Fork me on GitHub

Battery Size Calculator
Calculate the size battery you need for a certain runtime

Formula: Battery Ah - Watts of the load multiplied by the required runtime multiplied by the DoD devided by the desired battery voltage multiplied by the efficiency of the inverter.

If you have a 100 watts 42" TV and a 12V 7ah battery lying around and a UPS for example, then you can work out the runtime using the calculator below.

Reset Calculator

Time Conversion Table

Hours Minutes Total Minutes
1 0 60
1 30 90
2 0 120
2 30 150
3 0 180
3 30 210
4 0 240
4 30 270
5 0 300
5 30 330
6 0 360
6 30 390

Additional information about the calculator

The calculator will show you both Lithium and Lead Acid battery options.

The calculator automatically sets the optimal depth of discharge (DoD) depending on the load and battery type. To prolong the life of a battery, a lead-acid battery should not frequently be discharged below 70%, and Lithium-ion battery not below 20%. Note that 0% is a flat battery and 100% is a full battery.

How do I calculate the charging time of a battery?

If we ignore the losses during charging, divide the battery capacity by the charging current to obtain the battery's charging time in hours.

For example to charge a 100Ah Lead Acid battery using a 5Ah Optimate 6 charger will take roughly ±16 hours to recharge

Some articles you might also be interested in...

How to monitor the power usage of devices using a Sonoff Pow R2
How to monitor the power usage of devices using a Sonoff Pow R2

Sonoff Pow R2 is a 16A WiFi smart light switch that allows you to remotely manage and control your appliances and monitor your home energy usage. The WiFi light switch works like a power monitor, which allows you to keep track of 99% accurate real-time current, voltage and power on your app.

Read The Article
How To Use Your Raspberry Pi To Monitor Internet Speed
How To Use Your Raspberry Pi To Monitor Internet Speed

Testing speed on a regular basis allows you to pinpoint performance trends, isolate which devices may be causing issues for your wireless network, and ensure no one is stealing your bandwidth. This tutorial is made for you if you’re interested in monitoring how your download speed, upload speed, and ping are affected over time. In order […]

Read The Article
The most important plugin for your WordPress website
The most important plugin for your WordPress website

Google’s official WordPress plugin. Get insights about how people find and use your site, how to improve, and monetize your content, directly in your WordPress dashboard. If you have a WordPress website and would like to see how users find and use your website, Site Kit is right for you. To help you build, maintain, and grow your online presence, Site Kit gives you easy-to-understand metrics and actionable insights directly on your WordPress dashboard.

Read The Article