If you get a battery other than a lithium ion, such as a gell cell, which I have found works great and are sold at a good price, I sure would get a 10 watt solar panel and charge controller to go with it.
I know you said you didn't care for solar, but having a panel charging the battery all of the time keeps the voltage of the battery up for a far longer time. Much depends on how much you transmit. The other advantage to having your battery stay at a higher voltage is that the transmitter will put out a higher signal for a longer time and in many cases, the battery does not run down to a lower voltage which is what can kill batteries. Some transmitters start acting funny or quit working at 12 volts or below also. If you don't discharge a 12 volt battery below 11 volts or 10.5 at the very lowest, they will last a long time. Proper charging as well as discharge affects battery life.
The solar panels are also good for camping. You can use your radio for days with one and during an extended power outage, you can keep your radio on the air.
E Bay has good panels cheap or you can look for one of the flexable one's that roll up. They cost a lot more, but are very light weight and easy to pack.
I wouldn't get less than a ten watt panel. You can use a 5 watt, but they really are not enough. If you have the space and are not packing in, a 20 watt is even better, just be sure to use a charge controller. They don't cost much and solar panels put out about 18 volts, so a controller is a good thing to have and it will not allow the battery to overcharge.
I think most of the battery questions have been answered. I won't use a lithium Ion battery because they do blow up or catch fire sometimes, not worth the risk. The smaller gel cell are the way to go for me anyway. I use two 7.5 amp hooked up parallel or just one if it's going to be a short time on the radio for QRP. You can go larger for longer operating times.
73's John KF7VXA
