LiFePO4 is a good choice, but watch the rail when fully charged. 4S string with some mfrs cells can exceed 15V; don't remember max V for K2.
Simple soln is to use a series diode(s) rated for your max current and with enough V drop. If you build your own pack, be sure to use a good BMS. 73, Steve KL7JT ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]

