The makers of the new LiFePO4 batteries recognized a market in replacing traditional Sealed Lead Acid (SLA) batteries. With a little help from some built-in electronics, they offer a technology that packs 30% more energy into the same form factor as a traditional 7 AH SLA battery at half the weight. With a life of 1000 to 2000 charge/discharge cycles to a much greater depth (80% vs. 50%), one LiFePO4 battery will replace about 10 SLA batteries, at a lower total cost — reducing the amount of waste at the landfill (LiFePO4 contains no hazardous material).
A LiFePO4 battery has an almost flat discharge voltage over during its 80% discharge cycle. Given the higher energy density, deeper discharge cycle, and sustained higher voltage, one 10 AH LiFePO4 battery can provide more radio time than TWO 7 AH SLA batteries. So twice the operating time at 1/4 th the weight. A ham’s dream battery! And did I mention that a LiFePO4 battery will hold most of its charge for a year! Beats having to recharge the SLA batteries every month.
Another perk of the LiFePO4 battery, at least the K2B12V10EB, is that you can charge it with folding solar panels and not worry about using a solar charge controller. For example, the Powerfilm F15-1800 30 Watt panel is almost a perfect match for a 10 AH LiFePO4 battery. It provides about 1.8 amps at 15.4 volts when operating under peak conditions. The battery will essentially clamp the panel voltage, and it will slowly rise until the battery is fully charged at 14.6 volts. Battery voltage will continue to rise slowly after that point. If left on the charger for days it is possible that the battery overcharge circuit might kick in, allowing the panel voltage to rise to its maximum open circuit voltage of 21 volts. But according to the application engineer that should not be an issue for the battery. Just be aware that you can’t use a LiFePO4 battery as a “load” to regulate the solar panel voltage. In other words, you don’t want to charge your battery with your radio hooked up at the same time. Of course, if you had a rig like the FT817, which has a built-in voltage meter, you could just observe the charge voltage and remove the panel if the voltage gets above 14.6 volts.