Dear community,
luckily this is all that happened, but could have been worse. To avoid the same in the future, let me know if I did anything wrong:
- Operated outside, but in dry box (worked for weeks)
- Connected to a new 12V 384Ah LiFePO4 battery
- Used to power a Raspberry Pi Zero 2W
- Outside temperature approx 30° Celsius
Wiring cannot be an issue, as it worked for some time.
What component got too hot here? Does anyone have a explanation? Is it possible to have it replaced in such case?
Thanks for any help on this!
From the photo, the damaged component appears to be R15. This is the 0.05Ω current-sense resistor in the load current path, between GND and CATHODE. It is used to measure the actual output/load current.
This part should not get hot under normal operation. At the rated 3A output current, its dissipation is only about:
3A × 3A × 0.05Ω = 0.45W
So the damage shown in the photo does not look like normal overheating caused by 30°C ambient temperature or by powering a Raspberry Pi Zero 2W. It indicates that an abnormally high current has flowed through the load path, most likely due to a short circuit or fault on the output/load side.
Also, the fact that the setup worked for weeks does not rule out a wiring or installation issue. Outdoor installations can develop intermittent faults over time, for example due to condensation, corrosion, insects, dust, loose wires, damaged insulation, cable movement, conductive debris etc.
A 12V 384Ah LiFePO4 battery can deliver a very large fault current. If there is no fuse or current limiter close to the battery, a short circuit can damage the board before anything else limits the current.
Replacing R15 alone may not be reliable, because the PCB around it appears to be heat-damaged/carbonized.
Is it possible to have it replaced in such case?
Please be reminded that we do not discuss non-technical question here, as stated in the forum rules.