The first pack I had was a Lithium. They were expensive and replacement cells were impossible to buy. I have extensive experience with NiCads and several chargers from another hobby, RC airplanes. Other than the numbers, NiMh seems to behave similarly. I can validate the quality of each and the assembled pack. I was basicly "shotgunning" the problem. You understand the electronics better than I. BTW, If you choose to fabricate a NiMh fast charger, do not rely on detecting the voltage turn down to stop the process. It is easily missed and there should be some sort of limit on the total charge. The charger I use for RC batteries allows me to set the overcharge limit if the turn down is missed. I usually limit the charge to 120% of the batterry rating. John Ferrell http://DixieNC.US ----- Original Message ----- From: "Philip Pemberton" To: Sent: Tuesday, February 24, 2004 5:53 AM Subject: Re: TI Bq2014 problems > In message <005c01c3fa2c$092328b0$0402a8c0@xppro> > John Ferrell wrote: > > > I think that was the chip I encountered in an APC battery pack for my old > > Compaq 1237 Laptop. It uses a NiMh pack. > I kinda guessed that :) > > > The problem turned out to be > > getting the initial state of the battery to match what the chip expected. > That's the problem I've been having. I can get it to pick up that the battery > pack is totally kaputski, then it resets its registers and counts the charge. > What I don't get is why it never updates the LMD - this means that the "gas > gauge" display always displays around 80% when the battery is full. If LMD > was updating, the gas gauge would display 100% when the battery is full. > I guess I need to rig up a decent-sized battery pack. I've got four GP > "Industrial Rechargeable" (yes, the lime green ones) 150AAH AA-sized 1500mAh > batteries which shouldn't be too hard to build up into a pack. I've also > tracked down a 15W 0.1R resistor which should work quite well as a sense > resistor. It's bigger than one of the batteries! :-/ > > > I decided that one condition that should be expected was a battery that had > > shelf discharged. I removed the battery cells, cycled them a couple of times > > on a charger, > The catch: I don't have a charger that can fastcharge NiMHs. I've got one of > those black Made-In-China cheapie nicad chargers (branded "Calvin > Industrial", came from Maplin Electronics), but nothing that's specifically > for NiMHs. The fact that the GP batteries are tagged with no "nipple" really > doesn't help. > > > discharged them, reinstalled in the pack charged it in the > > computer, ran it down with the computer, recharged and it worked. I stopped > > there! > :) > So the trick is to cycle the individual cells a few times, then run them > flat, hook them up to the Bq chip and then cycle them again while the Bq is > hooked up and monitoring the cells? Makes sense to me. > %DEITY, these chips are picky. > > Thanks. > -- > Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB, > philpem@dsl.pipex.com | ViewFinder, 10BaseT Ethernet, 2-slice, > http://www.philpem.dsl.pipex.com/ | 48xCD, ARCINv6c IDE, SCSI > ... If it's not broke, let me take a crack at it. > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body