Power Bank KeepAlive (Adjustable)

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 (adjustable 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 keepalive’s low-current draw from your end device will keep your power bank alive.

This adjustable version has a very similar circuit to the assembled KeepAlive, however comes with the ability to adjust the strength of the pulse using the slide switch to three different set values.

Whilst the standard assembled version has a resistor value that works for most projects and power banks, some of our customers asked for the ability to change the value easily, to cater for some awkward power banks and to potentially allow an even lower pulse power consumption.

Plug one end of this into your power bank and the other end into your device, and there you have it – an easy, reliable mobile power source with an adjustable pulse!

Case now available!

We 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.

How does it work?

The Keepalive works by periodically sending a small electrical pulse which, when combined with another device plugged into it drawing a small amount of power, is usually enough to keep a power bank from shutting down.

By default, we would recommend you start on low and only try medium or high if your power bank does not stay powered on. Below are the approximate draws for each of the settings:

• Low = 100mA
• Medium = 145mA
• High = 170mA

Be aware that at the highest setting, a small amount of heat will be generated – please ensure that you do not cover the unit with fabric or similar and air is allowed to flow around the device when in use.

Use cases

Whilst we originally stocked the range of keepalives for small dev board purposes, there have been many interesting use cases that customers have shared with us. It’s great to hear about the weird and wonderful places our keepalives are used!

• Charging Hearing Aids
• Charging earbuds
• Timelapse photography
• Running a mobile Raspberry Pi Pico/microcontroller

Resources

• Documentation
• Printables 3D-Printable Case Design

FAQ

• Will it work with my power bank?
  • As you may appreciate, there are thousands of power banks out there, which means it’s impossible to be able to test and verify with every power bank. We have chosen a middle ground regarding how much power the device draws to balance out keeping a power bank alive while not affecting battery life too much.
  • We can confirm that all of our ANSMANN power banks work with the range of ePlop keepalives.
• Can it keep a power bank alive on its own?
  • No. The keepalive device is designed to work in conjunction with another small power source.
• Can it work with power delivery / QC
  • No. The keepalive is only designed to work at 5v and so can only keep alive 5v devices. If you try to plug it into a PD power supply you risk damaging the keepalive and other hardware.

Package Contents

Select an option before adding to cart. Choose either:

• Option 1: 1x Power Bank KeepAlive (Adjustable) only
• Option 2: 1x Power Bank KeepAlive (Adjustable) + 1x 3D printed case