrs with a 12-volt battery inverter.

Why Batteries last for a Limited Time

Batteries work by creating current flow in a circuit through exchanging electrons in ionic chemical reactions. Due to a limited number of molecules in batteries available to react, the amount of total charge that the battery can push through the circuit before the energy reserves are exhausted.

Calculating battery’s run time

Batteries provide a reserve capacity that generally approximates the amount of time they can last without a recharge. However, the given values contain many assumptions that are significantly compromised in an old or used 12v battery.

To determine how much time a battery will last, we use a 12v battery run time calculator method, which calculates the battery’s total capacity and dividing the value by the circuit power.

For instance, if the reserve capacity is 120, multiply it by six and multiply the product by the battery’s rated wattage to get 1,890,000 as the overall energy. Divide this value by 12volts and divide the result by the circuit’s current, for instance, 20amps, to get 7,575. The value you get is the run time in seconds thus, divide it by 3600 to convert it into hours which is 2.19, approximately 2hrs 10mins.

List 12 volt battery runtimes with different AC loads
Home Appliance Rated Load (watts) Estimated Running time (hours)
Vacuum Cleaner 500 1.2
WiFi Router 10 60
Fridge 120 5
Electric Shaver 15 40
Freezer 40 15
Laptop Computer 100 6
Water Filter and Cooler 80 7.5
Pedestal Fan 60 10
Tablet Charger 10 60
Fluorescent Lamp 30 20
Air purifier 25 24
Coffee Maker 800 0.75
Deep Freezer 25 24
Treadmill 300 2
Portable Air Conditioner 70 (average per hour) 8
Ceiling Fan 60 10
12 volt battery inverter circuit diagram

12 volt battery inverter circuit diagram

The above 12V DC to 220V AC Inverter Circuit diagram uses 2 power IRFZ44 MOSFETs for driving the output and 4047 IC astable multivibrator operating at a frequency around 50 Hz.

Calculating battery’s remaining time

Battery capacity is usually measured in milliamps-hours (Mah). To find out how much time a battery is left with, we use a 12v battery life calculator method. For example, if a battery has 300 mAH capacity and offers a two mA average current load, it is estimated to last 150 hrs. You get this value by dividing the battery’s capacity by the amount of power drawn per hour. However, charging and discharging batteries have an impact on battery life.

How to increase the 12volt Battery lifespan.

One of the best ways to increase battery life is installing an automatic load shut-down that ensures the battery is not drained below 15% of original power. Also, you should ensure that the battery is fully charged to avoid sulphation. 

To maximize battery life, it is recommended that you recharge a battery with the recommended battery charger every 3-month to maintain an uppermost performance. Whether your battery is fully charged, using a proper multi-stage battery charger will benefit the battery’s overall health.

It is also essential to purchase durable and efficient 12volt batteries. The best 12volt batteries include NOCO GENIUS10 12V Battery, LiFePO4 12V lithium battery, and Weize 12V deep-cycle AGM battery.

Uses of 12 v Batteries

There are many ways through which 12 volts batteries may be utilized to fit human needs, from powering everything in your vehicle and other batteries providing a vast amount of power for broader range use.

12 volt battery can also be used to run all equipment rated 12 volts such as an air conditioner, air cleaner, grill, coffee makers clocks, battery-operated clocks, heaters, shavers, fans, cookers, coolers, electric blankets, and many more.

Related article: How to restore a dead car battery at home.


Q: How fast will the power inverter drain battery
A: Most small inverters will drain automobile and marine batteries in 30-60 minutes

Q: How long will a deep cycle battery power an inverter
A: 12volt 100 Ah deep-cycle battery with regular 50% discharge depth would run a fully loaded 1000watt inverter for approximately 34 minutes.

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