Startup Deep Dive : Ion Energy — built India’s largest BMS business, then sold it

Ion Energy built one of India’s largest battery management system businesses, with founder Akhil Aryan claiming over 30% of the country’s two- and three-wheeler BMS market at one point — and then the company sold that exact business away. In May 2022, the Mumbai startup agreed to hand a controlling stake in its hardware unit, Maxwell Energy Systems, to listed auto-components maker Endurance Technologies in a deal that could reach Rs 308 crore ($40 million, as reported at the time), and by May 2025 Endurance owned all of it.

That is not the story of a startup that failed. It is the story of a startup that built two different businesses inside one company — battery hardware and battery software — and concluded, with real money on the table, that only one of them was worth keeping for itself. What follows is what is actually on the public record about Ion Energy: its 2016 founding, the near decade of building and selling battery electronics, the Endurance transaction and its aftermath, and the leaner analytics business, now branded Altergo, that Aryan and co-founder Alexandre Collet kept.

Quick facts

What they do

Ion Energy is a Mumbai-founded company that builds technology to make lithium-ion batteries last longer and perform more predictably, selling mainly to electric-vehicle makers, battery-pack manufacturers and operators of large stationary energy-storage systems (StartupTalky; Forbes India, November 2021). For most of its life it did this two ways at once: a hardware and embedded-electronics business — battery management system boards that sit inside a battery pack and control charging, discharging and safety — sold under the brand Maxwell, and a cloud analytics layer, first called Edison Analytics and later renamed Altergo, that ingests data from those battery packs to predict degradation, flag faults and extend usable life (StartupTalky). Maxwell’s customers were chiefly two- and three-wheeler OEMs and battery-pack makers; Altergo’s customers have included EV fleet operators and energy-storage system owners such as Volvo and Zenobe, according to company and directory listings collected via Tracxn. Since the 2022 sale of majority control in Maxwell to Endurance Technologies, Ion Energy’s own retained business is the smaller, software-only Altergo analytics platform (Entrackr, May 2022).

The origin

Akhil Aryan was not an engineer by training — he studied finance at the University of Mumbai — and before starting Ion Energy he was chief product officer at Haptik, the conversational-AI company, where he says he helped grow the platform from around 100,000 to 1.5 million users ahead of its eventual $100 million acquisition by Reliance Jio (StartupTalky). The idea for Ion Energy did not come from inside that job. It came from Tesla. After the Model S launch in 2015, Aryan looked into converting his father’s car to run on electric power, and found that the battery alone would cost more than half of what the finished vehicle was worth (StartupTalky). That single, very ordinary piece of sticker shock became the founding insight: lithium-ion batteries were the most expensive and least understood part of any EV, and almost nobody outside a handful of global cell makers had built the software to actually manage and extend their working life.

Aryan incorporated Ion Energy in October 2016 in Mumbai (Forbes India, 2020) and began building battery management hardware and software from scratch, backed initially by his own savings and a 2017 angel round of undisclosed size from investors including Sushil Jiwarajka, the OMC Power chairman and Nippo Batteries founder, and Haptik’s own founders, Aakrit Vaish and Swapan Rajdev (Inc42). The company’s international footprint arrived early and somewhat by accident: in 2017 or 2018, depending on the account, Ion acquired Freemens SAS, an eight-year-old French battery-management-systems developer, bringing its founder, Alexandre Collet, on board as co-founder and chief technology officer and giving the young Indian startup an engineering base in Grenoble alongside Mumbai (Forbes India, 2020; Inc42).

The struggle years

Ion Energy’s early years were less a series of near-death events than a slow grind against two structural problems the company has spoken about candidly. The first was talent: India in 2016 and 2017 had very few engineers with hands-on battery-electronics experience, since the country barely had an EV industry to train them in, so Ion had to build its own internal training pipeline rather than hire ready-made expertise (Forbes India, November 2021). The second was market education — investors and even prospective customers needed convincing that battery intelligence software was worth paying for at all, at a time when India’s EV charging infrastructure and policy support were both immature (Forbes India, November 2021).

The deeper, more consequential struggle only became visible years later, in the shape of the business itself. By the early 2020s Ion Energy was running two fundamentally different companies under one roof: a capital- and working-capital-intensive hardware business selling battery management boards into a two-wheeler OEM market notorious for squeezing supplier margins, and a much lighter, higher-margin software subscription business layered on top of it. Industry research on the battery management system market describes exactly this tension — OEM customers hold significant pricing power over BMS vendors, and the sector’s economics increasingly split between low-cost, low-margin hardware suppliers and higher-value software and systems players (IMARC Group; Fortune Business Insights). Ion Energy’s own history through 2022 reads as a live example of a company being pulled toward that fork in the road rather than a single dramatic crisis.

