How Long Will A 12V Battery Last With An Inverter

No doubt, the question everyone asks about inverters. No one wants to drain their battery or waste money on something that won’t last long enough.

A 12V battery is a rechargeable storage device that converts chemical energy into electrical energy. 12V batteries are generally used in 12 volt systems that require 12 volts of direct current for the power supply.

A 12-volt battery is a 12-volt battery, even when there is no load to drain the power supply. 12V DC systems can be used for the power supply of mobile devices such as inverters.

An inverter is a 12V DC to 120 VAC converter used to convert the 12-volt direct current (VDC) into alternating current (Ac).

The 12V battery charges through the 12-volt output of the inverter which has a 12VDC input. A small inverter can run almost anything: TV, DVD player, video games, microwave oven, laptop, lights, fans, cell phone chargers, and many other electronics. There are even inverters available that can power central air conditioners or heat pumps.

12v batteries can last for a few hours depending on the load and other factors involved in powering different 12v devices. 

The first thing that affects how long a 12v battery will last is its capacity, i.e., how much energy (watt-hours) it can hold or store.

If you have a 200 amp-hour battery and you use 50 amp-hours of power from it, then you will have 150 amp-hours that you can use to run your inverter.

It is also important to know at what rate the battery is being discharged, which tells us how much power the appliance is using and how long it should last on a single charge of that battery.

Another factor that affects how long your 12v battery will last with an inverter is the amount of power being drawn from it.

If you have a 200 amp-hour battery and use 100 watts worth of power, then that battery will last for roughly an hour. This means that if you drew 50 watts (half the voltage) from this same battery, it would also only last about an hour.

And finally, the last factor which affects how long a 12v battery will last is the type of load you are using. Not all loads use power equally or even proportionally.

For instance, if I have 2 100-watt light bulbs to use in my house (they both contain 10 watts worth of filament), then one light bulb would most likely last twice as long as the other one (assuming it is a 50/50 draw).

So if you know all these things, then you can figure out how long your 12v battery will last. Just take the power consumption of your device and divide it by its voltage to get its amp-hours consumed per hour.

Then multiply the amp-hours consumed per hour by the amp-hours your battery can store.

If you have a 10 amp-hour device and a 200 amp-hour battery, then 10 amp-hours / 12v = 0.83 hours (14 minutes). Multiply that by 150 amp-hours and you get 22.5 hours, so it should last a little over 1.5 days.

In addition, there is no maximum amount of time that a battery can be used; instead, the life of the unit will depend upon how many times it is recharged.

Charging often can destroy a 12V battery because it causes electrolytes to stratify between plates. Stratification results in partial charging of the battery, which can permanently reduce capacity and shorten life.


The 12v battery will last for a long time when used with an inverter, but the power output is limited. This means you can’t rely on it to power all your devices at once without running down the charge quickly.

However, if you use just one or two items like laptops and cell phones at a time then this battery should be able to run for days or weeks before needing recharging.

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