Can You Use A Battery While Charging. To extend the continuous play time of the headset you can use an external battery pack connect a USB cable to a power source or use the official Elite Strap with battery. Can I charge my batteries from multiple sources at once.

However say you run your load at 300 watts for 4 hours per day. 15v may only get your batteries to 13V never getting a full charge into them. Charging is set to 80-90.
In other words you can keep the UE Boom 3 Bluetooth speaker running indefinitely.
However say you run your load at 300 watts for 4 hours per day. Using laptop while charging doesnt effect your battery life if the max. Answer 2 and the aforementioned laptop powering are JUST what you propose. Always disconnect the negative usually black lead first and reconnect it last otherwise you could end up getting a nasty shock when you touch the positive terminal.