The turning point

The moment Ion Energy’s trajectory visibly bends is 18 May 2022, when it signed a Share Subscription and Purchase Agreement to sell control of Maxwell Energy Systems, its BMS hardware subsidiary, to Endurance Technologies, an Aurangabad-based listed auto-components maker looking for its first dedicated EV product (Autocar Professional, May 2022; Entrackr, May 2022). Endurance paid Rs 135 crore (about $17.5 million) up front for a 51% stake, structured as a mix of primary investment and a secondary purchase from existing shareholders, with the remaining stake to be bought out in phases tied to Maxwell’s performance through to FY2027 — a deal that could total as much as Rs 308 crore, or $40 million, if every tranche was paid (Entrackr, May 2022; Autocar Professional, May 2022).

The numbers on each side of that transaction tell the real story. Going in, Maxwell had shipped more than 65,000 smart BMS units, supplied over 70 automotive OEMs and battery-pack makers across 15 countries including India, France, Spain and the US, and was sitting on an order book worth more than Rs 150 crore (Entrackr, May 2022). Its own management expected FY2023 revenue of roughly Rs 40 crore, about double the prior year (M&A Critique, May 2022) — respectable growth, but on a base still small enough that a single large customer relationship could make or break a quarter, precisely the kind of concentration risk a listed component maker with Rs 7,459 crore in group revenue could absorb far more comfortably than a startup could (M&A Critique, May 2022). Endurance, for its part, framed the deal plainly: “Maxwell’s BMS would be our first EV specific product,” said managing director Anurang Jain, as the group raced to catch up on vehicle electrification (Autocar Professional, May 2022). Ion Energy kept its equity stake in Maxwell during the phase-in period and, more importantly, kept full ownership of Altergo, its analytics software business, entirely outside the deal (Entrackr, May 2022).

That phase-in ran its course faster than the original five-year framework suggested. On 8 May 2025, Endurance disclosed that it had agreed to buy the remaining 38.5% of Maxwell for a further consideration of about Rs 7.5 crore, taking it from the 61.5% stake it had accumulated in tranches since 2022 to full, 100% ownership (MarketScreener, May 2025; JM Financial Services, May 2025). The battery hardware company Akhil Aryan founded no longer belongs to him at all.

The money behind it

Ion Energy’s funding shape is that of a lean, hardware-plus-software startup that raised modestly by Indian venture standards, then converted its hardware unit into cash through a strategic sale rather than a conventional exit.

• 2017 angel round: undisclosed amount from Sushil Jiwarajka (OMC Power chairman, Nippo Batteries founder) and Haptik founders Aakrit Vaish and Swapan Rajdev (Inc42)
• Pre-Series A — July 2021: $3.6 million led by Amazon’s Climate Pledge Fund — Amazon’s first India investment through that $2 billion sustainability fund — with participation from YourNest Venture Capital, Riso Capital and Venture Catalysts (Energy-Storage.News, July 2021)
• What Amazon changed: beyond capital, the round came as Ion said it had an order pipeline worth more than $15 million to fulfil, and the funding was earmarked to serve that pipeline and grow the SaaS side of the business (Energy-Storage.News, July 2021)
• Reported total funding: public trackers disagree — EnergyStartups.org lists $4.6 million raised to date, while a Crunchbase-based aggregation cited via Tracxn puts it as high as $6.16 million across four rounds; the gap likely reflects the undisclosed size of the 2017 angel round
• The Maxwell sale as a funding event: the 2022–2025 Endurance transaction, worth up to Rs 308 crore ($40 million) for the hardware unit alone, dwarfs every venture round the company disclosed, and effectively became Ion Energy’s largest capital event (Entrackr; Autocar Professional, May 2022; MarketScreener, May 2025)

How it makes money

Historically, Ion Energy earned money three ways, and each had a different margin profile.

