Battery management is a tedious but necessary problem that becomes more of a hassle with lithium-ion technology. As we’re all very aware, such batteries need a bit of care to be utilized safely, and as such, a huge plethora of ICs are available to perform the relevant duties. Hackaday.IO user [Erik] clearly spent some time dropping down the same old set of ICs to manage a battery in their applications, so they created a drop-in castellated PCB to manage all this.

The little board, measuring just a smidge over 22 x 16mm, packs a fair amount of capability, with an ATTiny1616 to make it customisable. The Injoinic tech IP2312, which is intended to be supplied from USB sources, takes care of charging with a programmable current set by a resistor, as is typical. The battery output is switched by a beefy MOSFET, with the output first passing through a measurement resistor and being sensed by an INA219 bidirectional current monitor. This might be useful for monitoring charging via the microcontroller. An APX803 low-voltage lockout/supervisor IC enables an LD56100 LDO to ensure no load is supplied to the battery below the low-voltage threshold. This is important! This provides a 3.3V rail to all the other ICs on the board, which is always on when the battery voltage is high enough. Utilising interrupts in the ATTiny firmware means the controller remains mostly asleep, consuming as little power as possible and preserving battery standby time. Temperature measurement is courtesy of the TMP102 with a ADS1015 quad channel 12-bit delta-sigma ADC also wedged in for some auxiliary sensing. These additional analog channels are not actually used by the module but are presented on the IOs. These could be very handy for detecting external inputs relevant to battery management with some custom Arduino-compatible firmware.

Implementation-wise, [Erik] provides PCB footprint details for both Eagle and KiCAD and an example application circuit detailing hookup and programming. So long as you ensure the UDPI pin in connected to a UART as shown in the application circuit, developing and uploading custom application code should be simple. Check out the project GitHub for more details.

Topics of power management and batteries are plentiful. Here’s a nice, hackable power meter for starters. Here’s an interesting story about extracting perfectly useable LiPo cells from perfectly useless disposable vapes and, finally, a possible method for mitigating electrode damage due to constant current charging.