Don, I'm sorry but I fail to understand why you think that the bulk charge mode will overcharge the battery.
Properly configured, the "smart charger" won't even completely charge the battery in the bulk mode, it takes a shift to the higher voltage absorption (overcharge) mode to completely "top off" the battery, after which the charger should reduce its output to the float voltage. The whole idea behind the smart charger is the automation of the charge cycle without intervention. The bulk mode current should be set by design to some fraction of the capacity (AH rating) of the battery and left alone. I have a homebrew charger keeping a 95AH Deka AGM battery charged and have operated my K3/100 on it 100% of the time for over two years. I built it using an A&A board in a modified Astron 35A power supply. http://k6mhe.com/n7ws/Astron_A_A.jpg Wes --- On Mon, 5/9/11, Don Wilhelm <w3...@embarqmail.com> wrote: > From: Don Wilhelm <w3...@embarqmail.com> > Subject: Re: [Elecraft] A&A Engineering Charger + KBT2 > To: "Brian - N5BCN" <n5...@yahoo.com> > Cc: elecraft@mailman.qth.net > Date: Monday, May 9, 2011, 12:16 PM > 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 > ______________________________________________________________ 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
