Well, let's talk about the Mi 10400 in detail. As the name suggests, it is a power bank. In other words, it is a battery -- similar to the one in your phone or tablet - encased in a metal body that has two ports. One of these ports -- a micro USB port similar to the one in your phone -- is used to charge the battery. The other port -- a full-size USB port -- allows you to connect a cable to it and then use it to charge your phone or tablet.
It works just like other power banks. But the big difference, literally, is the size of the battery. Unlike the other power banks which have a battery with capacity of 2000, 3000, or 5000 mAh, the Xiaomi power bank has a battery that can store 10,400 mAh.
The large battery size means that the Mi 10400 is also slightly bigger and heavier than most of the power banks available in the market. But the design of the device means it looks slick and well made. The device uses anodized aluminium shell, which gives it a very Applesque appearance. It looks like Jony Ive designed it and not some Xiaomi engineers. The aluminium shell also makes the device feel reassuringly hefty, which is a big difference compared to how the plastic power banks feel.
Overall, the build quality of the product is impeccable and finishing is premium. The round power button snuggly fits in its socket. The 4 LED lights that show the status of the battery are small and go well with the minimalist design.
As far as using the device is concerned, we are very happy with its performance. Due to the large capacity, it takes almost 15 to 16 hours before it gets fully charged but once it is full you can safely use it for a few days. The charging speed also depends on the charger. We tested it with a charger that can supply 1.2A (amps). If you use it with a charger that can supply 2A or more, it will charge faster.
Similarly, how fast the Mi 10400 can charge a phone or tablet depends on the circuitry inside the device but in our use we found that it completely filled the empty Nexus 5 battery in little less than two hours. This is good performance. Xiaomi says that the Mi 10400 can supply 2.1A power while charging a device, which looks about right based on our experience with it.
As we said earlier, the Mi 10400 is one fantastic product. It packs in a battery that is huge, has premium and polished looks and has performance that is very good. But that is not the primary reason why it is a fantastic product. That reason is its price. The Mi 10400 has a price of Rs 999! Yes, you read it right. This absolutely fantastic power bank has a price of just Rs 1299.
At this price, buying the Mi 10400 is no-brainer. If you travel a lot or often find yourself stuck in situations where your phone's or tablet's battery can't keep pace with you, get the Mi 10400. It is the best Rs 1299 you will ever spend.