This product is similar to our popular KeepAlive Kit but comes pre-assembled and pre-soldered, making it easier and more compact!

Most power banks will automatically turn off their USB ports when the power/current being drawn is lower than a certain value. This makes it impossible to run low-power devices on a power bank, such as a Raspberry Pi Pico, small microcontrollers or even charge your AirPods.

...until now! This is a USB KeepAlive (assembled version) which does exactly that - it keeps your power bank 'alive' by pulsing a small amount of current (via a 555 timer - neat) through the USB port. The pulse, combined with the low-current draw from your end device, will keep your power bank alive.

You plug one end of this into your power bank, the other end into your device, and there you have it - an easy, reliable mobile power source.

This is the pre-assembled fixed-resistor version - ready to go with no soldering required - and sits a little more compact than the original kit version. If you would like the ability to change the resistor value, you can find an adjustable version here, or grab the kit version here to choose your own value. If you need something even more compact, check out the USB-C version.

You can also 3D print a snap-together case for it. Just download the V2 file from Printables, grab some filament and away you go.

Updated version

New V2 board - now even more compact thanks to a fancy new mid-PCB USB connector!

We also now offer a snap-together FDM PLA 3D printed case option, so you can now buy the board on its own, or the board with a case.

Power Bank Compatibility

We've tested all Eplop KeepAlives with the ANSMANN power banks we stock, and they work perfectly together.

Your mileage may vary! We can't test every power bank out there; however, Colin from Eplop has created these KeepAlives with values that should work with most.

The pass-through should work with all devices as the data lines are unaffected. With the resistor values chosen on its own, it should not keep most power banks alive, but combined with a very low-power device, it should be enough to stop the power bank from powering off.

From the Designer

When I'm working on small projects, I like to power them from a power bank or a similar item. Sometimes, the device draws such a small amount of power that it shuts down the power to the USB port as it thinks the device is off.

This device that I've designed will stay on by pulsing the power line to ensure that it doesn't shut down. It utilises the 555 timer in an Astable circuit. With the configured resistors and capacitor, there is a 50% duty cycle, which equates to roughly a 10mA draw with a pulse of approximately 100mA. Combined with the draw of the device, this shall be enough to keep the power bank active. The data lines are directly connected and unaffected. - Colin Hickey

Resources

KeepAlive (Assembled) Documentation
Troubleshooting
3D-printable cases:
- V2 Printables 3D Printed Case Design
- V1 Thingiverse 3D Printed Case Design
Eplop Discord community

Package Contents

Select an option before adding to cart. Choose either:

Option 1: 1x Assembled KeepAlive (v2.0) only
Option 2: 1x Assembled KeepAlive (v2.0) + 1x 3D printed case

Revision History

As of 12/08/2025 - we are now shipping version 2.0, which has a shorter body thanks to a new fancy mid-PCB USB connector, making everything a bit more compact. The specs and characteristics remain the same.

Eplop Products