The single-piece product retails for £29.99 in the UK and €34.99 in Europe (it’s not yet listed in the US). That’s far cheaper than the only other solution for bringing your Technic models to life with Powered Up, 88012 Technic Hub, which retails for £74.99 / $89.99 / €79.99.
This is the first time the Powered Up battery box has been widely available in any capacity, having only appeared previously in a single set: 42113 Bell Boeing V-22 Osprey. That model was unfortunately cancelled just days before launch, and while a handful of copies found their way into the hands of collectors (before being exchanged for ludicrous sums of money), we’ve had to wait almost six months for 88015 Battery Box to arrive as a standalone product.
The new battery box lacks Bluetooth (the difference that allows it to come in considerably cheaper than 88012 Technic Hub), but you can still use it to provide power to your models, sidestepping the Control+ system that requires a smartphone to operate. For LEGO fans hoping to motorise their models without relying on apps, then, this is the way to go.
Veteran Technic fans will notice one distinct difference between 88015 Battery Box and its equivalent from Power Functions, the system that Powered Up replaced. While its predecessor could handle any number of motors up to its maximum voltage, the new box only allows two motors at a time. The good news is that both of those motors can be controlled by individual switches, which surely beats the single switch to operate all motors under the Power Functions system.