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OT: cordless screwdriver

Started by Pimpom March 9, 2013
Is anyone familiar with the cordless screwdriver in the link or a 
similar one? I'd like to know if using rechargeable 1.2V NiCd or 
NiMH cells instead of the specified 1.5V alkalines will result in 
a severely reduced torque.
http://www.ebay.com/itm/Black-Decker-6-Volt-Alkaline-4-AA-Battery-Operated-Cordless-SCREWDRIVER-NEW-/251240800353?pt=Power_Tools&hash=item3a7f1e6061 


"Pimpom"
> > Is anyone familiar with the cordless screwdriver in the link or a similar > one? I'd like to know if using rechargeable 1.2V NiCd or NiMH cells > instead of the specified 1.5V alkalines will result in a severely reduced > torque.
** The torque may well be better with rechargeable cells in use. Under heavy load, the voltage from alkalines drops significantly while the others hold up. .... Phil
Phil Allison wrote:
> "Pimpom" >> >> Is anyone familiar with the cordless screwdriver in the link >> or a >> similar one? I'd like to know if using rechargeable 1.2V NiCd >> or >> NiMH cells instead of the specified 1.5V alkalines will result >> in a >> severely reduced torque. > > > ** The torque may well be better with rechargeable cells in > use. > > Under heavy load, the voltage from alkalines drops > significantly > while the others hold up. >
Thanks, Phil. I need a handy cordless screwdriver, not the bulky heavy-duty drill-cum-screwdriver type. The one I had died some time ago and I'm weighing a built-in battery type against one using AAs - the convenience of the built-in type against the fact that the battery's likely to degrade in a few years and a replacement is not likely to be available to me.
On Sat, 09 Mar 2013 11:52:20 +0530, Pimpom wrote:

> Is anyone familiar with the cordless screwdriver in the link or a > similar one? I'd like to know if using rechargeable 1.2V NiCd or NiMH > cells instead of the specified 1.5V alkalines will result in a severely > reduced torque. > http://www.ebay.com/itm/Black-Decker-6-Volt-Alkaline-4-AA-Battery-
Operated-Cordless-SCREWDRIVER-NEW-/251240800353? pt=Power_Tools&hash=item3a7f1e6061 Not sure if the small difference in voltage would affect its operation but NiCd batteries would give much more torque than NiMh ones due to their lower internal resistance.
"asdf"
> > Not sure if the small difference in voltage would affect its operation > but NiCd batteries would give much more torque than NiMh ones due to > their lower internal resistance.
** There is simply no difference. NiMh cells matched NiCd in that respect long ago - but with much greater mAh. ... Phil
Pimpom Inscribed thus:

> Is anyone familiar with the cordless screwdriver in the link or a > similar one? I'd like to know if using rechargeable 1.2V NiCd or > NiMH cells instead of the specified 1.5V alkalines will result in > a severely reduced torque. >
http://www.ebay.com/itm/Black-Decker-6-Volt-Alkaline-4-AA-Battery-Operated-Cordless-SCREWDRIVER-NEW-/251240800353?pt=Power_Tools&hash=item3a7f1e6061 I've got one very similar that I put MiMH cells into. I've not noticed any slowdown. It does seem to weed out a poor cell very quickly, one getting discharged far faster than the others. -- Best Regards: Baron.
On Sun, 10 Mar 2013 00:06:51 +1100, Phil Allison wrote:

> NiMh cells matched NiCd in that respect long ago - but with much greater > mAh.
I experienced this difference myself years ago when swapping my mini kitchen vacuum cleaner old 1.6 Ah NiCd battery pack with a 2.1 NiMh one made with fresh store bought branded cells. The NiMh pack let the motor run a lot slower, albeit lasting much longer than the old NiCd cells, which is what one would expect by a fresh and more powerful current source having a higher internal resistance. Those NiMh cells once put back in other appliances worked fine for years, I still have most of them operating after about 10 years. Some searches brought similar results from other people along with the explanation: for power hungry devices NiCd cells are preferable due to lower internal resistance. I'm not aware of new developments in the field though, or about industrial grade batteries, only speaking of commonly available NiMh cells.

