The Endless Search for the Perfect Power Bank

This is part of The Endless Search, a series about gear I can’t stop trying to perfect. Previously: The Endless Search for a Better Ergonomic Keyboard and The Endless Search for the Perfect EDC Bit Driver.

Some links in this post are affiliate links — as an Amazon Associate I earn from qualifying purchases, at no extra cost to you. INIU sent me the Cougar P63 to test; they didn’t see this post before it went up.

I bought my first power bank in 2011. Since then I’ve ordered one from Amazon more than a dozen times. I went and looked it up, because I honestly didn’t believe the number either.

I’m always trying to carry as light a setup as possible, so I wasn’t quick to pick up power banks in the first place. My day-to-day life in Brooklyn doesn’t demand one — I’m usually at home or at the office, and seldom in between. Which is part of why it took me so long to figure out the thing this whole post comes down to: I don’t want a power bank for every device. I want as few as I can get away with, each one covering a range of days. Right now, that’s two I carry, plus a big one that mostly stays home.

If you just want my picks: an Anker MagSafe battery for traveling light (with reservations), and the INIU Cougar P63 for days that need more. Skip to where I’ve landed.

How I actually use them

First, some context: I'm often on the move, but I don't use much power while I am. I'm not editing video on a MacBook Pro at full power for hours with no plug, and these days I'm not running big photo or video shoots on location. So I rarely need maximum capacity or maximum output. What I need is the right amount of power for a handful of ordinary situations:

A light day out. All I want is an ultra-portable top-up for my phone in case it runs out. The smallest, lightest thing that fits in a pocket wins. For this I've been using Anker's MagSafe batteries. They're OK. The size doesn't quite match the phone and they don't feel great in the hand. They get hot charging over MagSafe, and they're very slow.

A short trip to a coffee shop. I need enough to top up my laptop if I can't get a seat near a plug. The INIU handles this, plugged straight into the MacBook with its GoCord.

A long day out with my kids in Brooklyn. Multiple phone top-ups, hours from home. This is where the INIU shines: enough capacity for several full charges, small enough that I don't notice it in the bag.

A long laptop session. I do this rarely. It could be a long stretch at a coffee shop with no plug, but more likely it's a plane where the seat plug isn't working. I used to bring the big PowerCore for this, but the INIU does the job just as well: nearly the same capacity (25,000mAh against 25,600mAh) and more output (100W against 87W), in a much smaller bank.

Before the INIU, this was the PowerCore's job: my mobile office setup: MacBook, portable monitor and folding keyboard.

Powering my YouTube setup. The bank runs my Panasonic GH5 through a USB-powered dummy battery, along with the Accsoon wireless video transmitter, so I'm not swapping camera batteries mid-shoot. I also love SmallRig's USB-C camera battery, which charges straight off any of these banks.

The PowerCore powering the camera rig, and held in an ARNARKOK clamp.

On the way to kitesurfing. I always forget to charge my GoPros at home, so they charge off a power bank in the car on the drive to the beach.

The INIU could cover every one of these except the first. On a light day I don't want to carry a bank that size, I want something that disappears onto the back of my phone. That's why I've ended up with two.

What I’m actually looking for

Like the bit drivers, I didn’t know what I cared about until I’d bought the wrong thing enough times:

• The small one is shaped like a phone. The bank I carry most is mostly charging my phone, so it should stack with it in one hand or slide into the same pocket.
• Thin over chunky. Flat things pack. A bank that's thick in every direction is awkward in a bag however you turn it.
• A cable comes along, but isn’t built in. I like having the cable right there, as part of the bank. I don’t want one tucked inside the body, even a replaceable one: it makes the bank bigger, and a cable I can’t replace means the whole bank is done when it breaks.
• USB-C only. I don’t use USB-A ports anymore. Every one on a bank is space and weight I’m carrying for nothing.
• Obvious which port does what. Both the INIU and the Anker Prime start charging a phone the moment it's plugged in, with no button to press, so that part is solved. Ports are another story. On the INIU, I plugged my laptop into the lower-power port (45W, against 100W on the main one) and it didn’t charge as fast. That’s not really an INIU problem. I could make the same mistake on any of these banks, because they all have ports with different power levels that look identical.
• Fast and cool. A bank that heats up and trickles charge isn’t saving me anything.

The PowerCore (left) still carries two USB-A ports I never use. The INIU has one too.

Shape ended up mattering most, and it’s the thing nobody has quite gotten right.

Every power bank I’ve bought

Most of these I bought too long ago to say much about, so this is the receipt trail, plus whatever I still remember.

