JBL Soundboost MotoMod

What is the functionality of the battery inside this mod? I have yet to see it change percentage regardless of what I do with my phone. When does it get used?
 
The Mod's Battey is only used when the Mod itself is being used. When you're playing music through the JBL MotoMod, it will start to use the battery inside the Mod. However, it won't use the Mod battery with just regular phone usage.
 
So it will run the JBL battery down to 0 then run off the phone battery when you are playing music?
 
Mine ran down to 10percent and wouldn't function anymore. It's still supposed to right?
 
Mine ran down to 10percent and wouldn't function anymore. It's still supposed to right?

Pretty sure it's supposed to be able to run off the phone's battery, but I haven't personally tested that. Maybe I've misunderstood, or been misinformed.
 
Pretty sure it's supposed to be able to run off the phone's battery, but I haven't personally tested that. Maybe I've misunderstood, or been misinformed.

The speaker is supposed to use its internal battery first, then when it's depleted, use the phone's battery.
 
At full blast i go 5 hours before mod batt is depleted. Turning it down to 80% extends a bit. Lower than 80 is useless. Are you guys roughly same playing time?