Editorials · Reviewer Insight
I love that the Galaxy Watch Ultra 2 lasts three days, but Samsung needs to fix charging
Samsung really needs to fix this.
This article may contain personal views and opinion from the author.
It takes how long to charge?! | Image by PhoneArena
I couldn't believe the rumors when I first heard them: Samsung was about to make a massive 35% jump in battery size on the Galaxy Watch Ultra 2.
The original Ultra already had a big battery at 600mAh (as big as the Apple Watch Ultra), but the second generation was about to jump to an 800mAh one.
Well, it turned out to be true, and Samsung even managed to cram that bigger battery into a thinner body.
Three days of battery life is great until you need three hours to recharge

Image by PhoneArena
Samsung's new Ultra watch charges frustratingly slowly.
I critiqued last year's Galaxy Watch 8 series for the same sin, but those were smaller watches with smaller batteries.
Now apply the same slow charging to that massive 800mAh battery, and you have a problem.
Here in the office, we ran a standard charging test using the Samsung black magnetic charging puck and connected it to a 25-watt Samsung charger.
Well, behold the results of our charging test: it took the Galaxy Watch Ultra 2 more than FOUR HOURS to fully charge!
Sorry, but that's just insane.
With a smartphone, you can brush that slow charging off with a typical excuse: "Well, you can charge it overnight." But this doesn't really apply to a smartwatch. Modern smartwatches are meant to be 24/7 devices — sleep trackers, recovery monitors, and health companions.
That's exactly why Apple and Google have both focused on bringing faster charging speeds. With the kind of suggested non-stop use, charging windows become harder to find. Here is a typical use pattern: wear the watch all day and night to track your activities and sleep, give it a quick 30-minute top-up in the morning, and have it back on your wrist tracking your vitals.
This just doesn't fly with the Galaxy Watch Ultra 2, though.
Here is how much charge you get back with the Ultra 2 compared to an Apple Watch Ultra 3 and Pixel Watch 4.
30-minute top-up:
- Galaxy Watch Ultra 2 — 18%
- Galaxy Watch 9 40mm — 26%
- Apple Watch Ultra 3 — 55% to 60%
- Apple Watch Series 11 46mm — 80%
- Google Pixel Watch 4 45mm — 80%
This is what disappointment looks like in a numerical form.
Samsung solved battery anxiety but introduced charging anxiety

Image by PhoneARena
So we have pretty much established that the ideal smartwatch experience revolves around short charging bursts.
A good smartwatch should be able to give you enough juice with a short, 15-minute charging session to track your sleep. A 30 minute charge should be a significant top-up. And most people, expect a full charge to happen in under an hour.
1-hour top-up:
- Galaxy Watch Ultra 2 — 30%
- Galaxy Watch 9 40mm — 48%
And here is how much battery you get after a full hour of charging on the Galaxy Watch Ultra 2 and Watch 9.
You can argue that a bigger battery requires more time to charge, and there is no going around physics, but… four hours for a full charge?!
A three-day battery is only truly liberating when the charging experience is equally flexible.
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