Brian, The consideration over the bulk charge rate is still valid - if the charger goes into bulk charge state the voltage is higher - AND, if the receive current is much lower than the bulk charge current, the battery can be over-charged. To prevent that condition, the bulk charge rate should be lower than the receive current (it does not have to be matched to the receive current - just lower).
What will happen is that part of the receive current will come from the charger and some from the battery - all is well as long as your operating times are only for a few hours, the battery will provide plenty of "juice". The switchable Smartcharger is a real help here, but I would suggest using 1 amp for the higher current rate - provided you resolve to leave it at the low current rate until your operating session exceeds 2 or 3 hours, and at that time, switch the charger to the 1 amp rate. If you cannot make that resolution, then I would suggest your proposed 250/500 ma combination would be better. 73, Don W3FPR On 5/8/2011 8:02 PM, Brian - N5BCN wrote: > Hi all, > > A&A Engineering's "QRP Smart Charger" has the option to be built using two > of the four charging rates: 0.250 A, 0.500 A, 0.750 A, and 1.00 A. I plan > to run my K2 using a KBT2 + Charger combo. > > Which two charging rates would be suit this setup? My K2 has a number of > options and draws about 380 mA right now on receive, considerably more when > the remoted KPA100 goes into high power mode (remoted KPA100 obviously runs > on a different power source). > > I've read W3FPR's Smart Charger Mod and he's using 250 mA, so I'm leaning > towards the 250 mA/500 mA combo, however, I don't think his mod is used in > conjunction with a remoted KPA100. > > 73 > > N5BCN - Brian > > ----- > K2 #6800 KPA100/KAT100-2, KSB2, KAT2, KIO2, K160RX, KNB2, KAF2, LP-PAN/K2 w/ > Pre-amp, SignaLink USB > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/A-A-Engineering-Charger-KBT2-tp6342835p6342835.html > Sent from the Elecraft mailing list archive at Nabble.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 > ______________________________________________________________ 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
