2026-06-14, 02:26 AM
(This post was last modified: 2026-07-08, 06:52 PM by dusan.
Edit Reason: typo
)
High Current Load Test Results
I completed load testing of the board using halogen headlight bulbs as the load.
At approximately 30A, the measured voltage drop was 221mV across the reverse-protection MOSFET, the current sensing resistor and the bottom bridge MOSFET path, including the associated PCB traces, connectors, and other resistive elements in that measured section. This corresponds to approximately 7.6mΩ for the measured part of the path.
The complete active current is estimated to be around 11.09mΩ, that corresponds to an estimated total dissipation of about 9.2W.
The limiting factor turned out to be the software thermal protection, which is currently set to shut down at 60°C. The board reached that temperature at 30A during sustained operation.
I also ran a test at approximately 30A with a fan blowing across the board. In that configuration, the temperature stayed around 45°C (Ambient 28°C) showing that even modest airflow significantly improves cooling. Unfortunately, I couldn't continue that test for longer than 1h because my improvised load bank failed rather dramatically and ended the experiment.
Overall, I'm very happy with the results. The hardware appears to comfortably handle the target current, and the thermal performance is in line with expectations.
Based on these results, I would expect the board to operate comfortably in the 20–25A range without forced cooling when installed in a large enclosure with good ventilation. For installations in smaller or sealed enclosures, or where ambient temperatures may be elevated, I would recommend fitting a fan to provide additional thermal margin.
I completed load testing of the board using halogen headlight bulbs as the load.
Code:
Current Voltage Drop Temperature
12.2A 78mV 34°C
15.1A 98mV 35°C
19.1A 130mV 38°C
22.2A 153mV 44°C
26.5A 197mV 55°C
29.8A 221mV 60°CAt approximately 30A, the measured voltage drop was 221mV across the reverse-protection MOSFET, the current sensing resistor and the bottom bridge MOSFET path, including the associated PCB traces, connectors, and other resistive elements in that measured section. This corresponds to approximately 7.6mΩ for the measured part of the path.
The complete active current is estimated to be around 11.09mΩ, that corresponds to an estimated total dissipation of about 9.2W.
The limiting factor turned out to be the software thermal protection, which is currently set to shut down at 60°C. The board reached that temperature at 30A during sustained operation.
I also ran a test at approximately 30A with a fan blowing across the board. In that configuration, the temperature stayed around 45°C (Ambient 28°C) showing that even modest airflow significantly improves cooling. Unfortunately, I couldn't continue that test for longer than 1h because my improvised load bank failed rather dramatically and ended the experiment.
Overall, I'm very happy with the results. The hardware appears to comfortably handle the target current, and the thermal performance is in line with expectations.
Based on these results, I would expect the board to operate comfortably in the 20–25A range without forced cooling when installed in a large enclosure with good ventilation. For installations in smaller or sealed enclosures, or where ambient temperatures may be elevated, I would recommend fitting a fan to provide additional thermal margin.