karsh@geowhiz.UUCP (Bruce Karsh) (11/09/84)
> [gobble gobble munch munch] > > I have recently bought a set of GE size 'D' rechargeable > batteries and have had to recharge them twice in the past month > and a half. When I first bought them, I charged them up, used I just bought a 9 volt nicad battery and found out that 9 volt nicads really only produce 7.2 volts. Thats fine for my application, but are there some common appliances which won't work with 7.2 volt nicads, but will work with regular 9 volt transistor batteries. -- Bruce Karsh --------------------------- Univ. Wisconsin Dept. of Geology and Geophysics | | 1215 W Dayton, Madison, WI 53706 | THIS SPACE FOR RENT | (608) 262-1697 | | {ihnp4,seismo}!uwvax!geowhiz!karsh ---------------------------
keithd@cadovax.UUCP (Keith Doyle) (11/12/84)
>> I have recently bought a set of GE size 'D' rechargeable >> batteries and have had to recharge them twice in the past month >> and a half. When I first bought them, I charged them up, used > I just bought a 9 volt nicad battery and found out that 9 volt >nicads really only produce 7.2 volts. Thats fine for my application, >but are there some common appliances which won't work with 7.2 volt >nicads, but will work with regular 9 volt transistor batteries. It's obvious that the battery manufacturers just can't bring themselves to produce a product that would effectively obsolete their disposable battery products. I remember some battery packs in some of the Tektronix scopes that seemed to last for years. Thinking that rechargables were practical because of this, I bought some Eveready rechargeables, AA, C, D, and 9 volt. The 9 volt is of course only 7.2 and won't work in some applications. I found that these batteries would recharge about 5 or 6 times before they wouldn't hold a charge. On the other hand, a friend of mine found some 9 volt type batteries some time ago that were made in Europe somewhere, that were actually 9.6 volts (or thereabouts) and held a charge much better then the Evereadys. I tried G.E's and Radio Shack (ugh!) out of desperation, but still found no success. My old T.I. calculator batteries hold up better than these. I've since resorted to building power supplies for many of my battery operated gizmos ( particularly musical instrument black boxes ), as I don't like to patronize these battery manufacturers. I've also heard that light bulbs that last forever can be made, but you can't buy them, because G.E. (etc.) would lose money. Keith Doyle {ucbvax,decvax}!trwrb!cadovax!keithd
klein@ucbcad.UUCP (11/16/84)
--------- [] About 5 years ago I bought some AA nicads for a Vivitar flash unit. They are still in the flash, although they now discharge themselves within a few days even when not used. For the first 3 years they performed superbly, requiring recharging only every month or two or after some large (> 100) number of flashes. Does anyone else have an experience like this, or has the quality gone way down? -- -Mike Klein ...!ucbvax!ucbmerlin:klein (UUCP) klein%ucbmerlin@berkeley (ARPA)
keithd@cadovax.UUCP (Keith Doyle) (11/21/84)
>So stop assuming bad karma from the battery makers until you understand >the technicals. I suppose they could stick in 7 cells ( 7 x 1.2 = 8.4 ) >but that's hard to do in two stacks. (There would have to be an odd cell >somewhere. Sometime pry apart a dead 9-volter to see what I mean...) >If they went to 8 cells ( 8 x 1.2 = 9.6 ) the OVERvoltage might burn out >something... I have no particular problem with the different VOLTAGE output of ni-cads, 9.6 volts (or even 8.4) is FINE as far as I'm concerned. Even 7.2 is better than nothing. I'm talking about the apparent (note: apparent) SHORT recharge life of average consumer ni-cads (I've experienced about a half dozen recharges and then they no longer hold a charge). I say apparent because I've yet to try the 10 ohm discharge trick. (But I will! I promise!) Keith Doyle {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithd "You'll PAY to know what you REALLY think!"
palisano@sunybcs.UUCP (Tom Palisano) (11/28/84)
> >> I have recently bought a set of GE size 'D' rechargeable > >> batteries and have had to recharge them twice in the past month > >> and a half. When I first bought them, I charged them up, used > > > I just bought a 9 volt nicad battery and found out that 9 volt > >nicads really only produce 7.2 volts. Thats fine for my application, > >but are there some common appliances which won't work with 7.2 volt > >nicads, but will work with regular 9 volt transistor batteries. > > It's obvious that the battery manufacturers just can't bring themselves > to produce a product that would effectively obsolete their disposable > battery products. I remember some battery packs in some of the Tektronix > scopes that seemed to last for years. The problem with NiCads is that by nature they only produce ~1.25 volts/cell as opposed to carbon cells @ 1.5 V/cell. NiCads also tend to have 'memory' with regard to how they were/are used. A battery that is recharged before it is fully exhausted will remember this and give limited service once charged. In addition NiCads are not ment to be used in a parallel combination due to their low internal resistance. These factors lead to problems when batteries of this type are used as replacements for standard non-rechargeable cells. Perhaps a better solution would be to use Lead-Acid cells that produce about 1.7-2.0 V/cell and have none of the quirks that a NiCad exhibits. Tom Palisano -- -- Tom Palisano uucp:[bbncca,decvax,dual,rocksanne,watmath]!sunybcs!palisano csnet:palisano@buffalo arpanet:palisano.buffalo@csnet-relay -- --