CUKTECH 15 Ultra Power Bank review: Power meets portability

After testing a wide variety of battery packs, I often find myself craving something more balanced. Smaller ones are very convenient to carry around, but are never powerful enough. The bigger ones get the job done, but they can be a bit too hard to carry around. The CUKTECH 15 Ultra Power Bank offers a nice proposition, offering something right in the middle. It aims to find a balance between true portability and power. Does it accomplish it?

I’ve been testing the CUKTECH 15 Ultra Power Bank for a couple of weeks and am ready to tell you whether it makes the cut. Let’s jump right in.

Of course, the first thing you notice as you unbox anything is its design and build. This is especially important when dealing with a battery pack, which is an accessory you will see and show off everywhere. You’ll also carry it around, which means it will undergo quite a bit of torture, so you need to make sure it will survive anything you put it through.

I previously reviewed the CUKTECH 20 Power Bank, which looks cool and offers a sturdy construction comparable only to the best. It has survived months of continuous use, rolling around my trunk, and keeping my devices charged wherever I go.

I am happy to report that the CUKTECH 15 Ultra lives up to the same standard as the 20. While smaller at 5.98 x 2.25 x 1.75 in, and made of plastic, it by no means feels cheap. The construction seamlessly blends into a solid little brick with zero moving parts, no wiggling ports, and a singular button with a solid click.

It is a little on the heavier side at 1.3 lbs, but it doesn’t feel uncomfortably heavy. Instead, it feels like the kind of heft that equates to quality. It’s a balanced weight, similar to carrying a gold coin. It just feels satisfyingly heavy. And I mean, the weight makes sense when you consider this thing carries 20,000mAh of battery capacity.

You won’t really feel its weight if it’s just in your backpack. It does fit in my pants pockets, though. And if you plan to carry it around in your pocket or in a small purse, the weight will definitely be more noticeable.

Enough battery for a couple of days

In my experience, the CUKTECH 15 Ultra lasted me a couple of days on the go. I went to San Diego for the weekend (Saturday and Sunday) and came back home with a dying battery pack, but during that time it managed to juice up my smartphones (a Pixel 8a and an iPhone 15), smartwatch, and my wireless earbuds. I would usually charge everything at night, and recharge the phones on Sunday afternoon, during my drive back.

Considering the 20,000mAh battery capacity, this level of usage makes sense. It’s a great little battery for commuters, quick weekend campers, or mobile device backup during power outages.

Of course, your mileage may vary, depending on what you power, because this thing can charge more than smartphones and mobile accessories.

Considering the size and price, the CUKTECH 15 Ultra bank is super powerful. It has a max output of 165W, though none of the ports can reach that mark individually. The CUKTECH 15 Ultra Power Bank has two USB-C ports and a USB-A connection. Based on my tests, the one labeled “IN1/OUT1” can reach 140W, while the “IN2/OUT2” one maxes out at 65W. The USB-A connection is slower at 18W.

Of course, these max speeds are only achievable when charging one device at a time. Speeds get slower as you plug in more gadgets simultaneously.

To put things into perspective, the 140W port is powerful enough to charge most tablets and laptops. I have also used it to charge portable speakers, my mirrorless camera, and a portable coffee maker. Chances are that if something uses a USB port, this battery pack can power it.

This is because it supports Power Delivery 3.1 and PPS standards, which means it can fast-charge most devices. For reference, even some high-end smartphones like the Samsung Galaxy S25 Ultra are limited to 45W, but this is among the fastest-charging mainstream phones around. The fastest-charging device I have right now is the Xiaomi 11T Pro, which can reach a whopping 120W.

OK, so this is likely my favorite feature on the CUKTECH 15 Ultra. Both USB-C ports can work as inputs at the same time. CUKTECH calls this “Beast Mode Self-Charging.” It pretty much makes both ports work together to reach a maximum of 165W of input. So yeah, it can take in just as much wattage as it can output.

I never saw it reach 165W, but I was able to consistently recharge it at over 150W, and when it does, it’s incredibly fast to fill up. It was recharging at about 1% per 20 seconds or so during its fastest moments. Of course, it will eventually slow down to control the battery’s heat, but it is still pretty impressive.

So, if you often find yourself in a rush to catch a quick charge, this is the fastest recharging power bank I have tested. It’s honestly kind of unbelievable. The only caveat is that you will have to carry a couple of cables. And unless you have a really capable multi-port charger, you will also need a couple of fast bricks to reach such speeds.

Overall, I am really enjoying using the CUKTECH 15 Power Bank. It’s enough to keep my mobile devices charged over a weekend (two days), all without reaching for an outlet. Of course, it will die much faster if you start using it with tablets or laptops; in that case, it might not even last one day.

That said, I purposely didn’t charge it during my short trips because I wanted to test how long it lasted. I could have plugged it in from time to time, and it charges really fast, giving you 70% in just 20 minutes when using Beast Mode. With a bit of effort regarding recharging the battery, I could have made it work for longer, or used it with my higher-power devices without much of an issue.

After a couple of weeks, I find myself gravitating more towards the CUKTECH 15 Power Bank, just because it is plenty powerful for my everyday use and is easier to carry. The CUKTECH 20 just lives in my car these days, just in case I need more juice, but I haven’t really needed to use it so far. At $109.99, the CUKTECH 15’s price is pretty fair for a power bank of this caliber, with rivals like the Anker Prime 200W ($129.99 at Amazon) going for $30 extra. Not to mention, discounts are pretty common.

If you need more power, though, and don’t mind carrying something larger and heavier, the CUKTECH 20 Power Bank ($119.99 at Amazon) is a nice upgrade. As for me, the CUKTECH 15 Power Bank will continue to be my daily go-to. It’s just enough power and speed, and the smaller ones usually leave me wanting more. I think this one hits the sweet spot.