At the recently concluded PRAWAAS 5.0 SUN Mobility has unveiled a modular multi-battery swapping solution for electric buses demonstrated on the Tata Starbus EV platform. Certified under AIS-038, this model has two battery modules that can be swapped simultaneously, with the entire process completed in under five minutes. The system supports both 50 kWh and 100 kWh battery configurations.
Speaking to this publication, Ashok Agarwal, CEO, SUN Mobility HEV, said, the company has received more than 500 inquiries for the new swappable solution. For a company that has been quietly working to solve one of the biggest problems holding back electric commercial vehicles in India, that response says everything.
The problem is that an electric bus or truck today costs more than twice the price of an equivalent diesel vehicle. Finance it over four or five years and the cash flows simply do not work. Add to that the burden of setting up charging infrastructure, managing battery health, and trying to sell the vehicle second-hand when no one knows how to value an ageing battery — and it becomes clear why fleet operators have been slow to switch, he said.
Battery swapping addresses all of these problems at once, he said, adding that instead of charging the vehicle, swap the depleted battery for a fully charged one at a swapping station. The process takes less than three minutes for a single battery. “The operator buys the bus — from any CV OEM brand, but does not buy the battery. The battery is provided on a pay-as-you-go basis, in what the company calls energy as a service. The risk of battery degradation, technology change, and replacement sits with the swapping company, not the operator. With the battery removed from the equation, the cost of the vehicle drops to levels comparable with diesel, or even lesser. Financing over four or five years becomes viable again. Second-hand valuation becomes straightforward because the battery is not part of the vehicle. And since swapping takes minutes rather than hours, a bus or truck can run almost around the clock, significantly improving asset utilisation,” Mr. Agarwal explained.
Technology Built for Flexibility
Under the swappable solutions, the batteries come in four sizes — 25 and 50 kWh for 330-volt vehicles, and 50 and 100 kWh for 650-volt vehicles. The swapping stations are OEM-agnostic, voltage-agnostic, and battery chemistry-agnostic — it does not matter whether an operator uses LFP or NMC cells. The system works with commercial vehicles ranging from three tonnes all the way to 55 tonnes.
“The modularity is what makes it genuinely versatile. A single 12-metre bus platform can serve four different applications — school bus, staff transport, intra-city, and city transport — simply by swapping in a different battery size for each duty cycle. At Tata Motors’ Sanand plant, we are already solving a real-world problem; 16 staff transport routes of varying distances, each requiring a different battery capacity. The same bus, the same platform, the same swapping stations — just different batteries for different routes.
For intercity travel, the case is equally compelling. A bus travelling from Jaipur to Delhi would stop at a swapping station midway — roughly where the driver would take a break anyway — swap the battery in minutes, and continue. Range anxiety, in this model, simply does not exist. You can take this bus from Salem to Ludhiana or Jaisalmer to Guwahati. It does not matter,” he highlighted.
The rollout strategy, according to him, is measured and deliberate. Rather than trying to build open highway infrastructure from day one, the company is starting with closed-loop applications — cement plants, FMCG logistics, mining, and steel — where routes are fixed, distances are known, and utilisation can be assured. Operators commit to eight to ten year contracts, giving the company the revenue certainty it needs to invest in infrastructure. Open highway corridors will follow organically as closed-loop customers on different parts of the same route gradually connect the dots, he signed off.