• April 2011: Satechi iCel, 5,200mAh. My first, for an iPhone 4. For years after this, a power bank meant one thing to me: an emergency phone top-up while I was out.
• April 2015: Anker Astro E4, 13,000mAh. Two days after it arrived I ordered the smaller one below.
• April 2015: Anker Astro 2nd Gen, 6,400mAh. The smaller one. This one stayed.
• May 2015 and July 2016: AmazonBasics, 5,600mAh. I bought it twice, which probably says it was good enough.
• October 2016 and September 2017: Jackery Bolt, 6,000mAh. Bought twice too. It had a Lightning cable built in, which was nice. But the cable never sat at the right angle, so holding the phone and the bank together while it charged was awkward. And when the cable wore out, there was no replacing it.
• May 2019: ZMI USB PD Backup Battery & Hub. My first bank that could charge a laptop. I bought it partly for the USB hub and never used the hub once. I'm pretty sure I eventually lost it, or it stopped working.

Then, for four years, nothing.

• November 2023: Anker PowerCore III Elite 25,600mAh 87W (also sold as the Anker 737). With the ZMI gone, I needed a laptop bank for a work trip. It's my long-haul flight bank: big enough to run the laptop or keep an iPad going through movies. It's also so bulky that I rarely took it out of my bag at my seat, especially since a lot of those flights have plugs anyway.
• March 2024: Anker MagSafe Magnetic Battery, 5,000mAh. The appeal is obvious: it snaps onto the back of the phone, no cable at all. In practice it gets hot charging over MagSafe and it's slow. It's still what I carry on light days, because nothing smaller has replaced it.
• June 2024: Anker 26,800mAh. Three days after ordering it, I bought a second 25,600mAh 87W.
• February 2026: Anker Prime 20,100mAh. 220W max across three ports, with an app. It lives at my office, because some of the call booths don't have working wall plugs. The shape is awkward, it's heavy, and I rarely need fast charging, so it's the one I like least.
• 2026: INIU Cougar P63, 25,000mAh, up to 100W. INIU sent this one to me to test. More on it below.

The INIU Cougar P63

What I like:

• The size. It's noticeably smaller and lighter than the other big banks, and that's the best thing about it.
• The versatility. It's small enough to carry on a day out, and it can still charge a laptop.
• The cable is right there. I love having a cable attached to the bank, so I'm not digging through a bag for one. The lanyard is a good idea too, even if it doesn't quite work (more below).
• The fit and finish are nice.
• The screen is a nice touch, though not something I need.

What could be better:

• The screen is hard to read in the sun, so in practice it isn’t very useful.
• It scratches easily. The finish looks good until it's been in a bag for a while.
• The lanyard is the cable. It’s a great idea, since you always have a cable with you. But the loop is too small to get over my wrist, which is exactly when I’d want it: carrying a laptop and a power bank in one hand, it’s easy to drop one of them. And it comes loose if you try to pull it apart to put on your wrist.
• You can’t buy another GoCord. INIU doesn’t sell it separately, as far as I can find, either as a replacement or in a longer length. A regular USB-C cable works, but then it’s not a lanyard anymore. Selling both would fix most of my cable complaints.

→ INIU Cougar P63 on Amazon

How the big ones compare in size

From the left: the Anker PowerCore III Elite, the Anker Prime and the INIU.

Side on: the INIU, the PowerCore, and the white MagSafe battery underneath.

The same three on their sides. The PowerCore is the thinnest. The Prime is about as thick as it is wide.

I like thin things. They pack more easily for travel: a flat bank slides into a laptop sleeve or a bag's side pocket, while a chunky one takes up its own corner. That's my problem with the Anker Prime. Its cross-section is almost square (44 × 50 mm), so it's just as thick whichever way you turn it, and it's awkward in a bag no matter how you pack it. It is the fastest of the three by a wide margin (220W across its ports), but I don't need that often enough to carry its shape around.

The INIU is the impressive one. Compared to the old PowerCore III Elite, it gives up 2% of the capacity (25,000mAh against 25,600mAh) for a bank that's 24% smaller by volume, 35% lighter, and takes up half the footprint. Compared to the Anker Prime, it holds 24% more while being 14% smaller.

The old PowerCore shows that flat on its own isn't the answer. It's the thinnest of the three at 24 mm, but it's a slab: two-thirds longer than the INIU and wider too. It's nearly 4 cm longer and more than 1 cm wider than my iPhone 15 Pro, so I could never hold it behind the phone in one hand.

How I'd make the INIU better

Most of the time a power bank sits in a bag while my phone charges. But every so often I need the power and the phone at the same time: a call that runs long on a nearly dead battery, or directions on a day out with the kids. Then I'm holding the bank and the phone together in one hand, and that's where the INIU's shape stops working.

The INIU is already almost exactly as wide as my iPhone 15 Pro (70 mm against 70.6 mm). The problem is the other two dimensions. It's 37 mm shorter than the phone, so it sits as a lump on the lower part of the back instead of lining up with the edges. And at 36 mm it's more than four phones thick, so phone plus bank is a 44 mm stack. That's too thick to wrap a hand around comfortably.

So I'd change two things and leave the width alone:

• Make it as long as the phone: 110 mm to 146.6 mm, about a third longer. The bank would cover the whole back of the phone, so the two line up edge to edge and hold like one object.
• Make it thinner: 36 mm to about 27 mm, a quarter thinner. Spreading the same volume over a longer outline makes room for that without losing capacity. It would still hold roughly the same 25,000mAh.

The stack in your hand would drop from 44 mm to about 35 mm, and because the bank matches the phone's outline there's no ledge where the bank ends. It would weigh the same in your pocket and hold the same charge. It would just feel like holding a thick phone instead of a phone with a brick strapped to it. And 27 mm isn't a stretch: the old PowerCore is already 24 mm thick.

And a longer GoCord

The other fix is to stop holding the bank at all. The INIU's cable, which INIU calls the GoCord, doubles as its carrying loop. It's detachable and short: about 0.3 m, or a foot. That's fine for tossing the pair in a bag, but too short to let the bank sit on your lap while you use the phone. INIU should sell a longer GoCord for exactly this.

Where I’ve landed

I don’t want a different power bank for every device I own. I want as few as possible, each covering a range of situations. Right now that’s two:

• Extreme portability: small. An Anker MagSafe battery. Mostly for charging my phone. It snaps onto the phone, so it lives with the phone. It's the weakest link in the kit: slow, warm, and not quite the right shape.
• Everything else: medium. The INIU P63. It’s for days when I need more than one phone charge, or some charge for my laptop. It charges my phone several times over on a long day out in the city with my kids, and it can top up my laptop in the rare coffee-shop session with no plug.

I still have the 25,600mAh 87W PowerCore, but the INIU now does everything it did in a much smaller bank, so it stays home.

The INIU isn't perfect, but its smaller size and weight make a real difference. I carry it at least once or twice a week. I never carried anything as big as the PowerCore more than once or twice a month.

Still, neither of my two is "the one" yet. The small one should be faster and run cooler. The INIU should be shaped like my phone, with a loop big enough for my wrist and a GoCord I can replace. Until someone makes those, the search continues.

What I haven’t tried yet

Newer magnetic batteries. My Anker MagSafe battery is a couple of generations old. The newer ones use the Qi2 standard and are thinner and faster, like the Baseus PicoGo AM52 or INIU's slim 10,000mAh. The catch is my phone: the iPhone 15 Pro tops out at 15W on Qi2, and the fastest 25W speeds need an iPhone 16 or later. Even 15W would be twice what my old Anker manages.

Different shapes. The Baseus Blade 100W is 18 mm thin and about the size of a small tablet, so it slides into a laptop sleeve next to the laptop. If you run a laptop off a battery a lot, that's a smarter shape than any brick. I mostly charge a phone, so it isn't for me.

Much bigger banks. If I ever became a heavy power user on the go, like when I was running photo shoots with LED lights, a portable monitor, a laptop and a fan (the loft we shot in got hot), I could see carrying something two or three times the INIU's size. But anything over 100Wh can't fly without airline approval, and most of the options are shaped like lunch boxes, which doesn't seem practical. The one exception I found is the Krisdonia 50,000mAh: a flat slab about as thick as the INIU, with twice the energy. It's an old design, though, charging laptops through a barrel plug instead of USB-C.

Videos worth watching

• I Own 60 Power Banks. Only 3 Are Worth Buying (2026), MobileReviewsEh. Useful for seeing how the INIU stacks up against the rest of the field. He buys every bank himself and measures it on a test rig instead of trusting the box, and his #2 pick is the INIU P62-E1, a 20,000mAh sibling of my P63.
• Power Bank Capacity Explained - Why the Numbers Lie, Jackington. Why a 26,000mAh bank gives you about 3.5 phone charges, not 5. Wired charging loses roughly 30% of the energy as heat, and wireless loses closer to 40%. That also explains why my MagSafe battery runs warm and doesn't go very far.

More from The Endless Search: The Endless Search for a Better Ergonomic Keyboard · The Endless Search for the Perfect EDC Bit Driver.