At the top edge of the board is the USB Type C connector. It has 5.1k CC resistors so it will work with any computer or power supply to get 5V and up to 1A.

• DCIN - On the right side of are the board are the DC or solar input pads. They can be used to connect a 5 ~ 18V power supply, which can be used instead of USB. If the input is a solar panel, the charging chip will adjust the current draw so that the voltage does not dip below the battery.

• BATT - At the bottom of the board is the JST battery connector, labeled BATT on the board silk. By default, the output is 3.7V nominal / 4.2V max battery chemistry/voltage for all modern 1-cell LiPoly or LiIon batteries with a default charge rate of 1A.
  This output is available on the right side of the board as well. You can use this secondary output to monitor the voltage on the battery with a multimeter.

• LOAD - At the bottom of the board is the JST load output connector, labeled LOAD on the board silk. It provides a regulated 4.5V-max load output. No matter what voltage you have on the USB or DC / solar inputs, the load output port will never go above 4.5V due to an internal voltage regulator. Keep this in mind, though, when dealing with high currents and high DC voltages as the LDO will make the board start to overheat and throttle the current. 
  You can monitor the voltage on the load via the secondary pads on the right side, if necessary, with a multimeter.
  

If the load connector is drawing current while the USB / DC/Solar power is attached, it will default to drawing current from the charger and any left over current will go to the battery. That keeps your battery from constantly charging/discharging which will reduce the battery life. The max draw from USB / DC / Solar is still 1A, if you need more current it will come from the battery and the chip can provide up to 3A current spikes from the battery to the load output!

• TH and jumper - This is the thermistor pad. You cut the TH jumper and you connect a 10K thermistor to the TH pad which will adjust the charge rate to keep the battery from overheating.
• VS and jumper - This is the voltage setting pad. If you are using LiFePO4 batteries instead of 1-cell LiPoly or LiIon batteries, you can cut the VS jumper and solder the 3.65V jumper on the back closed.
• IS and jumper - This is the current setting pad. You can cut the jumper to change the charge rate with the current jumpers on the back of the board.
• S1 - This is the Status 1 pad. It is connected to the red FAULT LED.
• S2 - This is the Status 2 pad. It is connected to the orange charge (CHRG) LED.
• /CE - This is the chip enable pad. You can pull this pad high to disable the chip.

• Change current jumpers - on the back of the board are two jumpers to change the charge current rate. If you cut the IS jumper, you can solder one of these jumpers closed to set the charge current to 500mA or 250mA instead of the default 1A.
• Change voltage jumper - on the back of the board is a single jumper to change the voltage range to 3.2V nominal / 3.65V max instead of the default 3.7V nominal / 4.2V max. This voltage range is used for LiFePO4 batteries. You will need to cut the VS jumper first before soldering this jumper closed.

• CHRG - This is the charge status LED. It is an orange LED. It is connected to the S2 (Status 2) pin on the left side of the board. It will be lit while a battery is charging. 
• FAULT - This is the fault status LED. It is a red LED. It is connected to the S1 (Status 1) pin on the left side of the board. It will be lit if the board experiences a fault condition. The bq25185 has integrated fault protection for a few conditions:
  
  • Input overvoltage protection
  • Battery undervoltage protection
  • Battery short protection
  • Battery overcurrent protection
  • Input current limit protection
  • Thermal regulation and thermal shutdown
  • Battery thermal fault protection
  • Safety timer fault
  • ISET and ILIM/VSET pin short/open protection.
• PWR - This is the power good LED. It is a green LED. If the the board is powered properly, this LED will be lit.