Galaxy Watch 9 Battery Test Roundup: Bigger Cell, Same One-Day Watch
Samsung enlarged the Galaxy Watch 9 battery by up to 20%, yet reviewers still report roughly a day. Here is what the tests show, what the price buys and who should buy the Watch 8.
Prepared by theSoftware Desk·how our desks work
A Galaxy Watch 9 buyer gets a bigger battery than last year's watch and, according to most reviewers, the same day of use. The 40mm model went from 325mAh to 390mAh. The 44mm model is at 445mAh, 10mAh more than the Watch 8. The watch still wants a charger every night.
What the testers measured
Android Authority, in a review published September 25, measured about 30 to 35 hours with the always-on display off and under an hour of workout tracking. On a heavy day, with three hours of DJing and 20,000 steps, it had 15% left after 24 hours. Charging took more than 90 minutes at about one percentage point per minute. The reviewer wrote: "The one improvement everyone wanted the most isn't among them."
GSMArena agrees without giving hours. It calls the battery "one of the weak points," at "sub-2 days," despite the larger capacity.
Two YouTube reviewers reached the same ceiling. NL Tech, testing the 40mm in August, reported a maximum of about a day and a half and more often a day plus a little, the same as the previous generation. NL Tech also pointed out that Samsung's own comparison table rates the watches at the same "up to 30 hours" as before, and that Samsung's briefing talked up CPU and GPU gains of 32% and 19% from the new Snapdragon Wear Elite chip, not battery life. The reviewer suspected the chip is power-hungry; that is a guess, and no source measured it.
Destiny Ihejirika went further and revised an earlier claim. After a factory reset, they retested the 40mm and said they could no longer stand behind two to three days. Their unit fell to 50% by 10:34 p.m. on the first day, was at 33% the next morning, and reached 25% around 10:20 a.m. The same video reported close to two hours for a full charge on that unit, and noted that a commenter had seen far faster charging, so unit variation may be real.
Against the Pixel Watch 5
How-To Geek wore a Galaxy Watch 9 and a Pixel Watch 5 on opposite wrists for a week. The Pixel stayed above 80% at 11:37 p.m. on every day, and the Samsung fell below 50% on one. The sizes were not identical (Samsung's 40mm at 390mAh against Google's 45mm at 465mAh), which tilts that comparison, and the 41mm Pixel Watch 5 (332mAh) carries the same endurance rating as the 40mm Galaxy. Even so, the writer picked the Galaxy Watch 9 for its thinness, about 4mm slimmer, and said Google had finally caught up to Samsung's software but not passed it.
What the software promise adds
GSMArena credits One UI Watch 9 as "one of the best takes on Wear OS on the market, with 5 years of software support," and lists native Gemini voice activation. The same review lists the catches: proprietary straps and charger, health features that need a Samsung phone, and a $30 or €30 price increase over the Watch 8. Android Authority gives US prices of $379.99 for 40mm and $409.99 for 44mm, with LTE adding $50.
Five years of updates is a long time to charge a watch every night. This desk's inference is that a cell which runs one day at launch will run less in year three; none of the sources tested aging or covered battery replacement for this watch.
Who should buy what
The sources split on the verdict but not on the evidence. Android Authority called it "a very good smartwatch" but said it could not "wholeheartedly recommend" it to someone who will "instantly feel let down by its battery experience." GSMArena recommended buying the older Watch 8 and saving the difference, because the new health features are "hardly...essential."
The buyer-advice reading follows from that: choose the Watch 9 if thin design and the Wear OS software matter and nightly charging is already routine. Otherwise, a discounted Watch 8 delivers largely the same day of use for less. Of the two sizes, the 44mm has the larger cell on paper, and a 40mm owner who finds the battery unacceptable has the option Destiny Ihejirika raised: return it and try the bigger one.