PortaPack H4M Battery Size and Polarity Checklist

[Pavel]

Short answer: A PortaPack battery is compatible only when chemistry, nominal and full-charge voltage, physical dimensions, connector type, wire order, polarity and protection match. Never trust red and black wire colours or connector fit without measuring polarity.

Before you start​

• Confirm the exact HackRF and PortaPack hardware revision, then match the firmware image and application files to that target.
• Perform transmit tests into a rated 50-ohm dummy load through suitable attenuation and filtering, not into an antenna.

Step-by-step method​

1. Step 1: Check the exact H4M enclosure's maximum battery dimensions and cable clearance. Leave room so the cell is not bent, pinched or pressed by screws and PCB edges.
2. Step 2: Use the battery chemistry and voltage specified for the charge circuit, commonly a protected single-cell lithium pack where documented. Verify the pack includes the required protection rather than assuming the PortaPack supplies it.
3. Step 3: With the battery disconnected from the PortaPack, measure connector polarity using a multimeter and compare it with the device socket diagram. Re-pin the connector only with insulated tools and the battery safely isolated.
4. Step 4: Perform the first charge on a nonflammable surface while monitoring temperature, swelling and reported charge state. Disconnect immediately if the pack or board becomes abnormally hot.

Concrete example​

Two 2-pin JST-style connectors can be mechanically identical while positive and negative are reversed. A 3.7 V label also does not describe protection, capacity authenticity or physical fit; every item must be checked independently.

How to judge the result​

A suitable battery fits without pressure, has correct measured polarity and voltage, charges without abnormal heating and powers the unit through a controlled run test without sudden shutdown.

What to record​

• For receive gain, start with RF amp off, IF gain 16 dB and baseband gain 16 dB, then change IF and baseband gradually while watching distortion and noise.
• Verify USB stability at a modest sample rate before attempting wider captures.
• A successful firmware update boots the correct target, reports the intended release and retains stable USB communication.

Common mistakes​

• Changing several hardware, software or RF variables at once, which removes the controlled comparison needed to identify the cause.
• Treating one autoscaled screenshot or one unusually good result as proof without recording the settings and repeating the test.
• Forcing a thick cell beneath the board or closing the case against it creates puncture and swelling risk even if the electrical specifications are correct.

Final check​

Power-cycle the HackRF or PortaPack and repeat the controlled test. Confirm the reported firmware, USB stability and RF safety path before treating the result as complete.