The popular AlzaPower Garnet power bank has significantly dropped in price! It has 20,000 mAh and an LCD display

A power bank with a capacity of 20,000 mAh for less than 600 crowns? That’s exactly the offer Alza.cz has right now. The AlzaPower Garnet 20000mAh currently costs 559 CZK with discount code ALZADNY30, which is a discount of 240 CZK (30%) compared to the original price of 799 CZK. It is one of the best-selling models on the Czech market – over 10,000 units sold and 93% of customers recommend it.

20,000 mAh – how many times can you charge your phone?

A capacity of 20,000 mAh (74 Wh) sounds impressive, but in practice, you won’t get the full capacity from the power bank. The reason? Losses during voltage conversion from 3.7 V (battery) to 5 V (USB port). According to customer reviews, the real usable capacity is around 14,500 mAh, which corresponds to approximately 70–75% of the declared value.

One customer in a review states that it can charge their iPhone 12 about 5 times (the battery has 2815 mAh). If you have a newer phone with a larger battery, like the iPhone 16 Pro Max (4685 mAh) or Samsung Galaxy S25 Ultra (5000 mAh), expect approximately 3 full charges.

LCD display instead of guessing with LED indicators

The main advantage of AlzaPower Garnet over cheaper power banks is the LCD display, which shows the charge status in percentages. You don’t have to guess the remaining capacity based on four LED indicators – you see exactly whether you have 47% or 52%. The display also indicates when Power Delivery charging is active.

The power bank supports all relevant fast charging protocols: Power Delivery 3.0 (max. 20 W), Qualcomm Quick Charge 3.0 (max. 22.5 W), Samsung Adaptive Fast Charge, and older Apple 2.4A. In practice, this means that an iPhone will charge from 0 to 50% in about 30 minutes, and an Android phone with Quick Charge support will charge similarly fast.

Three ports – phone, watch, and headphones at once

AlzaPower Garnet has 2× USB-C (input/output) and 1× USB-A (output only). This means you can charge up to 3 devices simultaneously. Smart IC technology automatically detects connected devices and optimally distributes power.

However, be aware – if you charge all 3 devices at once, the total output will drop to 15 W (5 V / 3 A). This means slower charging. If you charge only one device, you will get the full 20 W (USB-C) or 22.5 W (USB-A). The USB-C ports are bidirectional, so they serve to charge both the power bank and other devices. A USB-C to USB-C cable is included in the package, so you don’t need to buy anything extra.

Safety and Protection

The power bank has 6-fold safety protection against overvoltage, overload, short circuit, overheating, overcharging, and undervoltage. The body is made of flame-retardant material according to UL94 standard, so there is no risk of fire in case of overheating. The battery is of the lithium-polymer type, which is lighter, more resistant to memory effect, and lasts for more charging cycles than classic lithium-ion batteries.

What do customers say?

AlzaPower Garnet has 710 ratings on Alza.cz with an average of 4.7/5 stars. This is an excellent result. 93% of customers recommend it, and the return rate is only 1.63%, which is significantly below average.

Customers most often praise the large capacity, accurate LCD display, and fast charging. One of them wrote: “This power bank pleasantly surprised me. The remaining charge indicator seems more accurate to me than on other models. A good companion for travel and on a plane.” Another adds: “It can charge my iPhone 12 approximately 5 times on a single charge, which is more than enough even for week-long trips abroad.”

The most common complaints concern its weight (415 g is heavier than smaller power banks), long charging time (about 6–7 hours for full capacity), and occasional heating during fast charging. Some customers also mention that the power bank does not automatically turn off after charging the phone – you have to turn it off manually.

Who is AlzaPower Garnet ideal for?

This power bank makes sense for anyone traveling to a festival, on holiday, or a multi-day trip who needs to charge their phone 3–5 times without access to electricity. The LCD display with a percentage indicator is practical because you see the exact charge status. You’ll appreciate fast charging with Power Delivery 3.0 or Quick Charge 3.0 when you want to charge your phone quickly before leaving.

For 559 CZK, it’s a good price-to-performance ratio. If you’re looking for an affordable power bank with good capacity and an accurate display, now is the right time. The promotion with code ALZADNY30 is valid on Alza.cz.

What do you think of this power bank?