The RedReactor Battery Power Supply

I have developed a robust, powerful and feature rich battery power supply board for the Raspberry Pi which I believe will work equally well with the Banana Pi family of boards (e.g. M3/M4), therefore I hope you don’t mind if I provide some information about it.

We are in the pre-launch phase for our Kickstarter campaign at . We designed this board as part of creating a portable internet radio and found that existing boards did not provide all the features we needed, or could not reliably supply enough current and steady voltage for the whole system when dealing with peaky demands from the Pi, display, amplifier etc.

Whilst a simple power bank might seem like the obvious solution, they typically fail to either deliver enough power (so you have under-voltage issues causing crashes), can’t provide power whilst being charged (or if they do, causing the battery charging to be permanently on thus reducing battery life), don’t give you access to battery voltage for a safe shutdown, don’t have adequate voltage regulation (which will cause crashes when heavily loaded - as they’re designed for charging batteries, not match peaky power demands), won’t restart unless the load is removed first, and don’t have a way of connecting your own external power button nor read the charging status in software.

The Red Reactor board delivers a very stable 5.1v, with an I2C interface for battery voltage and current for safe shutdown on low battery or when you detect that the external supply has failed (uses 3v3 from the Pi for this), and drives a GPIO to provide the ON button state information with a separate open drain pull down interface for a long-press RESET function. We will be providing one version with pogo-pins to sit directly underneath the Pi, and a version of the board where you can easily wire these connections, and use your own ON button which can also be used for other functions in your software (short press, long press etc) and/or drive it from an RTC alarm.

The circuit design ensures that the 18650 batteries are not under load whilst being charged, allowing the charging cycle to complete accurately, whilst the board only consumes 10uA when off (compared to some designs with CPU’s that consume many mA’s monitoring the ON button!), ensuring maximum battery life. But at the same time, our extreme testing shows a super steady 5.1v output when delivering over 4 Amps, where we used 1 board driving a Pi4, display, USB hub with keyboard, mouse, webcam, and at the same time it was charging the battery of another board connected to a Pi3, also with a display and both running a heavy graphics test case.

If you would like more information and register to be notified when the campaign goes live, please check out for details, including pictures and a video of the extreme testing. We’d love to get your support to achieve our goal and also benefit the Banana Pi community! Of course, feel free to ask questions too. Thank you!

if you want to do your project with banana pi , we will full support you.

Thank you! Your support will be much appreciated.

Based on the information I have seen, our ‘headerless’ version can work with all your BPI boards, whilst the pogo-pin version can mount directly underneath the following models, retaining full access to their buttons and interfaces:

  • BPI-M5
  • BPI-M4
  • BPI-M2-Berry
  • BPI-EAI 80
  • BPI-M2 Zero

It would seem the BPI boards have lower power consumption which can easily be supported by the Red Reactor board, with enough power for many accessories that can be attached to the USB, SATA, camera and 40-pin header interfaces.

Please send me a private message to discuss how we can support each other.

There are some use cases where the system is remote or up-time is critical, yet consume too much power to run for long periods on batteries. So whilst a high performance battery back-up power supply is essential to ensure an orderly shutdown when there is an external power outage, you may also want to restart everything as soon as the external power is restored.

Whilst the Red Reactor can easily support a BPI-M5 with accessories and cleanly switch to battery power, you can also use the Vin port and ON button interface to easily integrate additional functionality into your project. In a previous video we showed how to add an RTC alarm to manage timed power-on and power-off requirements, you can see that at

We’ve now also created a short video at on how to add a simple circuit to detect when external power is restored, which connects to the Vin port and operates alongside an ON button to create a trigger (even if you’re using USB as the power input). A simple script will detect a power outage over I2C and perform a safe shutdown, whilst the system is automatically rebooted when external power returns!

I hope you’ll find these videos useful. Please don’t forget to register at our site for more information. Thank you!

1 Like

Just wanted to give you a quick update on our progress. We were expecting our Kickstarter campaign to go live this week but unfortunately the world’s shortage of ICs (as you’ve no doubt read about in the news) has affected one of the components on our board. We obviously don’t want to present a delivery schedule that we cannot commit to, so we’ll look at alternative suppliers and solutions first.

We’d be happy to hear if you know of suppliers’ stock for this particular component (INA219AIDCNR/INA219AIDCNT) or had good results with comparable, alternative parts. We’ll let you know how we get on!