Never heard of the tool, but by the sound of it, it extends your battery life by letting you not charge to 100% (e.g. only charge to 80%).

That's real. Doing that will prolong the life of your battery.

Should you pay $25 for a tool that will do that? Well, if you're on Android 12 (edit: and your device manufacturer has implemented it), there may be an option in the battery settings to limit charging to 85% which gives you most of the benefit.

If you're not on Android 12 but have a rooted phone, you can get a free app that does the same thing.

If protecting the battery is important to you, you don't have a rooted phone (and don't want to root it), and don't have Android 12, then as far as I can tell from reviews, Chargie does do what it says.

I use Advanced charging controller to set charge rate and capacity thresholds. Limiting both (but especially capacity) will absolutely extend the service life of the battery. I limit it to 60% in normal use, which extends service life greatly and also have presets for 80% and 100%.

ACC requires root access. This device accomplishes the same goal without it using external hardware.

Hard to say. I thought most modern Android phones have charge management in software now.

I'm very reluctant to plug my phone into random USB-C devices though, you just don't know what's on these things.

If your phone can't do charge control on it's own, Chargie is totally legit: I have 8 of them - As and Cs - and they work great.

Snakeoil.

The fact that some people are saying "maybe" or "it might" means there is enough uncertainty out there to get a few suckers to buy this shit.

Got one when I got my Samsung Fold 3. I liked smart charging on my old OnePlus but Samsung doesn't have that.. Only way is to limit it to 85% or charge to full 100%. And I rather use full 100% of my battery because I use it a lot.

Last time I checked my battery health was still "good" after 2 years of use (via Samsung diagnostic tool).

I've set my chargie charge to 85% and then recharge only when battery drops 10% or more. And at 5:00 it charges once to 100% so I have my full battery at morning

Couple of times in last two years it hasn't charged up to 100% (stopped to 85%). Don't know why, but it hasn't been huge issue.

Don't know if charge helps with battery, but at least it doesn't make it worse 🤷