Short answer: charging electric buses and trucks is a depot job, not a highway one. The vehicles return to the same yard every day, their batteries are many times the size of a car's, and their schedules decide everything: how many chargers, how big, and how much power the yard needs from the grid. For buses the size is set for you: the Ministry of Power's 2024 guidelines say e-bus depots must install chargers of at least 240 kW, which is our Nova 240, with two CCS2 guns and load sharing between them. Light electric trucks and small cargo vehicles are a different case, and a Navigator 30 or a Nova 60 often does. Size from the duty cycle, plan the power for the whole fleet on day one, and stagger the charging so the yard's peak stays inside its connection.
Start from the duty cycle, not the charger
For a car park, we ask which cars will come. For a depot, we ask four questions about the vehicles that already exist:
- How much energy does each vehicle use in a day? Kilometres driven times consumption per kilometre, from the maker's figure or, better, from the fleet's own telematics.
- How long does it stand in the yard, and when? Overnight for most city buses and delivery trucks; between shifts for some.
- How many come back at once? The evening return is the depot's rush hour.
- What can the vehicle take? Its DC limit and its connector, from the maker's specification.
Divide the day's energy by the hours the vehicle stands, and you have the average power it needs. Add the hours lost to plugging, queuing and taper, and you have the charger size. More often than not, depot vehicles that stand overnight need less charger per vehicle than people expect, and more grid connection for the yard as a whole than anyone budgeted.
Overnight, or top-up during the day
Depot charging fills the battery while the vehicle stands, usually overnight. It is the cheapest way to run a fleet: the chargers can be modest, the sessions are long and predictable, and in states with time-of-day tariffs, night-time power can be cheaper.
Opportunity charging tops up during the working day, at a terminus or between shifts. It lets a fleet run longer routes on smaller batteries, but it needs high-power chargers where the vehicles pause and a timetable that leaves room for the stop. Most Indian fleets start with depot charging and add a fast top-up point only where a route demands it.
Why the yard's power is the real project
Ten buses each drawing 120 kW is more than a megawatt at the moment they all plug in. No ordinary connection carries that. Beyond a handful of light vehicles, a depot is an HT connection with its own transformer, and the application to the DISCOM is the longest lead item in the project. See how much power a charging station can get.
Two decisions make the connection smaller and cheaper:
- Stagger the charging. Vehicles that stand for eight hours do not all need to charge in the first two. The charge point management software can start sessions in sequence or cap the site's total draw, so the yard's peak follows the connection, not the other way round.
- Plan for the whole fleet once. Size the transformer, the cable trenches and the plinths for the fleet you will have in three years, and install chargers as the vehicles arrive. A second HT application on the same yard repeats the whole wait.
What the rules say
The Ministry of Power's Guidelines for Installation and Operation of Electric Vehicle Charging Infrastructure, 2024 set two floors for heavy vehicles:
- E-bus depots "must install EV chargers with a minimum capacity of 240 kW".
- Public stations for trucks and buses must have "at least two EV chargers with a minimum capacity of 240 kW each".
For e-buses bought under the central PM E-DRIVE scheme, the scheme's notification lists a CCS2 DC charging inlet as a required part of the bus. Every Nova charges through CCS2.
Which charger for which vehicle
| Vehicle | Usual pattern | Where we would start |
|---|---|---|
| Small cargo vehicle, light electric truck | Back to base every evening | Navigator 30 or Nova 60, one gun per vehicle that charges at the same time |
| Intermediate electric truck, private yard | Overnight in the yard, sometimes a midday top-up | Nova 120, two vehicles per charger |
| City or intercity e-bus | Overnight in the depot, top-ups between trips | Nova 240, as the guidelines require, with charging staggered across the night |
| Public station for trucks and buses | Short stops on a route | Two Nova 240s at least, as the guidelines require |
These are starting points, not answers. Every row changes with the vehicle's battery, its DC limit and its timetable, which is why we start every depot with the fleet's own data.
What else a depot needs
- Space to manoeuvre. A bus needs to drive in and out of its bay forwards. Chargers go where the cable reaches the vehicle's socket without crossing a walkway.
- Protection. Bollards around every charger. A reversing truck finds the charger the yard forgot to protect.
- One dashboard for the fleet. The fleet manager needs every vehicle's session, energy and cost in one place, and an alert when a vehicle did not charge overnight. OCPP chargers report all of it to the management software.
- A plan for a dead charger. At 6 am a charger that failed at midnight is a bus that does not run. Keep one spare gun's worth of capacity, and watch the overnight alerts.
What we would not do
We would not size a depot from the vehicle brochure alone. Real kilometres, real dwell times and the evening return pattern change the answer more than any spec sheet. We would not let every vehicle start charging the moment it parks, and pay for a connection built for a peak that need not exist. And we would not order chargers before the transformer has a date.
Running or planning an electric fleet? Book a site study and bring your fleet's daily kilometres and yard hours. We will size the chargers and the connection from them.
Frequently asked questions
What size charger does an e-bus depot need in India?
At least 240 kW per charger. The Ministry of Power's 2024 charging guidelines say e-bus depots must install chargers with a minimum capacity of 240 kW.
What does a public charging station for trucks and buses need?
At least two chargers of 240 kW or more each, under the same guidelines.
Which connector do Indian e-buses use for DC charging?
CCS2. The PM E-DRIVE scheme lists a CCS2 DC charging inlet as a required part of the e-buses it supports.
Should a fleet charge overnight or during the day?
Most fleets start with overnight depot charging, which needs smaller chargers and can use cheaper night-time power where time-of-day tariffs apply. Daytime top-ups are added only where a route needs them.
Does a bus depot need an HT connection?
Almost always. Beyond a handful of light vehicles, a depot's load is far above any LT limit, so plan for an HT connection with your own transformer, sized for the whole fleet you expect.
