Xiaomi USB Battery Charger and ZI5 / ZI7 (Review)

Written by Adrin S

When it comes to batteries and chargers, Xiaomi has a basic range featuring the most common battery types and sizes — rechargeable Ni-Mh in AA (ZI5) and AAA (ZI7) sizes and alkaline batteries sold as the Rainbow ZI5 / ZI7 (AA and AAA sizes). The company also has a compact USB battery charger for both AA and AAA batteries.


In this review, we will be taking a look at the Xiaomi charger, the ZI5 AA and ZI7 AAA rechargeable batteries and also the Rainbow ZI5 alkaline battery.

Xiaomi USB Battery Charger

Smaller than a pack of cigarettes, the Xiaomi charger has got to be the most compact battery charger I’ve ever seen. It also weighs a featherly 66g (with USB cable). Staying true to Xiaomi’s minimalist design language, the charger features an all-white plastic design with a frosted battery bay cover that slides off. The plastic casing feels, well, plasticky and the unit heats up quite a bit when charging batteries. Since the unit is so small and made mostly of plastic, the heat doesn’t have much material to transfer to which explains why it tends to heat up easily.


Damage from heat isn’t an issue, however, since the charger has built-in overheat protection that shuts off power when things get too hot. Other safety features include protection from over-charging, over-discharge, short circuits and reverse polarity.


The Xiaomi USB charger is a quick charger which means it can charge 4 pieces of AA batteries in 4 hours (2 hours if only 2 batteries are charged). It also doubles as a back-up power bank — one key feature that sets it apart from other battery chargers. Although this feature seems neat, the Xiaomi USB charger is no substitute for a proper power bank.

It can be used to charge or power small devices such as the Xiaomi Portable USB LED light but when it comes to charging smartphones or small tablets, it is only good as an emergency charger for topping up. Charging a 3000mAh smartphone battery from 10% to full isn’t possible with this charger simply because it wasn’t designed to be a proper power bank. When attempting to perform a full charge on my smartphone, the unit heat up quite a bit and managed to put in only 15% of charge before shutting itself off, possibly due to overheating or for some other reasons.


However, although the Xiaomi USB charger won’t make the cut as a proper power bank, it still offers plenty of value costing only $7 or so if you purchase it from online stores such as GearBest. It also works very well when charging Ni-Mh AA and AAA batteries as I’ve not had any issues with that so far.

Xiaomi ZI5 and ZI7 (Rechargeable)

The Xiaomi ZI5 AA and ZI7 AAA rechargeable batteries are available in dual-tone sets (black and white) which makes it easy for you to differentiate between sets of batteries so you can easily sort out which ones have been used and which ones have been freshly charged. They’re also shipped with free high quality plastic casings. The ZI5 has a capacity of 1800 to 1900mAh while the smaller ZI7 has a capacity of 700 to 750mAh — these are pretty standard for AA and AAA rechargeable batteries.


Based on Xiaomi’s marketing literature for these batteries which emphasize on their 1500-cycle lifespan, low self-discharge rate and the fact that the batteries are manufactured by a “famous manufacturer in Japan”, my guess is Xiaomi’s batteries are made by Sanyo or the same manufacturer that makes Sanyo’s popular Eneloop rechargeable batteries. This isn’t surprising since Xiaomi is known to outsource the production of many of its products to third party manufacturers and then market them under the Xiaomi brand.


I have been using these batteries for a few weeks now and so far they haven’t been disappointing. Whether they stand up to the test of time remains to be seen. The ZI5 are available for $7.59 (with shipping) per pack at GearBest, half the price of a pack of 4 AA Eneloops. This is quite an impressive price since the quality on the ZI5 and the smaller ZI7 seem very similar to original Eneloops (I’ve used plenty of Eneloops over the years).

Xiaomi Rainbow ZI5 and ZI7 (Alkaline)

Xiaomi’s ZI5 and ZI7 alkaline batteries come in packs of 10 multi-colored batteries and are shipped with their own 10-battery case. Priced at about $5 (AAA) and $6 (AA) at most online stores, they are ridiculously affordable. These batteries are mercury and cadmium-free which means they’re non-toxic and environmentally friendly.


Built quality on the ZI5 alkalines seem very similar to the rechargeable ZI5’s. Xiaomi claims its alkaline batteries have very low self-discharge rates and are good for up to 7 years of storage thanks to various features in the batteries that prevent leakage. This is great if you intend to store these batteries for years since alkaline batteries have the tendency to leak over time when they aren’t used regularly.

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Adrin S

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