AC vs DC Charging Feasibility and Charger Mix
Dwell time decides this, and almost nothing else does. Every other consideration is a constraint on executing the choice dwell has already made.
Where vehicles sit for hours, AC delivers more energy per unit of capital and per kilowatt of connection. Where they sit for minutes, AC delivers almost nothing regardless of rating, and only DC is useful.
Test a site against dwellFor Site owner, CPO, consultant
The difference that matters
AC charging passes alternating current to the vehicle, which converts it using its own onboard charger. That converter is small, so the rate is modest and capped by the vehicle. DC charging does the conversion in the unit and feeds the battery directly, which is why it is faster, larger, more expensive and far more demanding of supply.
Match to dwell
Swipe to compare
| Dwell | Typical site | Choice |
|---|---|---|
| Overnight | Home, apartment, depot | AC |
| Full working day | Workplace, airport long stay | AC |
| Two to four hours | Retail, hotel, restaurant | AC, higher rating |
| Thirty to ninety minutes | Mall, cinema, service | AC or DC, depends on turnover |
| Under thirty minutes | Highway, transit, forecourt | DC only |
The supply consequence
A DC bay demands far more supply capacity than an AC bay, which is why DC frequently triggers the connection upgrade that dominates a site budget. On a constrained supply, the same connection that serves one or two DC bays may serve many AC bays.
That is the trade to evaluate: fewer fast bays or more slow ones, on the connection you actually have.
The utilisation consequence
DC carries much higher capital, so it needs throughput to justify it. An underused DC bay is an expensive asset earning nothing. AC tolerates low utilisation far better, which is why destination and workplace sites are frequently viable where a fast-charging installation at the same location would not be.
Most sites want a mix
Locations with more than one dwell pattern, which is most commercial sites, are served best by a mix. A retail site with staff parking all day and customers for an hour has two problems, and one charger type solves only one of them.
The ratio comes from the dwell distribution rather than from a rule of thumb.
Our position
RIOD's platform and engineering focus are AC charging, so treat any AC recommendation from us with that in mind. The dwell test above is the one to apply, and where it points at DC, it points at DC.
Where we think this is going
Our position, and it is not the fashionable one: the future of charging in India is slow chargers at maximum availability, not fast chargers at maximum power.
Fast charging photographs well and sells conference tickets. What we see in operation is that the useful metric is not how quickly a car can be filled but how reliably it can be plugged in at the place it was going to be parked anyway. A 7.4 kW unit that is free when the driver arrives beats a 60 kW unit that is occupied, out of service, or twenty minutes away.
Cars sit still for most of their lives. Charging that uses those hours needs less power per point, less supply reinforcement, less civil work and less capital, which is also why more points get built. That is the direction we are betting on, in India and generally.
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Test a site against dwellTechnically reviewed by Anees P K, Director of Technology. Last reviewed 2026-08-29.
Frequently asked questions
Which is better, AC or DC?
Neither. Dwell time decides it. Hours favour AC decisively on capital and supply; minutes require DC. Applying the wrong one is the most expensive site mistake.
Why is DC so much more expensive?
The conversion happens in the unit rather than in the vehicle, which makes it larger and more complex, and it demands far more supply capacity, frequently triggering a connection upgrade.
Can we start with AC and add DC later?
Often yes, provided the supply and civil design anticipate it. Retrofitting DC into a site designed only for AC can mean revisiting the connection.
What ratio of AC to DC?
From the dwell distribution at your site rather than a rule of thumb. Sites with two dwell patterns usually need both.
Is RIOD biased toward AC?
Yes, and it is stated. Our platform and engineering focus are AC. Apply the dwell test, and where it points at DC, follow it.
Test a site against dwell
Tell us who parks there and for how long, and we will tell you which technology the site actually needs.
Test a site against dwell