~ Powering low current electronics projects with power banks

Power banks have become a staple for charging smartphones, tablets, and other devices on the go. They seem ideal to power small microcontroller projects but, they often pose a problem for low-current applications. Most modern power banks include an auto-shutdown feature to conserve energy when they detect a current draw below a specific threshold, often around 50–200mA. The idea being that the power bank can shut off after charging a smartphone. However, if you rely on power banks to power DIY electronics projects or remote applications with low current draw, this auto-off feature can be a significant inconvenience.

To address this issue, consider using power banks designed with an “always-on” or “low-current” mode. These power banks are engineered to sustain power delivery even when the current draw is minimal. Look for models that explicitly mention support for low-power devices in their specifications. If replacing a power bank isn’t an option, you can add a small load resistor or a USB dummy load to artificially increase the current draw. It works, but feels wrong and dirty.

For a previous electronics project I bought a power bank randomly. After a bit of testing, I determined that the minimal power draw was around 150mA, so I added a resistor to increase current draw. Only afterwards did I check the manual of the power bank and noticed, luckily, that there was a low-current mode. I removed the resistor and improved the battery life of the project considerably. If you want to power your DIY Arduino or electronics project, first check the manual of the power bank you want to use!

Edit: after further testing it seemed that the low current mode of this specific power bank still shuts down after a couple of hours. Your mileage may vary, and the main point of this post still holds: check the manual of your power bank. Eventually I went with a solution designed for electronics projects.

UGent, Code, and Projecten