The HomePod mini is a more portable version of Apple's HomePod, but that doesn't make it a portable smart speaker. Since it needs power and wifi to work, people usually plug in their HomePod mini to a wall socket and let the speaker live in the same spot. But you actually could move your HomePod mini around the house and treat it like a portable speaker for your home—that's exactly what the folks at MacStories have done to their HomePod mini, which they aptly call the RoamPod.
How to use the HomePod mini as a portable speaker
Their idea is simple: Buy a HomePod mini accessory with a built-in battery pack and use that to make the device portable. If you could take the HomePod to whichever room you're in, you might not need to buy additional speakers for your home, including additional HomePod minis—the one you have just moves around with you.
To make your HomePod mini "portable," you'll need a battery base, and you have two options: You can either get the Mission Battery Base ($42 at the time of writing) or the PlusAcc Battery Base ($44 at the time of publishing). The Mission Battery Base has better reviews on Amazon, but you should take a look at the reviews yourself before making a decision. Buyer reviews say the PlusAcc product muffles the sound and has shorter battery life, both of which could be dealbreakers. Once you choose an accessory, it's pretty much plug-and-play. You can enjoy great sound quality, the HomePod mini's ability to play directly from Apple Music, or send any audio to the speaker via AirPlay.
The limitations of a portable HomePod mini
Having said all that, the HomePod mini can be a frustrating product to own. When it works, it's great, but if it malfunctions, solutions aren't always easy to come by. If you have a home with multiple wifi routers or networks, you never really know which one the HomePod mini will latch on to. Sometimes it connects to a weaker signal and performs poorly, and the best you can do is restart and try again.
You may be tempted to take the HomePod mini with you during your travels, but it's not a good idea. The speaker needs wifi to work, and finding a stable wifi connection is a challenge when you're traveling. A Bluetooth speaker will serve you far better than the HomePod in that case. Your "portable" HomePod mini may not deliver the best battery life either, with reports of 4-8 hours of music playback being fairly common on the battery bases we've linked to. That means charging is another thing to worry about fairly frequently when you're on the go.