Last winter I replaced my 12v bow thruster with a 24v unit giving me almost twice the thrust with twice the duration. Two AGMs were placed next to the thruster and I removed 30 feet of 4/0 cabling. As for the charging system, I have a Guest 20A (12v)charger capable of two banks. Each bank charges one battery. This was done at a very reputable yard and we had many discussions about it before the install. They do it all the time. It took many discussions because I had to get my head wrapped around it
before I could have it done.
No, it's not the most efficient system but it's inexpensive, simple, and it works.