A technician drives ninety minutes to a site, diagnoses a failed connector in four minutes, and drives back because the replacement is in a warehouse in another city. That is the most expensive possible outcome of a correct diagnosis, and it is entirely a stocking decision.
What actually fails
Ranked by frequency across a mixed AC and DC fleet, the failures that generate visits are consistent and mostly mechanical.
| Part | Why it fails | Stock level |
|---|---|---|
| Type 2 cable and connector | Driven over, dropped, pulled | One per ten AC units |
| CCS2 cable assembly | Same, plus thermal cycling | One per fifteen DC units |
| Holster / cable retainer | Broken off by drivers | Generously — they are cheap |
| RFID reader module | Water and static | One per twenty units |
| Router / SIM module | Heat, power cycling | Two per depot, always |
| Contactor | Wear from switching cycles | One per DC model in service |
| Display / touch panel | Sun and vandalism | One per model |
Note what is not on the list. Power modules and control boards fail too, but rarely enough — and expensively enough — that stocking them is usually the wrong call unless you run a large single-model fleet.
The depot rule
Spares belong where the technician starts their day, not where procurement finds it convenient to store them. A part in a central warehouse that requires a courier is functionally not stocked — the visit still fails, it just fails with better paperwork.
Track consumption, not just stock
The consumption rate per part per model is the number that tells you something. A connector replacement rate that is triple the fleet average on one model is a procurement finding. The same rate concentrated at one site is a site finding — usually a kerb the cable is being dragged over, or a bay layout that makes drivers stretch the cable.
Both are fixable. Neither is visible if replacements are recorded as "connector, one" against a cost centre rather than against a station and a model.
The warranty question
Many of these parts are under warranty for the first year or two, which tempts operators into waiting for a vendor replacement rather than fitting one from stock. Fit from stock, then claim. The charger earns while the claim is processed, and the claim is easier to make with the failed part in hand and the session records showing exactly when it stopped working.