Why?

For some time I wanted a solution to power outages that can happen without warning for various reasons (do you ever find your alarm clock blinking when coming home then wondering if your Pi survived that?). My RaspberryPi runs on power supplied through ATXRaspi but when mains power goes out, the Pi will be cutoff without a proper shutdown, which can damage the OS image and if you’re away and depend on the Pi for home automation or other critical functions and the SD gets corrupted from a sudden power loss, it can be an issue. Adding to that thought, at least several people wanted a way to be able to install Pi’s in their cars or in some unusual project where external power is cutoff as soon as ignition is turned off, but they wanted the Pi to then self-shutdown or allow it to have that extra time it needs. So I started thinking of a PSU board that will have the features of ATXRaspi but also integrate a LiPo battery and act as a backup PSU in case of outages. So I came up with this: MightyBoost, a new project that is providing a pack of features:

I tried to make it as flexible as possible. It has many uses, but primarily targeted towards being a smart backup PSU for critical systems which depend on power staying ON during outages or require clean shutdowns. It is not intended to be an ultra low quiescent current 5V power supply. PowerShield is a much better candidate there.

During initial testing I was able to pull 1.5amps without an issue and only minor warming of the board. However a hefty LiPoly is required to provide enough current for boosting, I used a 2Ah battery. For timed testing I used a 500mA load and a fully charged 2Ah battery lasted 1hr50min before the LiPoly voltage reached 3.3V and was in rapid decline. The new Pi B+ models should be more power conserving (according to press releases and community benchmarking) but 500mA should be a reasonable load for most Pi users. A useful feature is charging your iPad or iPhone when you need that extra juice. Here’s a shot with a “vintage” Moteino-R1 charging an iPhone: