My anchor alarm and depth alarm work while my Garmin 7612 is in sleep mode.
I use a cellular iPad8 for anchor pro. Spend $7 per year to get all options on anchor pro. Make sure iPad is "cellular", so that you have gps tracking. There are no fees for gps tracking. Totally independent of a paid cell service plan. This iPad is also used for Navionics. My course is plotted every trip on iPad and 7612. One fails, I can still find my way without paper maps. Navionics works out of cell range.
iPad uses 2-5 watts
7612 uses 30 watts
iPhone 14 uses 1-3 watts
Leave iPad on boat when taking a dingy ride otherwise alarm goes off. Take cell phone in dingy for safety.
Leave iPad on charger while in use.
I got older refurbished iPad on Amazon for less than half price
