It doesn't even cost 500 CZK! This 20,000mAh is on sale again, has a display, and charges three devices simultaneously

Do you want a 20,000 mAh power bank with multiple ports and a display, but don’t want to spend more than five hundred? The ChoeTech B729 is now available on Alza for 454 CZK instead of 699 CZK with code ALZADNY35, returning to its January price. With over 2,000 units sold and a rating of 4.7/5, it’s a proven and popular model among Czech users.

Quick summary:
✅ Makes sense if you’re looking for a powerful travel power bank that can charge a mobile phone four times and fits into carry-on luggage.
⚠️ Consider if you need a pocket-sized power bank for daily use – 420 g is more than compact 10,000 mAh models.
💡 For 454 CZK, it offers one of the best price-to-capacity ratios currently available in the 20,000 mAh segment.

Why this power bank is interesting

ChoeTech B729 falls into the category of travel power banks – models you buy for multi-day trips, holidays, festivals, or a cabin without electricity. In practice, a 20,000 mAh capacity is enough to charge an average phone approximately 3 to 4 times.

The second reason is exceptionally strong user feedback. A rating of 4.7 out of 5 from 332 customers, with 274 of them giving a full 5 stars, over 2,000 units sold, and a warranty claim rate of only 0.99% – these are numbers that not all models in the cheap power bank segment achieve. ChoeTech as a brand has a long tradition in charging products, so it’s not an anonymous Chinese no-name.

Key parameters: 20,000 mAh, PD 22.5 W, and three ports

The power bank has three outputs – 2× USB-A and 1× USB-C, with USB-C functioning as both input and output. When charging three devices simultaneously, you’ll achieve a total output of 15 W; individually, 20 W via USB-C and up to 22.5 W (Power Delivery) via USB-A. One of the Slovak users tested it in detail and confirmed that the power bank indeed maintains the declared performance – 22.5 W via USB-A and 25 W via USB-C when using a 25W adapter.

Important practical detail: for full charging of the power bank itself, you need a charger of at least 25 W. If you use a 15W charger, the power bank itself will only charge at 5W speed, which means a significantly longer time for a 20,000mAh capacity. The included USB-C cable can handle full-speed charging, but according to some users, it has a reserve in this discipline – if you have your own high-quality USB-C cable with PD support, use it.

The LED digital display shows the charge status in percentages and indicates fast charging with a colored icon. This is a significant improvement over models with just four dots – you know exactly how much power you have left and don’t have to guess if the power bank will last you another full day.

Practical aspects: display, weight, airplane

A weight of 420 g is to be expected for a 20,000mAh capacity – compact 10,000mAh power banks weigh roughly half, but also have half the energy. For daily carrying in jeans pockets, it’s a higher burden, but for a backpack or carry-on luggage, the weight is negligible. The body is plastic, well-processed to the touch, and one user described the quality as “very good.”

An important note for people traveling by plane: 20,000 mAh at 3.7 V corresponds to 74 Wh, so it fits within the 100Wh limit for carry-on luggage, which applies to most airlines. You can therefore take the power bank with you into the cabin – just remember that power banks generally must not be placed in checked luggage under the seat; they must be with you. For shorter trips with moderate weight, it is one of the more versatile travel models.

Practical tip for the display: from a large number of reviews (including for sibling models 30,000 and 50,000 mAh), the same misunderstanding repeatedly arises – the display is protected by a thin protective film from the factory, which needs to be peeled off after unpacking. The unpeeled film carries minor scratches from handling, making it look as if you received a damaged item. If you see scratches after unpacking, look closely – it’s probably the protective film.

What users say

Out of 332 ratings, 274 customers gave a full 5 stars, and another 26 gave 4 stars – meaning 90% of customers recommend the product. Four things dominate the praise: price/performance ratio, real capacity matching declared specifications, a display with percentage charge status, and the ability to charge 3 devices simultaneously. One user, after half a year of use, writes that the power bank “holds its capacity excellently” and another calls it a perfect companion for a bus trip to England and back.

Three recurring points emerge from the criticism. The first is that the included USB-C cable may charge slower than the power bank theoretically could – the solution is your own high-quality PD cable. The second point is the higher weight of 420 g, but reviewers usually consider this a logical trade-off for the 20,000mAh capacity. The third, rarer point is a quiet whistling sound in some units during charging – not all users heard it, but one reviewer of Slovak origin points it out. However, the warranty claim rate of 0.99% is very low, so it’s not a systemic issue.

If this particular model didn’t appeal to you, but you’re looking for a power bank on sale, you can also check out current Alza Days, where other discounted power banks of various capacities and chargers continuously appear. Stock levels for best-selling models usually deplete quickly.

When it doesn’t make sense

If you’re looking for a compact pocket power bank – for a shoulder bag or a smaller handbag – the 420 g weight and dimensions of a 20,000mAh model will hinder you more than help. For daily carrying, a 10,000mAh variant of the same model (B728) for 449 CZK, weighing roughly 225 g, makes more sense. Similarly, if you want wireless charging or MagSafe, this power bank won’t provide it – in that case, look for the Swissten or Epico Mag+ series.

The second case is when you want very fast charging above 22.5 W (e.g., 65 W for a laptop). This power bank won’t provide enough power to charge a MacBook or most modern laptops – for those, PD 65 W and higher is needed (e.g., AlzaPower Parade Gen2 100 W). And if you primarily charge an iPhone with native 20W fast charging on the go, a lighter 10,000mAh variant will suffice.

Verdict: who it’s worth it for

The ChoeTech B729 for 454 CZK makes sense for anyone looking for a universal 20,000 mAh travel power bank with fast charging and a status display. The combination of three ports, PD 22.5 W, airplane-friendly format, and a very low warranty claim rate of 0.99% makes it a safe choice at this price point, confirmed by 2,000+ units sold and 90% satisfied customers. The price of 454 CZK is a return to its January low, so if you’re considering a purchase, now is an opportune moment. Conversely, if you need a compact 10,000 mAh for your pocket or a high-power 65W+ for a laptop, look for other models.

Do you choose a power bank more by capacity, or do you prefer to look for low weight and compact dimensions?