If you are looking for a small Bluetooth speaker while riding your ebike I may have found the perfect solution. I recently purchased the Noxgear 39g Wearable Bluetooth Speaker from Amazon for around $60 bucks.
The controls are super simple to turn on, accept a call and adjust volume. I like how it can clip on to your pocket or uses the included magnetic clip so you can locate it anywhere on your clothing.
Battery life is great. It has a robust rechargeable battery yielding up to 12 hours of continuous play on a single charge.
The mini Bluetooth speaker dishes out studio-quality sound with its N52 neodymium audio driver. Enjoy crystal clear phone calls with its active noise suppression feature. Its also lightweight at just 39 grams.