Hyundai Ioniq 5 May Overheat When AC Charging and the Fix Isn't to Everyone's Liking

It looks like Hyundai cannot catch a break. After the "Kia Boyz" TikTok trend, the motive power loss allegations, and the Theta II engine problems, the E-GMP-based Ioniq 5 has its fair share of issues that are close to being dangerous. It is unfortunate because the South Korean automaker is enjoying some decent success with the sales of this unit.

Multiple owners from North America have reported that their all-electric crossovers start to overheat when plugged in at home. The Ioniq 5 can replenish its energy storage unit at a maximum power of 11 kW when it's extracting electrons from the grid via a 48-amp EV charger. However, it seems that a seemingly widespread issue is not allowing some of these vehicles to take full advantage of their enhanced charging capabilities.

When the plug is inserted into the EV's inlet, the port's temperature rises as soon as charging begins. With an outside temperature of 80 degrees Fahrenheit (27 degrees Celsius), the inlet's temperature sits at around 100 degrees Fahrenheit (38 degrees Celsius) before sucking in electrons at 11 kW per hour. But after only 38 minutes, the port's temperature more than doubles, reaching 210 degrees Fahrenheit (99 degrees Celsius). Three minutes later, the charging fails.

Now that outside temperatures have risen across the United States, more Ioniq 5 owners complain about dealing with the same issue. They can't charge these Hyundai EVs for more than half an hour at 48A without having the car's inlet overheat.

Some have escalated the issue and submitted complaints to the National Highway Traffic Safety Administration (NHTSA). But this is hardly a safety issue because the car does not allow the inlet to overheat until it catches fire. It disengages the charging when temperatures are too high.

But this problem is not something new that's just now being noticed. In April, Hyundai released a Technical Service Bulletin (TSB) that also applies to E-GMP-based Kia units. The optional fix is to drop the charging speed from 48A/11 kW to half or less, so the charging can continue until the desired battery charge level is reached. If you're among the affected owners, print out the TSB below and show it to Hyundai's technicians when the car is scheduled for a service visit. They'll make the necessary updates.

Another possible fix for owners dealing with this issue is setting the amperage to 32A instead of 48A. The charging will drop from 11kW an hour to around 7kW per hour, which is more than enough to fill the battery to 100% in approximately 11 hours.

Finally, Ioniq 5 and Kia EV6 owners would like a better outcome. Most of them claim that Hyundai needs to advertise the charging speeds correctly and offer a proper fix that allows those with Level 2 home chargers to take full advantage of their installation.

If the automakers want to provide the buyers with a real solution, they should offer affected customers the option to replace the port and/or the charging harness. But the overheating issue might require more than just new parts, which could cause quite a dent in the brands' budgets.