FOCCCI supply, 9 to 16 V

You bought the OpenInverter car-side CCS board. You read the wiki. It said 9 to 24 V was fine. You have a small truck. The house electrical is 24 V, and the DC-DC is sitting at 27. You hook FOCCCI up, and the fuse goes. You replace the fuse. It goes again. You pull the board off the truck and try it on a lonely 12 V battery with four wires and a clean ground, and the fuse still dies.

Then you look at the board. U5 is cracked. That little part is a TVS, SMAJ16A. It is a 16 V protector. It starts conducting somewhere around 18 to 20 V, which is exactly what a 24 V truck looks like to a diode that was never invited to that party. The old wiki line was wrong. The people who wrote the board said so, out loud, on the thread, and they changed the wiki to 9 to 16 V.

The builder swapped U5, stayed at 16 V and under, and the lights came back. That is the whole repair they published. This page does not invent another voltage, and it does not tell you to swap some other chip.

FOCCCI is the car side of CCS. It is not a 24 V truck module. Give it a real 12 V rail that stays in 9 to 16 V, or you will be shopping for another U5, and maybe another board.

Sources

• https://openinverter.org/wiki/Foccci — 12 V pin: 9 to 16 V; U5 TVS SMAJ16A conducts 18–20 V
• https://openinverter.org/forum/viewtopic.php?t=7096 — uhi22: old “9 to 24 V” wiki was wrong; SMAJ16A is a 16 V part; builder swapped U5 and stayed ≤16 V