Yes, on  Gen 1.5  and Gen 2 Turtleboxes there is a 5-step battery level indicator that shows the current battery life in 20% increments.   It works similar to a fuel gauge, for instance:
- When not on the charger, if 4 of the 5 lights are lit, the Turtlebox has about an 80% charge.
- When connected to the charger, if 3 lights are solid and the 4th is blinking, the Turtlebox has about a 60% charge.  When the Turtlebox is fully charged, all 5 lights will be solid.

Gen 1.5

Gen 2