When using a LiPo battery, you need to set a proper cutoff voltage for your battery as per its discharge C count and the load. The ESC will monitor the battery voltage all the time, LVC(Low Voltage Cutoff) protection will be activated and the output power will be remarkably decreased when the battery voltage goes below the programmed cutoff voltage.
How to calculate the cutoff voltage: cutoff voltage=cutoff voltage per cell * cell count. For instance, when setting the cutoff voltage per cell at 3.2V, the total cutoff voltage for a 3S Lipo should be 3.2V*3=9.6V.
After entering the Low-Voltage Cutoff Protection: when the LVC protection is activated, the output will be halved. That means the output power will be only 50% even at full throttle, the RED LED will flash slowly at the same time. Please get your boat back immediately when this happens and change another fully charged battery.
Warning! If you ignore the “hint” and keep using the battery will get your battery irreversibly damaged.
When using a NiMH battery: because NiMH batteries don’t need this LVC protection, so you can set the “Cutoff Voltage” to “Disabled”. When you find the power is remarkably decreased in sailing, you only need to get the boat back immediately.