Thanks for reaching out and welcome to the Bose Community Forums.
Great question! The Portable Home Speaker is able to support a maximum power input of 5 VDC, 3 A. Due to this, a fast charger would no be recommended as it may damage the speaker. A fast charger typically runs at 20V with 5A meaning it would be far too powerful.
However, the speaker does have up to an incredible 12 hours of battery with a 4 hour charge time. It also comes with the possibility to add a charging cradle. So the need to charge your speaker will be eliminated as it will always be fully charged. Just place the speaker onto the cradle at the end of each day, for another day of wireless listening.
Let me know if you have any questions.
Vicky W - Community Support
Thanks for getting back to us.
The Portable Home Speaker is built with a lithium-ion battery. This type of battery has a built-in auto-off feature when a full charge is reached to prevent the battery from being overcharged. Even while still plugged in, the battery level will have to drop below a certain point to trigger the charging again. Therefore, it will be safe to leave your product on the charging cradle, this will charge your speaker only when needed without damaging the battery.
Please let us know if you have any further questions.