Why This 2025 Hyundai Ioniq 5 Wants A New Battery: P1AA700 Situation Defined

I prefer to remind those that they actually don’t have to fret about their electric-vehicle batteries.

The huge, overwhelming majority of all batteries survive till the automotive is crashed, mechanically totaled or travels over 300,000 miles. A small subset has insufficient cooling or unhealthy battery administration and degrades by that time. And some have manufacturing defects, which just about at all times would require in-warranty replacements.

File this Hyundai Ioniq 5 in that final class. A small subset of early-production 2025 Ioniq 5s—the primary fashions inbuilt North America, with the North American Charging System (NACS) plugs—”might expertise a charging subject the place a voltage distinction between battery cells prevents the Excessive Voltage Battery from totally charging,” a technical service bulletin filed with the Nationwide Freeway Site visitors Administration reads.

The answer: Substitute the battery. However if you wish to see what the expertise of a rising battery voltage differential seems like, watch the video beneath from The Ioniq Man. Founder Corbin runs top-of-the-line channels for Hyundai points, partly as a result of he is presently on his third Ioniq car, and second Ioniq 5.

On a current vacation street journey, his 2025 Ioniq 5 stopped hitting its peak charging fee, and struggled to take care of its cost curve. Corbin instantly flagged this. He’s, in spite of everything, the form of EV nerd (like me) that follows his personal charging curve on numerous machines to trace the automotive’s efficiency. What he noticed was regarding, and persevered at quite a lot of totally different charging stations.

His charging velocity continued to decelerate till, finally, the automotive couldn’t quick cost in any respect. Degree 2 charging labored till, finally, the battery died.

And figuring out what we do about voltage differential, this tracks. Electrical automotive battery packs are made up of tons of of cells, and so they all have to be charged and discharged equally. Battery packs aren’t steady when cells are imbalanced, which may result in harmful situations, so the automotive’s “battery administration system” (BMS) screens cell voltages and retains all the things equally charged. However when the logic of the BMS fails or a cell has a charging or discharging subject, that voltage differential will initially decelerate the utmost charging velocity till the imbalance grows, at which level the automotive will set off a fault code and shut iself down.

Corbin’s automotive issued a P1AA700 fault code—a generic troubleshooting code that may be learn by an OBD2 code reader—for a Cell Voltage Deviation. Hyundai rapidly acknowledged this because the telltale signal of a voltage-differential failure and ordered a substitute battery for the Ioniq 5. (He additionally had a terrific explainer video on the P1AA700 subject earlier than his personal private expertise.)

In an electronic mail to InsideEVs, Corbin confirmed that the corporate fast-tracked him a battery. However the coolant refill course of might not have been carried out appropriately, resulting in a low-coolant subject shortly after he obtained the car. He’ll have a full replace on the saga someday quickly.

It is absolutely a irritating expertise. However understanding the mechanics of a battery failure additionally helps demystify the know-how. This isn’t rocket science. A cell should reliably cost and discharge at a predictable fee. A BMS should monitor for cost imbalances and rebalance them. The cooling system should maintain the system at a protected and environment friendly temperature. So long as these elements all do their job, batteries can simply final for tons of of hundreds of miles.

However here is one of the best bit: They’re all additionally assured for eight years or 100,000 miles. Any manufacturing high quality subject with the battery cells or fault in BMS logic is prone to manifest throughout the first 100,000 miles of a automotive’s life, so most failures result in in-warranty substitute. And trendy EV batteries simply do not fail fairly often.

Level is: You actually should not fear about it.

Contact the creator: Mack.Hogan@insideevs.com.