TLDR: For home use, a heavy and less costly 100Ah deep cycle battery that would not need to be moved around will work fine for a short term power outage and blasting away with 5W. It will also enjoy all the fast charging you can give it when the power comes back on. Even with simplex use, I would use 5W and "step it up" to 10, 20 and maximum 40W if needed temporarily. Your battery life will thank you later.
Anyways...
I have definitely not come across a 100 Ah LiFePO4 battery for a bit over $100. I would not purchase one for that price if I found it, unless thousands have travelled that road ahead of me and confirmed the specs through testing and use.
A LiFePO4 battery "may" be able to charge/discharge at 1C, but the overall lifespan/charge cycles will be reduced. A LiFePO4 that is charged/discharged at a 0.2C rate ( not 1C ) will probably last the thousands of cycles the MFG. notes about the particular battery. This is a case of just because you can, does not mean you should go full bore scenario (you know who you are). That noted, a 100Ah LiFePO4 battery would handle an HF radio using 100W on phone just fine. Also, 400W of solar panels in full sunlight may produce around 20A going through a LiFePO4 solar controller, which would be ideal for a 100Ah LiFePO4 battery as that is close enough to a 0.2C rate. One could transmit using 100W FM for probably four hours continuously. I would not do that with a deep cycle acid battery.
The advantage of the LiFePO4 is not worrying about destroying the battery as well as being able to use more amp hours out of it because of the BMS (Battery Management System) typically built into the battery. The BMS will stop the flow of electricity until the battery is charged again. I task a 100W solar panel and a 32AH LiFePO4 battery to keep a 12v refrigerator running while camping. No problem during the day of course and it handles it fine from sunset to sunrise. I tested it with the battery and 12v cooler outdoors, but in the shade for several days. The temperature was over 105°F during the day and still plenty hot at night. I also opened and closed the cooler as one would do. It remained at 38°F no problem.
Anyways...
I have definitely not come across a 100 Ah LiFePO4 battery for a bit over $100. I would not purchase one for that price if I found it, unless thousands have travelled that road ahead of me and confirmed the specs through testing and use.
A LiFePO4 battery "may" be able to charge/discharge at 1C, but the overall lifespan/charge cycles will be reduced. A LiFePO4 that is charged/discharged at a 0.2C rate ( not 1C ) will probably last the thousands of cycles the MFG. notes about the particular battery. This is a case of just because you can, does not mean you should go full bore scenario (you know who you are). That noted, a 100Ah LiFePO4 battery would handle an HF radio using 100W on phone just fine. Also, 400W of solar panels in full sunlight may produce around 20A going through a LiFePO4 solar controller, which would be ideal for a 100Ah LiFePO4 battery as that is close enough to a 0.2C rate. One could transmit using 100W FM for probably four hours continuously. I would not do that with a deep cycle acid battery.
The advantage of the LiFePO4 is not worrying about destroying the battery as well as being able to use more amp hours out of it because of the BMS (Battery Management System) typically built into the battery. The BMS will stop the flow of electricity until the battery is charged again. I task a 100W solar panel and a 32AH LiFePO4 battery to keep a 12v refrigerator running while camping. No problem during the day of course and it handles it fine from sunset to sunrise. I tested it with the battery and 12v cooler outdoors, but in the shade for several days. The temperature was over 105°F during the day and still plenty hot at night. I also opened and closed the cooler as one would do. It remained at 38°F no problem.