I saw an advert for a battery charger that claims to charge ordinary
batteries - primary cells. The specific ones shown in the ad were Duracells.
Are these chargers any good, or are they a waste of money? These batteries
say that they cannot be recharged. If this is true, how many times can it be
done?

After serious thinking Jake wrote :
I saw an advert for a battery charger that claims to charge ordinary
batteries - primary cells. The specific ones shown in the ad were Duracells.
Are these chargers any good, or are they a waste of money? These batteries
say that they cannot be recharged. If this is true, how many times can it be
done?

Primary cells can be recharged to some small extent, but their capacity
falls off rapidly with each recharge. There is also a risk of them
exploding due to pressure build up during charging - hence the warning.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Feb 27, 10:11*am, Harry Bloomfield
wrote:
After serious thinking Jake wrote :

I saw an advert for a battery charger that claims to charge ordinary
batteries - primary cells. The specific ones shown in the ad were Duracells.
Are these chargers any good, or are they a waste of money? These batteries
say that they cannot be recharged. If this is true, how many times can it be
done?

Primary cells can be recharged to some small extent, but their capacity
falls off rapidly with each recharge. There is also a risk of them
exploding due to pressure build up during charging - hence the warning.

Makes more sense to buy rechargeables.


NT

In article ,
"Jake" writes:
I saw an advert for a battery charger that claims to charge ordinary
batteries - primary cells. The specific ones shown in the ad were Duracells.
Are these chargers any good, or are they a waste of money? These batteries
say that they cannot be recharged. If this is true, how many times can it be
done?

As a child, when non-rechargable batteries were all zinc-carbon,
I discovered you could get a bit more use out of them if you
warmed them up in the oven.

About 25 years ago, I designed something which used one the Maplin
LCD temperature modules with high point and low point alarm outputs.
Life of the Zinc-carbon AA cell in these was a year, so what I did was
supply a charging current of about 20% more than the unit consumed.
It still has that same 25 year old zinc carbon battery in it, and
it still works - actually it's been running off it with no mains
power for almost a year now, as the item item was disconnected and
stuck in the garage.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
says...
As a child, when non-rechargable batteries were all zinc-carbon,
I discovered you could get a bit more use out of them if you
warmed them up in the oven.


I found you could exract the carbon rods and use them with a car battery
to make nice hot arcs. Make a pool of salt and you could smell the
chlorine once it started to melt and electrolyse. Never managed to
isolate any sodium, though.

--
Skipweasel - never knowingly understood.

In message , Andrew Gabriel
writes
In article ,
"Jake" writes:
I saw an advert for a battery charger that claims to charge ordinary
batteries - primary cells. The specific ones shown in the ad were Duracells.
Are these chargers any good, or are they a waste of money? These batteries
say that they cannot be recharged. If this is true, how many times can it be
done?

As a child, when non-rechargable batteries were all zinc-carbon,
I discovered you could get a bit more use out of them if you
warmed them up in the oven.

About 25 years ago, I designed something which used one the Maplin
LCD temperature modules with high point and low point alarm outputs.
Life of the Zinc-carbon AA cell in these was a year, so what I did was
supply a charging current of about 20% more than the unit consumed.
It still has that same 25 year old zinc carbon battery in it, and
it still works - actually it's been running off it with no mains
power for almost a year now, as the item item was disconnected and
stuck in the garage.

Wow!

I've just remembered that, in the 60s, I did somewhat similar with a
transistor portable radio. [It was a 'Realistic Seven' kit which I built
for my MIL.]

It was intended to run from a PP9 battery (the large 9V one), and took
around 15mA. While the battery lasted for quite some time, it was rather
expensive to replace. So, as the radio had loads of room inside, I added
a small internal small mains power supply.

To enable the radio still to be used portable (by simply by unplugging
the mains lead connector), I retained the battery, and arranged it to
trickle charge at a couple of mA. My MIL subsequently used the radio for
many years, and I don't recall the battery ever being replaced again.
--
Ian

On Feb 27, 2:43*am, "Jake" wrote:
I saw an advert for a battery charger that claims to charge ordinary
batteries - primary cells. The specific ones shown in the ad were Duracells.
Are these chargers any good, or are they a waste of money?

Compared to what? Compared to NiMH, they're not a good choice.

I used to recharge alkaline D cells years ago (commuting bike lights)
and it was a great improvement on what else was available at the time.
However NiMH have got so much cheaper since that there's no longer any
advantage to it.

Use a good intelligent charger though: Aldi, £13

On 27/02/2011 21:48, