Seoul’s State Of Charge Restrictions On EVs In Parking Garages Make No Damn Sense

Here’s an insane question: If you were the mayor of a major city and an electric car caught fire in a local underground parking lot, how would you respond? Well, Seoul has recently found itself in that position, and the city’s responding by banning all EVs with a state of charge above 90 percent from entering parking garages. I’m sorry, what?

A Mercedes-Benz EQE electric sedan caught fire while parked in an underground garage in Seoul, damaging or destroying a reported 140 cars and evacuating residents of the building above the parking garage. This incident sparked such a national conversation that the CEO of Mercedes-Benz Korea met with residents of the affected building, and the government of Seoul has put new rules in place to try and keep everyone calm. As reported by newspaper Korea JoongAng Daily, here are those rules:

The city government earlier this month said that EVs will be advised to be charged at 90 percent or less to enter underground parking areas. As for public parking areas, an 80 percent charging limit will also be piloted at rapid chargers in the capital, with plans to extend this to private operators. Both rules are scheduled to take effect by the end of September.

This just doesn’t make sense. First of all, 100 percent on the dash doesn’t mean 100 percent as far as actual battery voltage goes. Every EV comes with battery buffers that prevent the state of charge from getting dangerously low or high, so 100 percent is still well within the safe operating range of the equipment.

Mercedes Benz Eqe 2023 Hd F526c2a31b6596a13adb700a92daf0c07f2edbe37

Secondly, 90 percent state of charge isn’t a universal standard, because many different types of EVs use different cells and cell arrays, ergo you’re looking at different stored chemical energy across the board. A base Hyundai Kona Electric’s 48.6 kWh battery pack will have a whole lot less total energy in it at 90 percent state of charge than a GMC Hummer EV’s 212.7 kWh battery pack.

Thirdly, established protocol for the safe transport and storage of loose lithium ion batteries generally requires far lower states of charge than Seoul’s 90 percent on the dash rule. For instance, the International Air Transport Association states that lithium ion batteries transported by themselves “must be shipped at a state of charge (SoC) not exceeding 30% of their rated capacity.” So why did Seoul set the limit at 90 percent?

2023 Eqe Sedan Gallery 002 Xl

I’m not the only one trying to reason with this legislation, because at least one energy expert seems equally perplexed over Seoul’s new rules. Citing the aforementioned battery buffers, Professor Yoon Won-sub of a battery research centre at Sungkyunkwan University, told Korea JoongAng Daily that “Excessive charging isn’t the governing factor with a fire,” adding that ““It seems a bit like a ‘witch hunt’ blocking EV owners with cars charged 90 percent from entering underground parking lots.”

Indeed, these new policies reek of desperation to do anything to try to keep the general public happy regardless of scientific soundness. There’s no proof that an electric car charged to 90 percent has a substantially lower risk of thermal runaway than one charged to 100 percent, assuming everything’s equal and that either neither or both battery packs are defective or damaged.

Eqe 350

You know what could help? Modern equipment both installed in structures and employed by emergency services, investing in further training on first responders, and a science-based information campaign for the general public. There are ways of saving face in the wake of such a thermal incident, but limiting EVs parked in garages to 90 percent state of charge or less ain’t it.

(Photo credits:

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