iCulture reviews: Nuki Power Pack, a rechargeable battery for your door lock

We are very satisfied with our Nuki Smart Lock (see review), but one thing was not quite perfect: we had to replace the batteries regularly, because they run out quite quickly. The Nuki Power Pack solves that problem: you do not have to buy new batteries all the time, which is better for the environment and for your mood. Charging is done via a USB port.

The Power Pack costs 49 euros and has been sold out for months since its introduction, but it is unclear whether this is due to the enormous demand or due to production problems. We tested it to see if you really need one. We waited a bit longer with this review because the Power Pack was constantly sold out. That is still the case, but if you find one in stock soon, it is important to strike quickly.

Text, review and photos: Gonny van der Zwaag (@gonny). The Nuki Power Pack was provided by the manufacturer for this review. Not all products require an extensive review. For cables, batteries and other small accessories, we have the more concise ‘iCulture looks at’ reviews.

Nuki Power Pack in brief

These are the most important features of the Nuki Power Pack:

• Rechargeable battery for your Nuki Smart Lock
• Offers promised battery life of 12 months (with 8 opening/closing times per day)
• Percentage can be viewed in the Nuki app
• NiMH batteries: 4.8 V DC / 2500 mAh / 12 Wh
• Dimensions 33 x 55 x 70 mm
• Nuki works with HomeKit
• Suggested retail price 49 euros
• Available via Nuki-shop, Coolblue and other stores (but sold out for months)

Design and appearance Nuki Power Pack

The Nuki Power Pack is a rechargeable battery for your door lock. You place it in the battery compartment of the Nuki, a door lock that is very popular among HomeKit users. It is one of the few HomeKit door locks that actually works well – but you do have to replace the batteries regularly. We used regular and rechargeable IKEA batteries for this, but they were empty after 10-15 weeks. Better quality batteries last longer, but are expensive and ultimately just create a mountain of waste. The Nuki Power Pack gives you a bit more peace of mind: you only have to charge it every so often (every 12 months, according to the manufacturer) and then you don’t have to worry about it anymore. Sounds good.

The Power Pack is essentially a black plastic frame in which four rechargeable AA batteries are attached. Together they form a single construction. It might have been nicer if Nuki had finished it a bit tighter, so that you don’t see the loose batteries, but the design isn’t all that important. After all, it’s barely visible when it’s in the lock. The Power Pack protrudes a bit further (partly because of the USB-C ports) than when you use loose batteries, but this isn’t disturbing.

Installation and use of the Power Pack

Installation is a matter of removing the original battery holder and inserting this Power Pack. You have to press firmly so that it ‘clicks’. The battery pack was then immediately recognized in the app. With a slider you can remove the Power Pack again, after which it falls out by gravity.

We have been using the Nuki Power Pack for several months now and have not had any problems. However, we do wonder why Nuki did not immediately opt for this solution with a rechargeable battery. The most important reason we can think of is that the lock itself would have become €49 more expensive. Now you have the option of opting for rechargeable batteries, which cost around €10-15, but therefore have to be replaced more often.

Charging and battery life Nuki Power Pack

Before you place the Nuki Power Pack, it is a good idea to fully charge it. This takes about 10 hours and is done via one of the two USB-C ports. Nuki supplies a USB-C to USB-A cable, but no adapter. This is very normal these days, so we are not difficult about it.
Pay attention to whether the USB-C plug is deep enough. In our case, it initially did not work to charge properly, but that turned out to be due to not inserting it deep enough. A small LED light will light up to indicate that the charging process is active.

The disadvantage is of course that your door lock is temporarily without power when you are charging, so you have to open the lock manually by turning it or inserting a physical key. But Nuki has thought of that too: you can temporarily connect a power bank to your door lock to charge it, so that you can still use the lock. If you have a power outlet near the door, you could even install a permanent power cable. Hence the two USB ports: whether the power outlet is on the left or right of the door, there is always a USB-B port on the right side. Alternatively, you can of course also use the original battery holder with a set of rechargeable batteries.

We have chosen to take the Power Pack out and charge it every few months. This can be done at night, for example, so that you are not bothered by it.

Fully charged, the Nuki Power Pack will last about a year on paper. If the battery status is below 20%, you will receive a notification from the Nuki app. However, the promised battery life of 12 months seems a bit exaggerated. We fully charged on May 20, 2021 and at the time of publishing this review (after 70 days), the battery charge had dropped from 100% to 70%. That is more than expected. If the battery drains linearly over the year, the battery charge should now be 80%. So it drains a bit faster than expected.

We don’t know if it really is linear. The Nuki app does contain a battery report, but it doesn’t show a graph with the status progression. The report does provide some other information that we weren’t aware of, such as having a stiff door and that our Nuki Smart Lock has to verify the Bluetooth connection more often than average. That’s something for us to figure out with which we can hopefully increase the battery life.

Conclusion Nuki Power Pack

At 49 euros, the Power Pack is not really expensive. If you want to save money, you can use rechargeable lithium or alkaline batteries, which you do have to replace more often. The Nuki Power Pack mainly offers convenience: if you have to charge every 9-12 months, that is easy to do. It is also more environmentally friendly and cheaper in the long run than using disposable batteries. A major drawback is the stock situation: the Nuki Power Pack has been sold out since its introduction, so you have to act quickly if you see one in stock somewhere.

Of course you also need a Nuki Smart Lock, which costs around €200 (or €269,- including bridge). Available at the shops below or directly via Nuki Shop (€30,- discount with discount code REF7KTY6NB7XQ).

Also read our Nuki Smart Lock 2.0 review, of the accompanying smart door lock.