Charges a 18650 battery from solar panels (up to 3), and breaks out 2 power out connectors (with switch). Originally devised for the SOLAR TRACKER (Rig and Controller), it is fairly generic and will be used for the upcoming CYCLING HELMET SOLAR PANELS.

The controller screws directly onto the battery holder, minimizing the footprint and lead lengths.

Step 1: Materials and Tools

There is now a full Bill of Materials and Sources list.

3D Printed parts
Protoboard (1)
TP4056 (1)
JST XH Connectors (5 or 6)
1N5817 Diodes (3)
SPDT PCB Switch (0 or 1)
18650 Battery (1)
18650 Battery Holder (1)
Strong Cyanoacrylate glue (1)
Hookup wire
Solder and Iron
Tinned wire (or diode lead cutoffs)
4G x 6mm stainless pan head self tapping screws (4)
Male header pins (6)
Sharp straight pick

Step 2: Building the Circuit

The curcuit has 2 variations: onboard PCB switch and a breakout for an external switch.

Cut the protoboard to 71mm x 17mm with 28 x 6 holes showing
Solder 2P (2) and 1P (2) male headers to undersind of TP4056
Bend pins slightly to center of TP4056 so they match the protoboard spacing.
Insert USB side of TP4056 into holes 12 from end of protoboard, ensuring pushed in to plastic collars on pins and solder off
Solder JST XH sockets: 5 for onboard switch, 6 for external switch.
Solder SPDT PCB switch (if using onboard switch)
Place diodes on topside through holes, with cathode line closest to TP4056
On underside, solder anode end of diodes to + on JST XH pins, and cathode end to IN+ on TP4056
On underside, trace and solder - on JST XH (IN) pins to IN- on TP4056
On underside, trace and solder B- and B+ on TP4056 to the edge of the protoboard
On underside, trace and solder - on JST XH (OUT) pins to OUT- on TP4056
On underside, trace and solder OUT+ on TP4056 to centerping on SPDT.
On underside, trace and solder outer SPDT pin to + on JST XH (OUT) pins.
If not using SPDT (alternative external switch breakout) solder to replacement JST XH pins instead (polarity observation not necessary).

Its been noted that the onboard USB charger on the TP4056 is not accessible with this layout; that will be addressed in the PCB version of this project.

Step 3: Assembling the Pieces

Before starting I suggest you verify the TP4056 and switch are working.

Take the battery holder and route both wires through base hole on one end
Then route those wires throgh the matching hole on the 3D printed base
Align both bases, flats touching, and create pilot holes with sharp straight pick into battery holder through 4 corner holes
Fix bases together with 4G x 6mm pan head screws (4)
DRY RUN: place circuit into 3D printed base, and fit appropriate 3D printed lid; make minor mods fo a good fit and remove lid and circuit
Solder battery + and - to B+ and B- rails on circuit with wires trimmed to good length for final assembly
Place a good dob of hot glue in 3D printed base and place in circuit; whilst glue is hot dry fit lid moving the circuit to align with lid voids
Allow glue to dry and remove lid
Put drops of Cyanoacrylate on sides of lid where they will tough inside walls of base
Fit lid aligning top surface with base walls top
Add the appropriate label to fit the lid you have used
Fit 18650 battery.

Step 4: Integrating Into Your Project

Up to 3 solar panel circuits can be connected to the charge controller
Ensure the voltage of each solar panel circuit is ~5V, and the total current of all circuits is 200mA to 300mA
Estimate the power consumption of your needs and only use the second power output if is within range.
If the power supply is concealed and not within easy reach, use the external switch breakout and place your own switch; be mindful to keep leads as short as possible.