The particular brand of Lithium Ferro Phosphate battery that I got has the brand name A123. That company talks about "nanophosphate" which presumably means that some kind of nanotechnology is used, which may lead to higher load current capacity. In any case, the Buddipole website and the specification sheet show discharge curves for up to 40 A loads, and I believe that refers to a single 3.3 V cell of 2.3 AH capacity. The output voltage is a little lower at those high load currents; the flat portion of the curve is at about 2.8 V when the load is 30A. Maximum continuous discharge current is specified as 70 A. Life is specified as 1000 cycles at 10C. As many as 7000 cycles are said to be possible when the load is 1C.
73, Erik K7TV Leigh wrote: Yes, LiFePO4 has a high power density but not as high energy density as LiPoly or the typical Li-Ion (laptop) batteries. It was chosen for the One Laptop per Child project, for example. The chemistry has a very flat discharge curve, and sources high current or low current, and retains its efficiency. For SLA, the capacity is rated at a discharge rate of 1/20 C, so a 7AH SLA battery will give you 1A for 7 hours, but any transmit at 20A would be well beyond its capacity. A 20AH SLA would give you 1A for 20 hours, and could give you 20A briefly, but not for 1 hour. But an 8AH LiFePO4 will have no trouble giving you 20A for 20-25 minutes solid key down. With SSB 40% modulation at 100W and transmitting 1 minute out of 4, that gives you 10% duty cycle, and because of the excellent properties of LiFePO4 you'd get a a couple of hours of operating time easily, especially with the low RX current draw of the KX3. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