• BMS hardware sales (Maxwell): selling battery management circuit boards and modules directly to OEMs and battery-pack assemblers — a unit-economics business where component costs, manufacturing and OEM price negotiation set a hard ceiling on margin (StartupTalky)
• Platform licensing: licensing Ion’s BMS firmware and reference designs to other manufacturers, which the company said could cut 2-3 years off a customer’s own in-house BMS development timeline (Inc42)
• Analytics subscription (Altergo, formerly Edison Analytics): a cloud SaaS product sold on subscription to track battery state-of-charge, predict degradation and validate warranty claims — the part of the business Ion Energy chose to keep in 2022 (StartupTalky; Entrackr)

The part people got wrong about this business, looking at it from outside, was assuming the hardware and the software were one business with one margin structure. They were not. Hardware revenue scales with unit shipments and is exposed to the same OEM bargaining power and price competition — from Indian and Chinese suppliers alike — that squeezes every automotive component maker (IMARC Group; Fortune Business Insights). Software subscription revenue, by contrast, scales with batteries under management rather than batteries shipped, carries near-zero marginal cost per additional customer once the platform exists, and does not require Ion to compete on landed component price at all. Selling Maxwell and keeping Altergo was, in effect, a bet that the analytics layer — not the circuit board — was where the durable margin actually sat.

The numbers

Ion Energy’s corporate history complicates a clean multi-year revenue table: the business that existed in 2021 split into two separate legal entities in 2022, and the hardware half is now wholly owned by Endurance Technologies. What is publicly available spans both sides of that split, and is presented here as such rather than stitched into a single, misleading trend line.

Sources: StartupTalky (2021 figure, company-stated); M&A Critique, May 2022 (FY2023 management projection at the time of the Endurance deal); TheCompanyCheck, compiled from regulatory filings (FY2025 Maxwell figure).

• Deployed scale, 2021: more than 25,000 BMS units in the field managing over 100MWh of batteries, across 60-plus customers in 12 countries (StartupTalky, July 2021)
• Analytics scale, 2021: Altergo (then still called Edison Analytics in some coverage) was managing over 700MWh of batteries across 75-plus customers in 15 countries around the time of the Amazon funding round (Energy-Storage.News, July 2021)
• Order book at the time of the Maxwell sale: more than Rs 150 crore, spanning customers in 15 countries (Entrackr, May 2022)
• Headcount: 53 employees around 2020 (Forbes India); Maxwell alone had grown to 115 employees by 31 March 2024 (TheCompanyCheck) — after which it operated fully inside Endurance rather than under Ion Energy

Where the money comes from

The split that matters most for Ion Energy is not geography — though the company has always sold internationally, from its earliest days shipping to a dozen countries out of Mumbai and Grenoble — it is the product-line split between hardware and software, because that is the split the company itself acted on in 2022.

• By product line (pre-2022): BMS hardware and platform-licensing revenue through Maxwell versus subscription analytics revenue through Altergo/Edison Analytics — the company never broke out the rupee split publicly, but chose to sell the former and keep the latter (Entrackr, May 2022)
• By customer type: Maxwell’s book leaned on two- and three-wheeler OEMs and battery-pack makers; Altergo’s customer list has included fleet operators and stationary-storage owners such as Volvo and Zenobe (Tracxn-compiled company data)
• By geography: operations spanning India and France from 2017 onward, with customers named across India, France, Germany, Austria, Poland, North America, South Africa and the UK by 2021 (StartupTalky, July 2021)
• The surprise: the hardware business — the one with the bigger order book, the larger headcount and the “India’s largest BMS company” bragging rights — is the one Ion Energy gave up first. The smaller, quieter analytics business is the one it kept

The risks

• OEM pricing power in hardware: the battery management system market is described by industry researchers as bifurcating into low-cost hardware suppliers and higher-value system integrators, with automotive OEMs holding significant bargaining power over component pricing — a dynamic that compresses hardware margins regardless of how much volume a supplier ships (IMARC Group; Fortune Business Insights). This is arguably the exact pressure that made selling Maxwell rational
• Policy dependence of the underlying EV market: both Maxwell’s former hardware business and Altergo’s analytics business earn money only if electric two- and three-wheelers keep selling in volume, and that volume has proven sensitive to subsidy policy — India’s FAME-II incentive scheme was withdrawn on 31 March 2024 and replaced by the lower-incentive PM E-DRIVE scheme, a change reported to have hit electric two-wheeler sales (Tribune India; Down To Earth)
• A cooling funding environment for Indian EV-adjacent startups: sector-wide venture funding into Indian EV companies fell by roughly 37% between 2022 and 2024 amid policy shifts and a sales slowdown (Business Standard, December 2024) — a harder backdrop for a small, software-focused company like the current Ion Energy/Altergo to raise growth capital in in future rounds

