I’ve spent the past week using the ultra-slim Samsung Galaxy S25 Edge as my main phone – and I’ve come to adore it. In fact, I’d wholeheartedly recommend it to most people… If it wasn’t for one humongous issue. 

Now, if you’re a regular reader of my weekly Fast Charge column, you may already know what I’m getting at. I mentioned that I was worried about it in my first impressions piece from last week. 

Yep, you got it; battery life. I suspected that it might be an issue based on my first 24 hours with the phone, but I gave it a chance – battery life always takes a hit on a newly set-up phone while background optimisations are taking place. 

However, after using the phone for the past week, I can see now that it had nothing to do with the background optimisation; the S25 Edge’s battery life is just terrible, plain and simple. 

Small battery + big phone = problem

As I alluded to last week, the main issue is that the Galaxy S25 Edge sports a small 3,900mAh battery – smaller than what’s in the 6.2-inch Galaxy S25 – while simultaneously powering a large 6.7-inch display. Not just any 6.7-inch display either; one with a QHD+ resolution, with plenty more pixels to power than a regular FHD+ panel.

Throw in a top-end Snapdragon 8 Elite chipset with massive performance demands, and you’ve got the potential for issues – as I’ve found out over the past week.

Now, not every phone has long battery life, but even the worst phones from the past few years could outpace the S25 Edge.

I already mentioned how the phone didn’t manage to last 24 hours during my first day using it, but what I didn’t realise at the time was that the resolution was set to FHD+ and not QHD+. Cheeky, Samsung, very cheeky. What’s the point in including a high-res screen if it’s not enabled?

After enabling the top-end resolution, I can see why. Battery life, somehow, got even worse than during my first 24 hours.

Take Monday as an example; I took the phone off charge at 7:45am, went into the office where I used it to listen to music, reply to a few WhatsApp messages and check Instagram, equating to around 2.5 hours of screen-on time overall. By 6pm, it was down to just 3% charge.

Even on quieter days where I’m connected to Wi-Fi all the time, I still couldn’t get the phone to last from morning to night without scrambling for a charger mid-way through the day. In fact, even when charging the phone in the early afternoon, I still find I’ll make it to bedtime with less than 10% remaining.

And, don’t even think about gaming on this phone. I played Archero 2, a relatively simple game with basic 2D graphics, for 30 minutes and saw a whopping 16% battery drain. For context, most phones cap out somewhere between 4-6%, so this is a huge difference in performance. 

The worst part? It could’ve been avoidable

Of course, with the Galaxy S25 Edge’s ultra-slim and lightweight design, there was no way that Samsung could fit the same 5000mAh LiPo cell as the S25 Ultra in its chassis. 

You might assume that Samsung’s hands were tied then, but I’d argue otherwise.

The answer is clear; use silicon-carbon battery technology. The upgraded battery technology essentially allows for higher density batteries in smaller forms –  a combination that’s arguably more useful here than in phones like the Honor Magic 7 Pro where it is present. 

Instead, it comes down to Samsung’s apparent reluctance to switch to the newer battery technology. Since the exploding Note 7 debacle, Samsung has played it very safe where charging and battery tech are concerned. I get it; it was a massive problem at the time, and it cost Samsung millions to fix. 

However, we’ve come a long way in the battery space in the past few years, and I think it’s high time for Samsung to finally adopt silicon-carbon battery tech – for the sake of future versions of the S25 Edge, if nothing else. 

If not that, then at least equip what I’m assuming will be the Galaxy S26 Edge with genuinely fast charging to reduce the amount of time it takes to give the phone a bit of juice – because the 25W limit of the S25 Edge means you’re still waiting over an hour for a full charge. 

It’s a real shame, too

It saddens me to be so negative about the Galaxy S25 Edge because, overall, I’ve come to really appreciate what Samsung has done here. 

The ultra-slim design really is something to behold, and makes more of a difference to everyday use than I ever expected. It has got to the point now where phones like the Galaxy S25 Ultra now feel too thick and heavy, phones that I had no issue using before trying out the Galaxy S25 Edge.

Samsung does have a winning form factor in the S25 Edge – it just really needs better battery tech.