100Ah battery is very big. They can be used for RVs, as solar batteries, or even as car batteries. You can imagine that one of the most commonly asked questions about a 100 amp hour battery is:

“How long will a 100Ah battery last?”

If you understand the basic electric power law it can be calculated easily:

**Power (W) = Current (I) × Voltage (V)**

100Ah battery can run from anywhere **120 hours** (running 10W equipment) to **36 minutes** (running a 2,000W appliance).

As you can see, how long a 100 amp hour battery will last mainly depends on how powerful you are running the device. To fully answer how long a 100Ah battery will last, we’ll first look at how much capacity (or juice; in terms of Wh or watt-hours) a 100Ah 12V battery will hold.

We will also explain how you can calculate how long a 100Ah battery will last any device. On top of that, you get a**100Ah Battery Life Calculator**‘ Also makes all these calculations easier.

Lastly, we also turn to two real-life examples to illustrate how you can use the calculator. these:

*Example 1:*How long will a 100Ah battery last a device that needs**400W?***Example 2:*How long will a 100Ah battery last the required equipment?**100W?**

The goal here is that once you finish this article, you will be able to determine how long a 100Ah battery will last for any device.

Let’s see how much juice a 100Ah battery has:

### 100Ah Battery Capacity (in terms of Wh)

For starters, we need to determine how much electricity is in a 100Ah battery. some might say, *“It’s a 100Ah battery, that’s where your capacity is.”*

Well, it’s not all that easy. *“100ah”* Only tells us how much current the battery can provide. For example, a 100Ah battery can provide us with 100 amperes of current for 1 hour. It can also provide us 1 amp current for 100h.

To get the electric potential (or power according to P = I × V), we need to know the voltage as well.

Now, almost all batteries have a **12V Output Voltage**, It doesn’t matter whether you have 100Ah lithium battery, 100Ah deep-cycle battery, or 100Ah LiFePO4 battery; All of them run on 12 volts or 12 volts.

With these two key metrics – 100Ah and 12V – we can accurately calculate how much electrical capacity (measured in Wh) is actually in a 100Ah battery. Here is the equation we use:

**Battery Capacity or Watt-hour (Wh) = Amp-hour (Ah) × Voltage (V)**

In the case of a 100Ah 12V battery, we get:

**100Ah 12V Battery Capacity** = 100Ah × 12V = *1,200Wh*

Now, this 1,200Wh battery capacity is the most useful information when it comes to determining how long a 100Ah battery will last. this is **1.2 kW** of juice; For comparison, the Tesla S model has a 100 kWh battery.

Here are some examples of how long such a 100Ah battery will last various devices:

- A 100Ah battery will run a 1,200W appliance for 1 hour.
- A 100Ah battery will last a 600W appliance for 2 hours.
- A 100Ah battery will last a 400W appliance for up to 3 hours.
- A 100Ah battery will last a 100W appliance for up to 12 hours.
- A 100Ah battery will last 1,200W of equipment for 1 hour.

How did we calculate these times? Here’s a simple equation with a ‘100Ah Battery Life Calculator’ that everyone can use:

## 100Ah Battery Life Calculator

Here’s how you see it:

- You have a device you want to run. Let’s say there is a 100W television.
- You have a 100Ah battery. It has a capacity of 1,200Wh.

When will the battery run out of juice? Here’s how you calculate it:

**100Ah Battery Run Time = Battery Capacity / Equipment Wattage**

In our case, it is:

**100Ah Battery Run Time** = 1,200Wh / 100W = *12 hours*

Simple, isn’t it?

We’ve also simplified this by designing an easy-to-use ‘100Ah Battery Life Calculator’. You can enter the wattage of the appliance you want to run, and the calculator will dynamically tell you how long the 100Ah will last.

Here is the calculator (you can play with the numbers):

Using the calculator, you can determine how long any device will last on a 100Ah 12V battery. You can also use this calculated chart of different devices for longer 100Ah battery power:

Appliance Power Draw (Watts): |
How long will a 100Ah battery last: |

10W | 120 hours |

20W | 60 hours |

30W | 40 hours |

40W | 30 hours |

50W | twenty four hours |

100W | 12 hours |

150W | 8 hours |

200W | 6 hours |

250W | 4.80 hours |

300W | four hours |

350W | 3.43 hours |

400W | Three hours |

450W | 2.67 hours |

500W | 2.4 hours |

600W | 2 hours |

700W | 1.71 hours |

800W | 1.5 hours |

900W | 1.33 hours |

1,000W | 1.2 hours |

1,100W | 1.09 hours |

1,200W | 1 Hour |

1,300W | 0.92 hours or 55 minutes |

1,400W | 0.86 hours or 52 minutes |

1,500W | 0.8 hours or 48 minutes |

2,000W | 0.6 hours or 36 minutes |

To illustrate how easy it is to calculate these times manually, we’ll solve two promising examples:

### How long will a 100Ah battery last a device requiring 400W? (Example 1)

A lot of people who have an RV or caravan are interested in how long a 100Ah battery will last if you run a 400W device with it.

If you’re seeing 100Ah alone, it’s impossible to detect.

However, when you calculate a 100Ah battery capacity and get 1,200Wh, you can quickly figure out how long the battery will last:

- You have a 1,200Wh battery.
- The appliance draws 400W.

You just divide 1,200Wh by 400W and get 3 hours.

In short, a 100Ah 12V battery will last a 400W appliance for 3 hours.

### How long will a 100Ah battery last a device requiring 100W? (Example 2)

The same principle applies here as well. We already know that a 100Ah battery will last a 100W device for 12 hours.

This is because we know two metrics that make this calculation possible:

- You have a 1,200Wh battery.
- The appliance draws 100W.

Dividing 1,200Wh by 100W gives the result: 12h.

We hope that now everyone can calculate how long a 100 amp-hour battery will last. If you didn’t find your answer, you can use the comments below, give us some data about the battery and the device you want to run it with, and we’ll try to help.

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