Please check if your Humminbird software is up to date. Humminbird released a software update so that you can change the “battery type” of the unit to work with lithium batteries.
Updates can be found at https://www.humminbird.com/support/software-updates
Also make sure you are selecting the correct unit for updates. Select “Ice Series’ if you are using a Helix Ice unit.
Once you have completed the update – navigate to “Settings” and select “Battery Type.”
Change the “Battery Type” to 11.1v Lithium NMC (see picture below).