The MarkSetBot comes with a 100Ah 12v Lithium-Ion battery (older Bots came with 50Ah and the values below are roughly half).
The battery will power the MarkSetBot for 24 hours in normal conditions (8-10 knots of breeze, 1-2 foot waves). These numbers can be dramatically decreased if there is a lot of current (.5knts+) or if the Bot is instructed to motor itself out to the racecourse. The Bot is able to handle current and motoring out to the course, but both reduce battery life. As an example, in 1 knot of current with 20 knots of breeze, the 100Ah battery would likely give you 5 to 8 hours of battery life.
When in the MSB app, you can see battery voltage, battery % remaining, and battery Amp Hours remaining. You find that information by clicking Menu, then Battery.
Battery percentage remaining also can be tested with a voltmeter using the following chart:
100% ==> 14.3 V
80% ==> 13.28 V
60% ==> 13.14 V
40% ==> 13.106 V
20% ==> 12.89 V
NOTE: these readings need to be done when there isn't load. Be sure the prop is not spinning when testing.