a_schwartz@vaxa.cc.uwa.oz.au (07/17/90)
I am having difficulty in getting a full charge into the battery which comes with my Zenith Supersport 286(20 mb hard disc). On three occasions in a row it has run out of juice after between 70 and 80 minutes use as a dumb terminal hooked up to the Vax I am now on, which involves no hard disc use after initial connection. The 286 is one year old; the battery has been drained and recharged perhaps a dozen times. Previous to these incidents, it has lasted for more than three hours of word processing, with lots of disc activity. A program called "Battery Watch" version 1:00(C) has been installed on the hard disc. It has a "Deep Discharge" feature which they claim will "discharge the battery as deeply as possible"..."in order to remove a memory-effect problem in a NiCad battery." I do not have the Battery Watch manual with me. The 286 owner's manual does not tell you exactly how to recharge the battery. When the 286 is on battery power, and the red power light blinks and the beeper sounds, I have tried to completely drain the battery in two different ways: (a)by running the machine until the screen goes blank and the power light goes out; and (b)by using the Battery Watch deep discharge feature to do the same thing. I have then attempted to recharge the battery (disconnected from the computer itself) by plugging in the power supply unit (model 150-308) which comes with the 286, and then plugging that into the mains overnight (16 hours the last time). This has worked in the past, but seems to work no longer. Can any Zenith or laptop mavens out there tell me: (a)What have I been doing wrong? (b)Can this battery be restored to taking a full charge, and if so, how? (c)Is the battery harmed by leaving it on the 286 and hooking up to mains power through it? (d)Just what is meant by "memory-effect" problems with nicads? And (e)Is there a Zenith dealer in Perth? Thanks in advance for the rescue.
goldberg@dtoa3.dt.navy.mil (Goldberg) (07/18/90)
In article <1990Jul17.131027.1976@vaxa.cc.uwa.oz.au> a_schwartz@vaxa.cc.uwa.oz.au writes: >I am having difficulty in getting a full charge into the battery >which comes with my Zenith Supersport 286(20 mb hard disc). On >three occasions in a row it has run out of juice after between 70 >and 80 minutes use as a dumb terminal hooked up to the Vax I am now >on, which involves no hard disc use after initial connection. >The 286 is one year old; the battery has been drained and recharged >perhaps a dozen times. Previous to these incidents, it has lasted for >more than three hours of word processing, with lots of disc activity. >A program called "Battery Watch" version 1:00(C) has been installed on the >hard disc. It has a "Deep Discharge" feature which they claim will >"discharge the battery as deeply as possible"..."in order to remove >a memory-effect problem in a NiCad battery." I do not have the Battery >Watch manual with me. The 286 owner's manual does not tell you exactly >how to recharge the battery. I also have a Zenith laptop with the same battery, which is now dead. I also took steps to discharge the battery and avoid memory effect. (Memory effect is when the battery "thinks" it has less capacity due to recharging when only partially discharged.) So you could say my battery now has amnesia! Anyway, I suspect the problem I have weas probably due to overcharging, which in turn was due to leaving the battery installed while unit was plugged into AC. Another possibility is lousy battery technology on the part of Zenith. Anyway, if and when I replace the nicad cells, I'll try the measure of disconnecting the battery when using AC.
ignatz@chinet.chi.il.us (Dave Ihnat) (07/19/90)
In article <1990Jul17.131027.1976@vaxa.cc.uwa.oz.au> a_schwartz@vaxa.cc.uwa.oz.au writes: >I am having difficulty in getting a full charge into the battery >which comes with my Zenith Supersport 286(20 mb hard disc). ... >on, which involves no hard disc use after initial connection. > ... >Can any Zenith or laptop mavens out there tell me: >(a)What have I been doing wrong? Probably not a lot. You shouldn't charge over about 12 hours, however. >(b)Can this battery be restored to taking a full charge, and if so, how? If you go through three full charge-deep discharge cycles (all the battery watch program is doing is activating all the peripherals it can to maximize current drain), and it doesn't recover, accept that you've a fatality. It happens... >(c)Is the battery harmed by leaving it on the 286 and hooking up to mains > power through it? I've never had a battery go bad by doing that--and I've had a Z-171, Z-181, and now a Supersport 286 20Mb. It *does* take a trickle charge while in use, though, so it's probably not a bad idea to drop it out of the circuit if you're using the machine all day, every day (or at least often.) >(d)Just what is meant by "memory-effect" problems with nicads? This is, believe it or not, a somewhat shaky assertion that has *not*, despite much rhetoric and "accepted wisdom", been reliably proven. It had been observed that some nicad batteries, if taken through a series of shallow charge-discharge cycles, tended to lose power much sooner than if taken through a full charge-discharge; and this reduced capacity seemed to reflect the levels that had been encountered in the shallow cycles. Thus, the warnings, and utilities to force deep discharge, etc. In point of fact, it was mentioned in an article I read a couple of weeks ago (sorry, I *don't* remember the 'zine; I read dozens, and it's in a stack at home) that this assertion has NOT been rigorously tested using a statistically meaningful sample of commercial batteries. (But, on the other hand, it costs little to follow the guidelines, and a lot if it *is* true and you scrag your battery.) >(e)Is there a Zenith dealer in Perth? Gee, sorry, can't help you there. I could pick one up here in Chicago and mail it to you...
brian@ankh.ankh.ftl.fl.us (Brian Mitchell Leach) (07/26/90)
> Anyway, I suspect the problem I have weas probably due to overcharging, > which in turn was due to leaving the battery installed while unit was > plugged into AC. Is it really possible to overcharge your battery? I frequently use my Toshiba T1000SE using AC power while the battery recharges at the same time. Once the battery gets a full charge, I thought it no longer draws power. Am I harming my battery if the unit is off, the AC adaptor is attached, and the battery is installed? ----- brian@ankh.ankh.ftl.fl.usa -- ----- brian@ankh.ankh.ftl.fl.usa