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MatC
237854.  Fri Nov 30, 2007 11:13 am Reply with quote

Simple question with - I am fairly confident - an unsimple answer.

Those machines you can buy to recharge ordinary, non-rechargeable batteries: do they work? There’s an awful lot of them being sold, and there’s also an awful lot of people on the internet telling you they are impossible.

 
rjmyth
237972.  Fri Nov 30, 2007 4:32 pm Reply with quote

i to would guess at no. it would be like selling a cake. then eating it all and then getting a machine to give the cake back bit by bit. so unless its a brutality machine or one from over the machine to build anything thread....

 
Rudolph Hucker
237975.  Fri Nov 30, 2007 4:43 pm Reply with quote

They do actually work but with rapidly diminishing returns for the charge.
What you really need instead, is a simply constructed cardboard pyramid, which, if you wear your foil helmet at a jaunty angle, will also make it unnecessary for you ever again to buy razor blades.

 
rjmyth
238004.  Fri Nov 30, 2007 6:07 pm Reply with quote

???? im very confused. you mean theyll have handed and thrust many knives at you for being such an idiot wearing a foil helmut?

 
djgordy
238010.  Fri Nov 30, 2007 6:21 pm Reply with quote

What's the point of trying to recharge ordinary batteries? I've had AA and AAA chargers for years. I can get a packet of 10 AAA for £9.99 from Maplins (not the holiday camp, you fool) and a packet of 4 AA from the Everything A Pound shop.

 
rjmyth
238047.  Fri Nov 30, 2007 7:59 pm Reply with quote

well if your charging one hell of alot then a recharger would be good however just get normal rechargable batteries instead

 
Rudolph Hucker
238053.  Fri Nov 30, 2007 8:11 pm Reply with quote

rjmyth wrote:
well if your charging one hell of alot then a recharger would be good however just get normal rechargable batteries instead


That is absolutely excellent advice.

 
MatC
238102.  Sat Dec 01, 2007 5:40 am Reply with quote

djgordy wrote:
What's the point of trying to recharge ordinary batteries? I've had AA and AAA chargers for years. I can get a packet of 10 AAA for £9.99 from Maplins (not the holiday camp, you fool) and a packet of 4 AA from the Everything A Pound shop.


djgordy, are you saying that rechargeable batteries actually work these days? I used to use them in the 80s and 90s and, frankly, they were poor. Perhaps they’ve improved during this century? If so, I might give them another go.

As for the question “why recharge disposable batteries?” ... well, I would’ve thought that was fairly obvious: there can’t be many homes in this country that don’t contain at least some such batts (especially the sizes that can’t be had as rechargeable) and it’s (isn’t it?) self-evidently better to reuse than to recycle?

 
djgordy
238193.  Sat Dec 01, 2007 2:09 pm Reply with quote

I find rechargeable batteries to be excellent. I use them in MP3 players, digital camera, clocks etc. There is a greater initial outlay which probably puts people off but they pay fro themselves over and over again. It is possible to buy trickle chargers which work from a solar panel or you can get chargers which plug into your car cigarette lighter.

There are some uses for which they are still not useful and probably never will be. I wouldn't use them for torches or on my cycle lights.

 
mckeonj
238224.  Sat Dec 01, 2007 5:17 pm Reply with quote

Is it really so that you can make a battery with a piece of fruit and a couple of coins. I've often seen this illustrated, but has anyone actually done it?
Apart from Signor Volta of course.

 
rjmyth
238249.  Sat Dec 01, 2007 6:12 pm Reply with quote

indeed. i have made many clocks and lights work from odd batteries in my chemistry classes and house. lemons potatoes, generaly anything even slightly acidic, including water but may not quite be powerful enough to operate anything big or visible enough apart from a meter.

the discs can be one of any metal qhich conducts electricity, we used copper and aluminium i think it was, basically the copper becomes the positive rod and attracts all the positive charge and the other more resstant one becomes negative.

 
mckeonj
238254.  Sat Dec 01, 2007 6:39 pm Reply with quote

Signor Volta's original battery was a pile of discs; diffeing metal plates with vinegar soaked cloth between - this was termed a 'voltaic pile', which is why the French word for battery is 'pile'.
Anyway, moving on, I was thinking about this, and about the 'electric eel', whose 'battery' is a pile of differing tissues; and I wondered whether one could construct an 'electric sandwich' of differing edible substances, such as pickled gherkins, which would deliver a mild electric shock when bitten. I remember 'tasting' batteries when young, the best ones for tasting were the old 4.5 volt flat jobs with the two brass tags on top.

 
Rudolph Hucker
238284.  Sat Dec 01, 2007 8:53 pm Reply with quote

rjmyth wrote:

Quote:
the discs can be one of any metal qhich conducts electricity


Don't they all do that? Conduct electricity that is - I thought that conductivity was one of the properties defining a substance as a metal.

 
rjmyth
238476.  Sun Dec 02, 2007 8:47 pm Reply with quote

no not all metals conduct electricity. but the main point is that none of them conduct (as far as i remember) exactly equal amount so whichever is less conductive gets a negative charge and the more conductive (usually copper) becomes positive and thus allows the flow of electrons from negative to positive. a bit of general ignorance there for you. most people believe its positive to negative but this is overlooked. as electrons are negatively charged they are initially repelled by the negative charge and then speed up further when attracted b the positive.

however there are circumstances where the electrons can actually flow both ways, such as when hooked up to a bettery recharger.

 
Rudolph Hucker
238498.  Mon Dec 03, 2007 4:19 am Reply with quote

rjmyth wrote
Quote:
no not all metals conduct electricity.


[url]http://hyperphysics.phy-astr.gsu.edu/hbase/solids/metal.html [/url]says:


Quote:
Description of Metals
A solid is considered to be a metal if it has high electrical and thermal conductivity. The chemical definition of a metal also includes having a characteristic surface luster or shine. It is characteristic of metals that they are malleable (can be hammered into sheets) and ductile (can be drawn into wires). A glance at the periodic table will show you that the majority of pure elements are metals. All metals except mercury are solids at room temperature.
Both the high electrical conductivity and thermal conductivity come from the fact that one or more valence electrons is relatively free to travel throughout the solid material. This connection is formalized in the Wiedemann-Franz law.



Which are the ones that are non-conductive then?

 

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