Fuel Tank BoosterPack
The Fuel Tank BoosterPack provides an all-in-one LiPo solution, including charging and monitoring.
It supplies the LaunchPad with 3.3V and 5V. The 1300mAh capacity is rather impressive, especially when used with ultra-low power MSP430 MCUs.
The BoosterPack has two LEDs, one for low charge and another for charging. There are two connectors, one for the LiPo battery and a micro-USB for recharge. Unfortunately, there's no general switch.
The Fuel Tank BoosterPack MK-II brings a welcomed update with many improvements.
The BoosterPack includes four integrated circuits:
The 4 ICs and the 2 LEDs
Library for Energia
At the core of the Fuel Tank BoosterPack, there is the impressive all-in-one system-on-a-chip BQ27520 that provides System-Side Impedance Track™ Fuel Gauge With Integrated LDO.
The BQ27520 monitors the LiPo cell and provides useful statistics with nominal and actual values for voltage, capacity and current, as well as remaining time to empty.
I've developed a library for Energia, an easy-to-use Processing-based Wiring-derived Arduino-like IDE, with embedXcode, a template for Xcode.
The library provides the basic statistics, as shown on the right.
Some pins seem to have been selected at random, jeopardising some useful ports.
To free the 3 pins 2, 5 and 7 on the LaunchPad J1 connector and thus recover the UART, I²C and SPI ports, just remove the 0Ω resistors R11, R12 and R13 as per the schematics.
The I²C pins are compatible with the MSP430G2 and MSP430F5529 LaunchPads. For the Stellaris now Tiva C Series LaunchPad, the R9 and R10 0Ω shunts should be kept in place, actually requiring four pins, PD_0 = PB_6 and PD_1 = PB_7.
If the R9 and R10 0Ω shunts are removed from the Stellaris now Tiva C Series LaunchPad, an additional bit-bang I²C library is required.
Unfortunately, the Fuel Tank BoosterPack suffers from power leakage.
Depending in the tool used to perform the measure, leakage goes from 15 mA up to 20 mA.
To fix this, remove the 10kΩ resistors R18 and R20 and install pulldown 10kΩ or 22kΩ resistors in R17 and R19. Find more details at the bottom of this other review Element14's Fuel Tank BoosterPack.
With this new configuration, leakage is solved with new value down under 0.2 mA.
The pin numbering on the schematics is rather confusing as it doesn't comply with the standard.
For example, the schematics consider only two connects, JP1 and JP2, when the standard considers four, J1 and J2 for 20-pin LaunchPads and additional J3 and J4 for 40-pin LaunchPads. JP1 pin 19 of the schematics actually corresponds to standard J1 pin 10, available for all the LaunchPad, including the MSP430G2.