Victron SmartSolar MPPT 150/45 overheating in locker

Problem

Our Victron SmartSolar MPPT 150/45 started reducing charging current during hot afternoons. Instead of producing ~30A it dropped to around 10–15A.

Fix

1. 1

   At first I thought something was wrong with the solar panels.

2. 2

   But panel voltage looked completely normal.

3. 3

   Then I noticed the MPPT was installed inside a very tight electrical locker with almost no airflow. I added a small ventilation hole and moved some cables away from the heat sink. After that the controller stayed cooler and charging current went back to normal. Apparently the MPPT will reduce output if it gets too hot to protect itself.