The takeaway

The lesson in Ion Energy’s history is not that hardware businesses are bad businesses — Maxwell grew its order book, its customer count and its revenue for years, and a listed auto-components maker paid real money to own all of it. The lesson is narrower and more useful: when a startup builds a capital-intensive, OEM-dependent hardware product bundled together with a lighter, subscription-based software layer, the two halves will eventually demand different amounts of capital, different growth strategies and different investors, and trying to run them as one business under one balance sheet indefinitely gets harder as both scale. Ion Energy’s founders resolved that tension by selling the part with more revenue and more headcount to a buyer built to run exactly that kind of business, and keeping the part with fewer people and thinner disclosure but, in their own judgment, the better economics. Any founder sitting on a hardware-plus-software bundle should treat that as a live decision to make deliberately, rather than a structural accident to discover only when a buyer comes asking which half they actually want.

Frequently asked questions

What does Ion Energy do today?

Ion Energy now operates primarily as Altergo, a cloud analytics platform that monitors and predicts the health of lithium-ion batteries in electric vehicles and stationary energy storage systems. Its former hardware business, the Maxwell battery management system unit, is now wholly owned by Endurance Technologies (Entrackr, May 2022; MarketScreener, May 2025).

Who founded Ion Energy?

Akhil Aryan founded Ion Energy in October 2016 in Mumbai. Alexandre Collet joined as co-founder and CTO after Ion acquired his French battery management firm, Freemens SAS (Forbes India, 2020).

Why did Ion Energy sell its battery management system business?

The company has not stated a single public reason, but the deal terms and industry context point to a hardware unit facing OEM pricing pressure and needing more capital to scale, sold to a listed auto-components maker, Endurance Technologies, that wanted its first dedicated EV product; Ion Energy kept its higher-margin analytics software business, Altergo, entirely outside the transaction (Entrackr; Autocar Professional, May 2022; IMARC Group).

How much funding has Ion Energy raised?

Disclosed rounds include an undisclosed 2017 angel round and a $3.6 million pre-Series A in July 2021 led by Amazon’s Climate Pledge Fund. Public trackers estimate total funding at $4.6 million to $6.16 million, with the range reflecting the undisclosed 2017 amount (Inc42; Energy-Storage.News, July 2021).

Is Maxwell Energy Systems still connected to Ion Energy?

No, not as of May 2025. Endurance Technologies completed the acquisition of the remaining 38.5% of Maxwell that month, taking its ownership to 100% and ending Ion Energy’s equity stake in the hardware business (MarketScreener, May 2025; JM Financial Services, May 2025).

Sources

Figures are as of September 2026. Currency converted at $1 ≈ ₹96.0 as of 18 September 2026 (Trading Economics).

• Forbes India, “Akhil Aryan: On a power trip” (30 Under 30 profile), 2020
• Forbes India, “EV: Ion Energy: Building the tech backbone for electric vehicles”, November 2021
• Inc42, “ION Energy Looks To Propel India’s EV Dreams With Battery Management Platform”
• StartupTalky, “ION Energy – Success Story | Founder | Wiki | Business Model | Revenue”
• Energy-Storage.News, “Amazon invests in ESS battery analytics startup ION Energy”, July 2021
• Entrackr, “Endurance Tech acquires ION Energy’s advance electronics unit for $40 Mn”, May 2022
• Autocar Professional, “Endurance to acquire ION Energy’s subsidiary”, May 2022
• M&A Critique (Mergers India), “Endurance takes the EV route with Maxwell’s acquisition”, May 2022
• TheCompanyCheck, “Maxwell Energy Systems Private Limited – FY 2025 Insights”, accessed September 2026
• MarketScreener, “Endurance Technologies Limited completed the acquisition of remaining 38.50% stake in Maxwell Energy Systems Pvt. Ltd.”, May 2025
• JM Financial Services, “Endurance Technologies hikes stake in subsidiary – Maxwell Energy Systems”, May 2025
• IMARC Group, “India Battery Management System Market Size & Growth”
• Fortune Business Insights, “Battery Management System [BMS] Market Size, Share”
• Tribune India, “Subsidy cut hits electric two-wheeler sales”
• Down To Earth, “Electric two-wheeler subsidy cut to hurt mass adoption of EVs”
• Business Standard, “EV funding in India drops 37% from 2022 to 2024 amid policy, sales slowdown”, December 2024
• Tracxn, company profiles for ION Energy, Altergo and Maxwell Energy Systems, accessed September 2026

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