Smartphones have advanced in so many ways over the past half decade—but battery life isn’t one of them. Most phones still need a daily charge, and the easiest way to accomplish this tiresome chore is to make it a part of your bedtime routine. The trouble is, my wife and I often go to bed at different times, and neither of us appreciates the sound of the other scrambling to find the charger or turning on the lamp to plug it in properly.

That’s why we want a good wireless charger—just a simple pad or stand you can place your phone on. Who cares if it takes longer to recharge if I’m sleeping?

Convinced that a couple of wireless chargers would take us a step nearer marital bliss, I started trying out products. That was about five years ago. We’ve tested more than 40 different wireless chargers since then, and we’re still looking.

3 Ways Wireless Chargers Fail

When I began my search, wireless chargers had single-coil designs that necessitated surgical placement. Put your phone down a half-inch off to one side, or bump the nightstand while climbing into bed, and you’ll wake up to a dead battery.

Thankfully, placement has become more forgiving as charging technology has improved and multi-coil designs have rolled out. But straying too far from the sweet spot or having a case on your phone can cause wireless chargers to generate a lot of heat, and heat is the enemy of a healthy battery. To combat this, many manufacturers include fans that make a tiny whirring sound.

The whir of a tiny fan is certainly irritating, but at least it serves a practical purpose. Unfortunately, many chargers also emit a high-pitched whine or buzzing sound. It’s the kind of noise you wouldn’t notice in a busy office but can drive you nuts in a dark bedroom. One of the first wireless chargers I tried also emitted a loud beep when the phone was fully charged—a “feature” that got it expelled from our bedroom at high velocity.

Sound isn’t the only problem. Your phone needs stability too. A good wireless charger should have some kind of grips, so it stays on the surface it sits on, and so it holds onto your phone. On some models, a slippery phone can slide itself off, and on others all it takes is a slight bump to send your phone clattering onto the nightstand, cruelly rousing your significant other from their blissful slumber.