Since you have a floating charger, determine the specs of that charger to see exactly what type of battery, and how much battery capacity it will handle. Then buy accordingly, but with a bit of planning. A recent silent key friend of mine used such a charger along with a 200 amp hour marine battery from WalMmart to power his 50 watt 2 meter station full time. He was retired, and on the air a bit more than average. Nevertheless, he would consistently get 2 weeks of operating between charges. If you go with a battery of that much storage capacity, you must know and understand several things. #1. Improper handling of such a battery can easily be fatal. #2. improper handling can burn down your house. #3. Mostly for the two reasons just listed, but also for some hazzard conditions relating to poor ventalation during charging, do not keep the battery inside your house. Interstate Battery, and most other battery suppliers sell special container boxes for housing these batteries. Set it as close to your radio as possible, but out doors, in one of these weather proof boxes. My friend kept his on a porch that was just outside his shack, and used about 10 feet of very large red and black paired cable to get the power inside to an Anderson Power Pole box. There is now some interest in my area in using this type of setup along with a solar pannel. While this much battery may be more than you want, it is a serious way to keep a station available during a power outage, with or without the solar pannel.