If you’ve ever prepped a medical device for a regulatory review, such as an FDA 510K submission, you’ve probably hit that moment where you ask yourself: “Wait—why do we have to run the EMC tests, called out in IEC 60601-1-2, AIM 7351731, and/or the Common EM Emitters tests in both AC charging and battery mode if the thing doesn’t even do anything while it’s charging?”
It’s a fair question. After all, if your wearable medical ring is off your finger, sitting peacefully on its charger, and minding its own business… what’s the big deal?
Let’s just say the regulators, like the FDA, want to make sure that “peaceful charging” doesn’t secretly turn into “silent frying.”
Electromagnetic Compatibility: When the Invisible Gets Real
EMC testing is like throwing a medical device into a storm of invisible chaos—cell phones, Wi-Fi, MRI machines, that ancient coffee maker humming in the hospital break room. The goal? To make sure the device stays cool, calm, and collected—no matter what electromagnetic madness it’s surrounded by.
Now, even though you may not use the device while charging, it’s still plugged in. And anytime you plug something in, you invite all sorts of electrical shenanigans into your circuit party. That’s why regulators (like the FDA and others) want proof that your device can handle itself gracefully—not just when it’s helping patients, but also when it’s sipping electrons from the wall.
The Charging Test: What Actually Happens
During testing, the device is connected to its charger and blasted with electromagnetic interference from every direction. Here’s what’s being checked:
- No overcharging: because spontaneous battery puffing is not a good look.
- No charging at the wrong voltage: devices don’t enjoy energy drinks.
- No failed charging: because “low battery” shouldn’t be the result of science.
- No hidden internal damage: it should work perfectly fine after the test, no surprises.
The important part: the device doesn’t need to do anything special while charging. It just needs to keep charging and, afterward, power up like nothing happened.
So What’s the Real Point?
The whole exercise isn’t about proving the device works during charging—it’s about proving that charging doesn’t mess it up. Think of it as checking that your phone doesn’t melt when you plug it in overnight. Regulatory bodies just, like the FDA, want assurance that after all that electromagnetic chaos, your medical device still wakes up in the morning, ready to save lives (or at least monitor vitals).
In Real Life
We’ve helped plenty of clients through this “why test the charger?” moment—everyone from wearable developers to implantable device teams. Once they understand that it’s about post-charging safety and reliability, it clicks (and the frustration level drops about 40%).
It’s not about the charger doing anything magical—it’s about making sure nothing bad happens while it’s doing its very boring, very important job.
The Bottom Line
Testing in both AC and battery modes isn’t overkill—it’s smart insurance. It keeps devices safe, regulators like the FDA happy, and your engineering team off the 2 a.m. panic email chain.
At F2 Labs, we make this process less confusing (and, dare we say, occasionally fun). If you’ve got a device and looming EMC testing, let’s talk before your coffee budget triples. We’re here to help. Contact Us Today.