If using Hummbird Electronics in ice fishing mode, the default battery type will be 14.8v NMC. You will need to change these settings in the Humminbird menu to the proper lithium battery type you are using. 12.8V LFP etc. 

12.8V LFP Models: 7.5Ah, 15Ah, 20Ah

14.8V NMC Models: 19Ah, 32Ah

The following are estimated operating times from Hummbird's estimated power draw. Operating times may vary based on conditions and settings.

Ice 35 Flasher - 7.5Ah 38hrs - 15Ah 76hrs

Ice 45 Flasher - 7.5Ah 32hrs - 15Ah 64hrs

Ice 55 Flasher - 7.5Ah 32hrs - 15Ah 64hrs

Helix 5 Bundle - 7.5Ah 13hrs - 15Ah 26hrs - 19Ah 38hrs

Helix 7 Bundle - 15Ah 20hrs - 19Ah 29hrs - 20Ah 27hrs - 32Ah 49hrs

Helix 9 w/360  - 19Ah 9.8hrs - 32Ah 16.4hrs

Helix 9 w/Live  - 19Ah 9.8hrs - 32Ah 16.4hrs