I have had some experience in this and have found the only reliable way is to detect the temp increase in the batteries. This is especially for NiMH which only show a very shallow inflection. The dicsussion on temp sensors from a few weeks ago was very relevant. jon --On Tuesday, September 23, 2003 8:21 AM -0700 John Ferrell wrote: > I use NiCad & NiMh batteries frequently in Radio Control Model Airplanes. > I find that often the charger s unable to detect the peak, especially with > NiMh. It is desirable to have a step down to trickle after a certain level > of over charge. Since my batteries are seldom fully discharged, I limit > the total charge to 120%. > > It works well for me. > > John Ferrell > 6241 Phillippi Rd > Julian NC 27283 > Phone: (336)685-9606 > johnferrell@earthlink.net > Dixie Competition Products > NSRCA 479 AMA 4190 W8CCW > "My Competition is Not My Enemy" > > > ----- Original Message ----- > From: "Diego Sierra" > To: > Sent: Tuesday, September 23, 2003 12:08 AM > Subject: [EE:] NiMH charger improvement > > >> Hi! >> >> I design my own a NiMH reflex charger. It stopped charging the batts >> using the -dV/dT technique. >> >> I am thinking in some improvements on it, so any advice would be welcome: >> >> -The psu is a 12V/2A regulated, so when it needs to charge few > batteries a >> lot of power is wasted. Could I use a switched psu with variable output >> depending on the number of batts? , maybe controlled by the PIC. >> >> -Say I need to charge 4 different batts, I connect all of them in > serie >> with the charger. If I monitorize the -dV/dT of each one I can disconnect >> each batt as they get charged, while still charging the others. In this > way >> the charging time will be reduced (roughly will be T instead of 4xT). >> >> Cheers, >> Diego. >> >> -- >> http://www.piclist.com hint: To leave the PICList >> mailto:piclist-unsubscribe-request@mitvma.mit.edu >> > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads