How we earned the Guinness World Records title for Longest EV Run on a single charge

We recount the 949.0km record run set between Bengaluru and Navi Mumbai in the Mercedes EQS.

Published On Nov 23, 2024 08:00:00 AM

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Longest journey by an EV on a single charge

There are some things we just can’t resist at Autocar India: the opportunity to drive a blisteringly fast car, the lure of the open road, and the hunt for the fastest lap time around a race track, to name a few. But if history is anything to go by, you know that there’s one opportunity we jump at faster than a predator lunges at its prey – setting a new world record. Or, in this case, to beat one and raise the bar for anyone attempting it in the future. And that’s exactly what we did. By covering 949.0km on a single charge, we motored past the previous record of 916.74km – set in the UK in a Ford Mustang Mach-E – by a fair margin of 32.26km.

The seed of the idea was planted when we first drove the EQS 580 back in 2022. The ARAI-claimed range of 857km from a massive 107.8kWh battery was, and still, remains the highest for an EV in the country. Needless to say, we were awestruck by the figure. Even more impressive, though, was the EQS’ drag coefficient of just 0.2, making it the most aerodynamically efficient car in India. Once you’ve digested that fact, it’s easy to see how this was a record just begging to be set. So, you can see why this was a calling we just couldn’t resist.

Taking the high road

The one thing that takes precedence over everything else when trying to set a world record is preparation. And that means ensuring that the car, driver and road are all carefully considered. Right from the start, we were clear that we didn’t just want to beat the existing record in some controlled conditions but do it on a road that represented real-world Indian conditions, while also being of great significance to the nation.

The monsoons added to the drama, forcing us to use the wipers and adding rolling resistance, too.

That’s how we settled on the Bengaluru-Mumbai highway, NH 48, as the trajectory the EQS would take. Part of India’s celebrated Golden Quadrilateral, this road would let us prove that not only could the EQS 580 outdo itself in everyday conditions but that our road tester and the man behind the wheel, Rahul Kakar, was an equally formidable factor in the success of the attempt. Adding a layer of uncertainty to the run was the fact that we undertook this drive at the peak of the Indian monsoons, which would mean using the wipers more often, dealing with potential waterlogging and standing water that would use up more energy getting through. Small amounts, no doubt, but when you are trying to stretch the range to such high levels, every drop or watt counts.

The chaos of India’s highways added yet another range-sapping challenge to the drive.

And then there’s the worsening road conditions, compounded even more by the stretches of ongoing road repairs, which meant multiple diversions and even more kilometres of uncertainty. World records aren’t meant to be easy, but even by that standard, this was a challenge that had us equal parts excited and understandably, unsure and very nervous.

Man, machine and mayhem

It was 4am on September 3 as man and machine gathered outside the Mercedes-Benz showroom in Bengaluru. The air was crisp, the city was silent, but the level of excitement was palpable. Engineers from Mercedes performed final checks on the car, ensuring everything was in order. Rahul got the log book ready and performed his final stretches, fully aware that the next 10-odd hours would push his focus and endurance levels to breaking point. The fully charged EQS was unplugged, the charging port was sealed, witness signatures were added, and the team got the go-ahead. Everything was in place to begin what would be an arduous two days on the road.

The charging port was sealed and signed by witnesses before the record run.

Before we share how the drive panned out, though, we must tell you about Rahul Kakar. He has been behind the wheel for Autocar India’s most ambitious projects over the years. His affable personality betrays the many avatars he’s capable of morphing into; from an angry young man tearing up the track behind the wheel of a supercar to a bring-it-on off-road expert with the technical know-how to back up some serious skill. He’s always been the first one to volunteer for challenges the rest of us are, occasionally, apprehensive about. On this drive, however, it was time to tap into his monk-like levels of patience and resist the temptation to unleash the 523hp and 855Nm of torque on offer in the EQS 580. After all, what lay ahead was two long days of driving in the most calm and composed manner he could pull off, all while keeping an eagle eye on the energy consumption figures and recalibrating his driving style to ensure the target was met.

Witnesses Asokan S from SLS automotive consulting and Ashish Samant from Zen Micro Systems flag off the drive.

Finally, all checks complete, the flags were waved and off we set. No squealing tyres and instant torque, though. This was a gentle departure, with no more than 5 percent of accelerator input on the instrument cluster, and foot, as light as a feather, on the pedal. And this wasn’t just to get rolling. This was how we had decided to drive for the entirety of the journey, our minds now razor-sharp mathematical tools that couldn’t waste even 1 percent of charge on driving outside the optimum window of efficiency. The initial leg of the drive was smooth sailing, with early morning traffic at a bare minimum, mildly offset by the fact that the car’s headlights had to be switched on until the sun came up. Yes, that’s how fine the margins were.

Leaving early meant using energy on headlights but a lot of free coasting.

