I used a 4S1P 2200 mAh LiFePO4 pack inside my K2 for a long time, and charged it with the original BT2 charging circuit. The BT2 charged the pack slowly enough that it never got warm, even if charging was continued well past full charge for each of the LiFePO4 cells. Normally I just let it run over night and that was enough. Although this is not the ideal way to charge this chemistry, I found it worked well. After several charge/discharge cycles using the BT2 circuit to charge, I would remove the pack and do a proper balance charge with a charger intended for LiFePO4 cells, and found that all of the cells were still in good balance. I also did not find any significant drop in pack capacity over the 5 years and perhaps 30 charge cycles I used this method. I think it worked well because the charge and discharge rates in K2 service were gentle and not a stress on the cells.
Would it have been ideal to use a balance charger every time to charge the pack? Of course. Doing it the way I did, maybe I lowered ultimate useful life of the pack from 500 to 200 cycles (just a WAG), but even if I had come close to 200 cycles before I replaced the pack, I would have considered doing it this way a big success. YMMV, but this worked well for me. Now that I have a KX3, I don't take the K2 portable anymore, but it is still my favored base station. Chip AE5KA SOTA W5 Association Manager On Tue, Jul 5, 2016 at 9:31 PM, Don Wilhelm <donw...@embarqmail.com> wrote: > Johnny, > > While this is a good suggestion, given the age of the K2 and the lack of > engineering time for the Elecraft designers, I don't think it will be a > change coming from Elecraft. > > It is however a good suggestion to reduce the weight and operating time > for a portable K2/10. I think it would be a good mod for some enterprising > ham. I don't think an internal charging circuit board would be necessary. > Check out the direct battery connection on my website www.w3fpr.com - > Smartcharger for the K2. With a battery replacement, the Smartcharger part > is not relevant, but the direct connection to the battery is relevant. > > 73, > Don W3FPR > > On 7/5/2016 9:11 PM, Johnny Siu via Elecraft wrote: > >> Similarly, with the advance in battery technology, the lead acid battery >> in K2 should be now advanced to a LiFePo pack as well. There are ample >> space inside the K2 for installing a new charging circuit board. This will >> greatly reduce the weight of a battery powered K2 and give much longer >> operating period. >> >> > ______________________________________________________________ > 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 > Message delivered to lightdazz...@gmail.com > ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