"asdf" <asdf@nospam.com> wrote in message 
news:khin75$obl$1@speranza.aioe.org...
> On Sun, 10 Mar 2013 00:06:51 +1100, Phil Allison wrote: > >> NiMh cells matched NiCd in that respect long ago - but with much greater >> mAh. > > I experienced this difference myself years ago when swapping my mini > kitchen vacuum cleaner old 1.6 Ah NiCd battery pack with a 2.1 NiMh one > made with fresh store bought branded cells. > The NiMh pack let the motor run a lot slower, albeit lasting much longer > than the old NiCd cells,
A while ago the NiCd cells in my shaver died and I couldn't find anywhere that still sells NiCd. While the NiMh cells I tried have about double the Ah capacity, they only ran the shaver about 1/4 - 1/3 of the length of time. It was fairly noticeable that the NiMh cells were getting fairly warm under load - so that's where all the energy was going! Unfortunately I'd bought a lot of early NiMh cells at good prices some time ago - apparently more modern ones have lower internal resistance.
On Sun, 10 Mar 2013 22:37:33 -0000, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

> > >"asdf" <asdf@nospam.com> wrote in message >news:khin75$obl$1@speranza.aioe.org... >> On Sun, 10 Mar 2013 00:06:51 +1100, Phil Allison wrote: >> >>> NiMh cells matched NiCd in that respect long ago - but with much greater >>> mAh. >> >> I experienced this difference myself years ago when swapping my mini >> kitchen vacuum cleaner old 1.6 Ah NiCd battery pack with a 2.1 NiMh one >> made with fresh store bought branded cells. >> The NiMh pack let the motor run a lot slower, albeit lasting much longer >> than the old NiCd cells, > >A while ago the NiCd cells in my shaver died and I couldn't find anywhere >that still sells NiCd.
--- http://www.batterybob.com/googlesearchresults.asp?cx=002871419911360800563%3A7eqzgsumivs&cof=FORID%3A11&ie=UTF-8&q=NiCd&sa=Google+Search ---
>While the NiMh cells I tried have about double the Ah >capacity, they only ran the shaver about 1/4 - 1/3 of the length of time.
--- Should've done your homework instead of ass uming that they were 1:1 replacements, huh? ---
>It was fairly noticeable that the NiMh cells were getting fairly warm under >load - so that's where all the energy was going!
--- But why? ---
>Unfortunately I'd bought a lot of early NiMh cells at good prices some time >ago - apparently more modern ones have lower internal resistance.
Perhaps. What can you tell us about the internal resistance of older NiMH cells with respect to newer ones? -- JF
Ian Field wrote:
> "asdf" <asdf@nospam.com> wrote in message > news:khin75$obl$1@speranza.aioe.org... >> On Sun, 10 Mar 2013 00:06:51 +1100, Phil Allison wrote: >> >>> NiMh cells matched NiCd in that respect long ago - but with >>> much >>> greater mAh. >> >> I experienced this difference myself years ago when swapping >> my mini >> kitchen vacuum cleaner old 1.6 Ah NiCd battery pack with a 2.1 >> NiMh >> one made with fresh store bought branded cells. >> The NiMh pack let the motor run a lot slower, albeit lasting >> much >> longer than the old NiCd cells, > > A while ago the NiCd cells in my shaver died and I couldn't > find > anywhere that still sells NiCd. While the NiMh cells I tried > have > about double the Ah capacity, they only ran the shaver about > 1/4 - > 1/3 of the length of time. > It was fairly noticeable that the NiMh cells were getting > fairly warm > under load - so that's where all the energy was going! > > Unfortunately I'd bought a lot of early NiMh cells at good > prices > some time ago - apparently more modern ones have lower internal > resistance.
NiCds are still easily available here in India - one of the "advantages" of being not as advanced as the West. If I decide to use NiMH types, they'll be Eneloops although, Ah for Ah, an eneloop costs twice as much as a NiCd. Can anyone point to a reliable comparison between Eneloops and NiCds regarding performance under load? Phil?