LiPo Amigo (LiPo/LiIon Battery Charger)

by Pimoroni

A range of compact, convenient USB-C LiPo/LiIon battery chargers, perfect for feeding hungry batteries.

We've spent quite a lot of time at Pirate HQ over the last few weeks figuring out ways to charge up batteries for our Badger 2040s, and we've come up with all sorts of horrible solutions. Good news though - you won't have to make do with dubious bits of left over prototype, because we've made some straightforward, small LiPo battery chargers that are just the job.

LiPo Amigo is a stamp sized board with a USB-C connector on one end and a JST-PH connector at the other so you can plug in a LiPo or LiIon battery. Betwixt the two, you can find a perky red LED that will light up to tell you when battery charging is happening. Simples!

LiPo Amigo Pro is a bit larger and has some additional tricks up its sleeves. It's got two JST-PH connectors so you can charge your battery and power your device at the same time (and switch seamlessly between USB and battery power). It also has a power on/off button and extra built in battery protection.

Both are compatible with any of our LiPo, LiIon or high capacity LiIon batteries (batteries are sold separately).

Features

Obligatory LiPo warnings

LiPo and LiIon batteries can be dangerous if not treated with respect! You should only use LiPo Amigo boards to charge 3.7V LiPo or LiIon batteries, and you should make sure that any project involving LiPos is sufficiently protected from being dented, bent, punctured or crushed.

We recommend only using LiPo batteries that have own internal protection against overcharge, over discharge and short circuits (all the ones we sell do).

If you're using a battery bought from elsewhere, double check that the polarity of the wires matches the markings on our board (red to + and black to -) before you plug it in! Some battery manufacturers attach the JST connector the other way up.

Notes

  • Measurements: LiPo Amigo - 26 x 21 x 7 mm, LiPo Amigo Pro- 36 x 23 x 7 mm (LxWxH, including connectors)
  • * The pads on the back labelled FAST CHARGE can be bridged with solder to allow charging at up to 500mA (instead of the default 200mA). Don't do this if you're using an unprotected battery.
  • The battery protection IC on LiPo Amigo Pro limits charge and discharge to about 1A. The pads marked NO PROTECT can be bridged to disable this (no protec, only attac). Only do this if you're using a battery with its own protection that can handle the higher discharge current. We wouldn't recommend trying to draw more than 2A from the battery, as this is the max rating of the JST-PH connectors.
  • ** You should only use the DEVICE connector on LiPo Amigo Pro for powering devices that can handle 4.2V - that's the maximum potential voltage that can be supplied by a fully charged LiPo. Don't plug in things like micro:bits that can't deal with LiPo voltages!
  • The DEVICE connector draws its current from the attached LiPo so it will only provide power if a battery is plugged in. There's no boost circuitry on board, so it won't power Raspberry Pi computers or other devices that need 5V.
  • For connecting your device to LiPo Amigo Pro, we'd suggest using this double-ended JST-PH cable or this JST-PH wire assembly.
  • Because we hate leaving unused space on our PCBs, we've broken out a bunch of other headers that you might find it useful to solder things up to.
    • The LED headers can be used to connect up an external LED to show charging or on/off status - useful if you're building your battery charger into an enclosure.
    • The SW headers can be used to add an external on/off switch to enable and disable the power output of LiPo Amigo Pro. The battery will still charge when the power output is turned off.
    • VBAT is the battery + pin (the same as the positive pin on the BAT JST connector)
    • VDEV is the device + pin (the same as the positive pin on the DEVICE JST connector.