About: The tension between novelty and familiarity...

Whilst debugging version 0.4 of the SOLAR TRACKER CONTROLLER I spent a lot of time hooking up the multi-meter on diffent NPN switch circuits. The multi-meter did not have breadboard friendly connections. I looked at a few MCU based monitors including TJ's (I later realized I had one of his boards). I remembered I had a few of the CHARGER Doctors lying around, so I created a more versatile breakout for it.

It provides banana plugs, male and female headers for in and out, and alternates the voltage and current to the LCD every few seconds.

There is a review of the module at ELECTRO SCHEMATICS.

Step 1: Materials and Tools

There is a full Bill of Material and Sourcing list.

  1. 3D printed casing
  2. Charger Doctor module (1)
  3. Banana panel mount sockets (4)
  4. Male header (2 * 2P)
  5. Female header long pin (2 * 2P)
  6. 4G * 9mm stainless pan head screws (4)
  7. Tinned wire (200mm)
  8. USB Male Type A Connector (1)
  9. USB Female Type A Connector (1)
  10. Insulation tape (200mm)
  11. Flux pen (1)
  12. Soldering iron and solder (1)
  13. Hot Glue Gun and Glue (1)

  14. Strong Cyanoachrylate Adhesive (preferably brush on)

Step 2: Assembly

  1. Ensure the female headers have long pins; if not sacrifice and replace with long pins.
  2. Glue the male and female headers to the top panel and to one another with the Cyanoachrylate adhesive as shown.
  3. Carefully bend the long pins toward the outside, making contact with the male pins.
  4. Solder the joint, tinning the excess length while you are there.
  5. Assemble the USB connectors, taking note of the red and black polarity marks shown.
  6. Tape insulation to the USB connectors.
  7. Cut the threads of the banana sockets if needed.
  8. Install the banana posts as shown.
  9. Flux and Tin nut on lower banana posts.
  10. Route and solder from banana posts to bent pins as shown.
  11. Place module in void aligning both upper surfaces and secure with hot glue.
  12. Solder tinned wire onto outer pins on USB connectors, ensuring clearance on each other.
  13. Position bottom cover and fasten with screws.

Step 3: Next Steps

  • Hook up the "IN" side to your power source.
  • Hook up the "OUT" side to your load.
  • Monitor the voltage and the current draw.

NOTE: If the load is not consistent (like periodic use of servos), the alternating Voltage/Current display may not be good enough. Also my use case (Arduino Pro Mini 3.3V controlling servos) did not show a current draw when servos were not in use, so 10's of milliamps were not registering.

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    3 years ago

    I find these charge doctors really useful, and could be handy for a lot of 5v projects that don't have usb ports, so this breakout is great.

    Just a thought, it would be useful if you still had the usb functionality. if you had two male and two female connectors, you could extend out the usb connections to the edge of the case. Or I would imagine you could crack the case of the charge doctor, running wires out from the positive and negative of the onboard usb connectors to secondary usb connectors mounted to the new case (as well as the banana clips and pins).

    Also you could include some screw up terminal connections, for greater flexability.

    a really useful build, thankyou


    Reply 3 years ago

    Great that you are looking at the connectivity. Screw terminals is a good one. I have several of these extremely cheap modules, so keeping the USB connectivity was not a priority.


    Reply 3 years ago

    also, a weaker but cheaper and quicker way of doing things would be to dispense with the case altogether, just make up a lead from a female usb connector to two banana plug connectors, two terminal connectors, two pin connectors (and then repeat for the male usb). With a bit of hot glue and heat shrink for strain relief, I think these could be reasonably hardwearing, though obviously less so than the case mounted form. as a bonus, you can still use the usb doctor on its own