Once out on the open highway, we found the efficiency sweet spot of the EQS between 50-60kph, and that’s where we kept the speedo for as much of the drive as we could. That was, until, the heavens opened up a couple of hundred kilometres before the first planned stop at Belagavi. Here’s the thing about hypermiling: you always want to be on the path of least resistance. And pouring rain doesn’t exactly favour that. With the possibility of encountering standing pools of water that add to the rolling resistance and compromise range, all we could do was cross our fingers and just keep rolling with the punches.

Setting up the EQS for maximum range meant sacrificing some creature comforts.

As the battery’s state-of-charge (SoC) dropped every few kilometres, Rahul’s state-of-anxiety climbed at a directly proportional rate, as did the traffic we encountered. At the 50 percent SoC mark, we had managed to cover around 470km, with the car’s computers displaying 475km as the remaining range. As we rolled into Belagavi for the night, 515.2km under our belt and 44 percent charge remaining, spirits were high. The math was on our side. At this rate, we’d surely beat the target of 916.74km. But what we didn’t know, and wouldn’t find out until the next day, was the mayhem that lay ahead.

Against all odds

The next morning, driver and support crew well rested, we set off for the final push into Mumbai. We had been warned about roadworks along the way, but nothing could prepare us for the utter pandemonium that followed. Between Belagavi and Karad – a nearly 200km-long stretch – diversion after diversion meant traffic would slow to a crawl every few kilometres. If that wasn’t bad enough, the road conditions along the diversions were as close to the lunar surface as one can experience back here on Earth. This meant adjusting the driving style but also, importantly, the regen modes.

Roadworks and diversions added complexity to the drive.

Throughout the drive, Rahul had been toying with the EQS’ three levels of regenerative braking according to the terrain we were on. The strongest setting on long gradual downhill slopes, recovering as much energy as possible back into the battery, the lower setting on shorter slopes, and completely turned off on flat stretches so that he could lift and coast, letting the car roll forward freely without expending any energy. This bit of situational awareness is what paid dividends during the Belagavi-Karad stretch of what was a highway from hell.

A puncture in the closing stages of the drive failed to dampen our spirits.

Finally, past the roadworks, we were back in the hunt for the 916.74km target. Even with occasional spells of rain threatening to play spoilsport and heavy traffic making our target speed impossible to maintain, we rolled on towards Mumbai. That is, until, disaster struck in the form of a puncture on the rear left tyre. Unwilling to let this setback dampen our spirits, we rolled up our sleeves, replaced the tyre, and gently rejoined the flow of traffic headed towards Pune.

The home stretch

If you thought, as we did, that things would get easier on familiar territory between Pune and Mumbai, oh boy, are you in for a surprise! We rolled past the Talegaon toll plaza, crossing the 884km mark – 32.74km shy of our target – with just 4 percent SoC remaining. But even with the aircon turned off and windows rolled up, we didn’t break into a sweat just yet. Because ahead of us was a steep downhill ghat, a blessing for extending the range of an EV. Regen mode set to max, the SoC fluctuated between 1 percent and 3 percent all the way to the bottom.

One eye on the cluster to ensure we didn’t exceed 5 percent accelerator input.

And then came the moment we had all been waiting for with bated breath, the 916.74km mark was crossed. While this would have been an appropriate moment to rejoice, we resisted the urge to let our hair down and instead kept our hands on the wheel and eyes on the road, knowing full well that records are bound to be broken, and the only way to ensure this one wasn’t broken anytime soon was to build as large a margin as possible.

Reviewing the log book and filling out witness statements was all part of the process.

We pressed on right up until the SoC hit 0 percent, lighting up the dashboard like a Christmas tree with all sorts of warnings and instructions to pull over immediately and plug in, or risk losing drive to the wheels. Finally, at 949.0km on the dot, we were forced to pull over in Navi Mumbai and acknowledge that we had built a 32.26km margin to the previous record. It took a minute for it to sink in, and another minute for the adjudicator to verify that we had indeed achieved what we had set out to do. And then the penny dropped. We were now the proud holders of a GUINNESS WORLD RECORDS title! And the rest, as they say, is for the history books.

Rahul being handed over the certificate by the Guinness World Records adjudicator Rishi Nath.

Autocar India’s Head of Special Projects, on driving to break the World record:

“It’s a feeling I can’t quite describe. Frankly, even days after the record run, the gravity of achieving a world record is still sinking in. Staying focused was a real challenge, especially because driving at a sedate pace can quickly get monotonous. Music would have been a welcome distraction but that would’ve been counterproductive in this case. If I had to do this run all over again, I’d probably wait for the monsoons to subside. Maharashtra’s roads are challenging at the best of times, and the rains only made it that much more tricky. On second thought, though, the less-than-ideal conditions made it that much more rewarding too.”

Special thanks to MapMyIndia for equipping us with the GPS tracking device that was instrumental in verifying the record-breaking distance covered. Also thanks to SLS Consulting for providing us with technical observers.

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