The speaker has a 400mAh battery. With this battery you can enjoy up to 10 hours in Bluetooth mode, at 60% volume.
It takes 2 hours to fully charge your Crow Speaker's battery. You can use a 5V/1.0A power supply, or connect it to a USB port on a PC.
When it is close to running out, the headphones will emit a warning sound. That is when you should charge your SPC Crow headphones.
Even so, if you connect an iOS device, you can see what the headphones' battery percentage is at each moment. If you use Android, you can check the battery level of your SPC Crow headphones through third-party apps.