Alza sells a new 50,000mAh power bank for only 899 CZK! It has a display, a strap, and can charge three devices at once

In the pursuit of higher numbers on the packaging, we’ve reached a point where fifty-thousand-mAh power banks are selling for a few hundred. The new ChoeTech PD22.5w Power Bank 50000mAh has arrived at Alza for 899 CZK and appears to be an ideal companion for long trips where you might be without an outlet for several days. In addition to an excellent price-to-capacity ratio, it boasts a display, a strap, and three outputs.

What does the ChoeTech power bank offer?

The main draw is, of course, the 50,000 mAh capacity, which makes the power bank more of a home or travel energy reservoir than a pocket accessory. You have three outputs available – specifically, a pair of USB-A and one USB-C – allowing you to charge up to three devices simultaneously. This is useful when you need to charge your phone, headphones, and tablet all at once without swapping cables.

Here, however, we encounter the first compromise. The total output is only 22.5 W, with the USB-A port handling a maximum of 22.5 W and USB-C stopping at 20 W. This is sufficient for a quick phone charge during a short break, but it’s too little for charging a laptop or for full fast charging of modern flagship phones (which commonly draw 45 to 100 W today). The power bank supports the USB Power Delivery standard, intelligent power distribution between ports, and a set of protections against overvoltage, overload, short circuit, and overheating.

Among its features, worth mentioning are the LED display with an accurate percentage of remaining power, USB-C input, and an integrated carrying strap. You’ll appreciate this, as at a weight of 1090 grams, it’s a device you won’t carry in your pocket.

How many times can you actually charge a phone from it?

Don’t be fooled. A simple division of 50,000 / 5,000 = 10 (if you have a 5,000mAh smartphone) might promise ten full charges, but due to energy losses, you’ll never reach that number.

The 50,000 mAh capacity is stated at the voltage of the internal cells, which is typically 3.7 V. When converted to watt-hours, this amounts to 50,000 mAh × 3.7 V = 185 Wh of energy. However, the USB output transforms this voltage upwards (to 5, 9, or even 12 V), and the phone then converts it back down internally for its battery. During each such conversion, some energy is transformed into heat, so the real efficiency of quality power banks ranges around 70 to 80 %.

If we calculate with 72% efficiency, approximately 133 Wh will remain usable from the original 185 Wh. As stated by Counterpoint Research, the average current phone has a battery of around 5,300 mAh, which corresponds to about 20.4 Wh. Dividing these figures gives us a result of approximately 6.5 full charges – not ten, as simple math might suggest.

How many times you can charge based on phone type

The mobile market is very diverse today. While Apple and Samsung stick to more compact batteries, Chinese manufacturers equip phones with massive silicon-carbon cells. The actual number of charges thus varies depending on what you have in your pocket:

A practical note at the end: if you actively use your phone while charging from the power bank (gaming, navigation, browsing), the number of charges will decrease even further. This is because the phone will immediately consume some of the supplied energy, and increased heat will further degrade charging efficiency.

The catch you’ll encounter at the airport

Large capacity also has a downside that sellers are reluctant to mention. Rules for transporting lithium batteries on an airplane are based on watt-hours: up to 100 Wh (i.e., approximately 27,000 mAh) you can take a power bank in your carry-on baggage without restrictions, between 100 and 160 Wh only with airline approval, and anything over 160 Wh is prohibited in personal air travel – both in carry-on and checked baggage.

With its 185 Wh, ChoeTech exceeds this limit, so you simply cannot take it on a plane. And it’s good to know that rules are likely to tighten in 2026 – after a fire caused by a power bank on board in South Korea, several carriers (Lufthansa Group, Japan Airlines, Emirates, Qantas, and others) have also banned the general use of power banks during flights. For this particular power bank, it means only one thing: it’s a backup for your car, a cabin, or home, not a companion for flights.

Who it’s suitable for and who it’s not

The ChoeTech PD22.5w makes sense for anyone who needs a large power reserve away from an outlet – for a festival, camping, a weekend cabin, in the car for longer trips, or as a home backup power source during an outage. You’ll also appreciate it if you commonly charge multiple devices at once. For its capacity-to-price ratio at 899 CZK, it’s hard to beat.

On the other hand, I do not recommend it if you fly frequently (see above), want to fast-charge a modern flagship phone at its full power, or charge a laptop – for that, 22.5 W, or 20 W via USB-C, is not enough. Also, be aware that charging the power bank itself with such a large capacity will take around eight or more hours, and its weight of over a kilogram makes it a device you carry in a backpack, not in your pocket. For those who want a more versatile solution, even for work, smaller 20,000mAh models with 100W output (Anker, UGREEN) can be found for a slightly higher price, which, while offering fewer charges, do so without compromises in performance and can even be taken on a plane.

So, if you’re purely looking for as much energy for as little money as possible and know that you’ll keep the power bank at home, in the car, or on road trips, 899 CZK is a reasonable investment. Just expect around six to seven phone charges, not ten.

Would you take such a large power bank, or would a smaller and lighter model suffice for you?