Every electric bus or truck fleet has to decide where and when its vehicles will charge. There are two main strategies, and most large fleets end up using both.
Depot charging
Vehicles charge at their base, usually overnight or between shifts, using many chargers of moderate to high power. The vehicle leaves each morning with a full or near-full battery.
- Strengths: simple operations, charging at cheaper off-peak times, and full control over the site.
- Requirements: enough battery capacity for the full day's duty, and space and grid capacity at the depot.
Opportunity charging
Vehicles top up during the day at terminals, layover points or customer sites, using high-power chargers for short periods.
- Strengths: smaller batteries are possible, vehicles can run longer duties, and range is extended without returning to base.
- Requirements: high-power chargers at the right places on the route, reliable access, and timetables with enough layover time.
| Depot charging | Opportunity charging | |
|---|---|---|
| Charger power | Moderate to high, many units | High, fewer units |
| Battery size | Larger | Can be smaller |
| Energy cost | Often lower, off-peak | Often higher, daytime |
| Operational risk | Low, if the depot is reliable | Depends on on-route chargers working |
| Best for | Predictable daily duties | Long duties and intensive routes |
India's 2024 charging guidelines specify charging equipment of at least 240 kW for e-bus depots, reflecting how much energy bus fleets need overnight.
Choosing the mix
Start with route data: daily distance, energy use per kilometre, layover times and depot dwell time. Model which vehicles can complete their duty on depot charging alone and where opportunity charging is needed. A combination often keeps batteries and grid connections smaller while protecting service.
How PxT can help
PxT Energies models fleet duty cycles and designs both depot and on-route charging, from 240 kW bus chargers to megawatt truck charging.