Billed as the only battery management board in this form factor that requires no code, JuiceBox Zero can be used as a plug-and-play device to provide portable power to your Raspberry Pi Zero. Well, it’s not quite plug-and-play, since you first need to solder on a stacking GPIO header (not supplied) and also provide your own battery.

It’s compatible with any 3.7 V or 4.2 V single-cell Li-ion or LiPo battery with a two-pole JST PH 2 mm connector, 1 A current output, and 1 A charge rate. Note: while we’re informed that multi-cell batteries may work, they should only be used if you know for sure they have a reliable cell-levelling mechanism – if in any doubt, don’t risk it!

Put it together

To mount the JuiceBox Zero on your Pi Zero’s GPIO pins, you’ll need to add your own stacking header: the online instructions advise mounting this on the Pi Zero first, adding a couple of stand-offs (not supplied) to secure the JuiceBox Zero on top, then soldering the header pins. Using a stacking header will enable you to add a pHAT/HAT on top. There shouldn’t be any pin conflict issues since the JuiceBox Zero only uses power, ground, and GPIO 16 (can be changed to GPIO 25).
That GPIO pin is used to trigger an optional automatic shutdown (after you add a single-line cron job) if the battery voltage falls below 3.2 V, at which point a low-battery red LED is also lit.

As well as providing power to the Pi, the JuiceBox Zero doubles as a battery charger. Just plug a standard 2 A or greater supply into its micro USB port; there are helpful LEDs to indicate when the battery is charging and fully charged. A nice bonus is the inclusion of a handy on/off slider switch and mounting holes for a Pi Camera Module.

Last word

4/5

Unlike the rival PiJuice, there are no extensive software-based power management options on offer, but the JuiceBox Zero does its job well, providing portable power and doubling as a battery charger. When plugged into the mains, it can also be used as an uninterruptible power supply (UPS).