Efuse and Battery Inrush test plan

Owned by Jerry Tian
Last updated: 2024-08-21
2 min read

Goal: Make sure efuses are soldered properly & Test efuses over current protection and short circuit protections

 

Pre-test preparation:

  1. Try to borrow an eload from Rover or Midnight Sun,

    1. if you can’t borrow the eload, make your own eload. Find the XT60 connector with around 10 resistors soldered together, it should have resistance labelled on it, around 1.67 ohm if I recall correctly. It is in a yellow connector organizer kit.

  2. Set up eload if you can borrow one

  3. Set up scope

    1. Vin channel

    2. Vout channel

    3. Iout channel, for this you need a current probe and it needs a 9V alkaline battery (Rockery has 9V battery if we don’t have any battery left)

  4. Lift R1 to disable buck

  5. Solder a wire at C15, connect power supply here to inject 6V

  6. For each efuse,

    1. Solder 2 wires at output, use one wire for load and another wire to measure Vout;

    2. Solder 1 wire at input to measure Vin

  7. Solder 2 ground wires

 

Test plan:

Check

  • No shorts caused by soldering rework on the PCB

  • Vout is 6V

  • Current Probe is working

 

Over Current Test

  1. Set eload to CC mode, load 1.2A, keep the load off

  2. Set Oscilloscope to Normal, trigger around 0.1 - 0.3A, we want to see the efuse retrying

  3. Turn on power supply

  4. Turn on eload

  5. Take a photo of Oscilloscope screen

  6. Repeat for all efuses

 

Short-to-ground Test

  1. Set Oscilloscope to Normal, trigger around 0.1 - 0.3A, we want to see the efuse retrying

  2. Turn on power supply

  3. use the load wire at efuse output, short it to any ground on the PCB (seeing spark is fine)

  4. Take a photo of Oscilloscope screen

  5. Repeat for all efuses

 

 

Battery Inrush Test

make sure to use two old batteries

  1. Put two batteries in series

  2. Solder input XT60 connector

  3. Probe Buck Vin, Sw node, Buck Vout, Buck Iout. Label the channels

  4. Set eload to Load imax which is 4A at buck output

  5. Turn on eload

  6. Set oscilloscope to single, trigger on half of buck vin rising edge

  7. On the oscilloscope, please capture

    1. Vin

    2. Iin

    3. Vout

8a. Try with a power supply first, set its output current slew rate to max, then connect the circuit before turning on the power supply.

8b. Plug in battery

 

 

Battery Inrush Test (Run #2)

  1. Make sure to put 2 batteries in series, Vin should be around 44V

  2. Probe

    1. Buck Vin at C3

    2. Buck Iin on the power wire between battery and input XT60 connector

    3. Vout at D2

  3. Set eload to 0.1A

  4. Turn on eload

  5. Set oscilloscope to single, trigger on half of buck vin rising edge

  6. Take a screenshot of Vin rising at startup, zoom in on the Vin overshoot behavior

 

Once you are done please place the oscilloscope screenshots in

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