A good Bluetooth speaker will let you share music with friends. The best will also be easy to carry, offer useful features like waterproofing or long Bluetooth ranges, and sound better than others. To find our top picks, we consulted audio experts, looked across audiophile sites and consumer reviews, and then we tested 10 highly regarded speakers for portability, durability, and sound...

A recommended reading for all  rechargeable batteries users:
Coding Horror: Adventures in Rechargeable Batteries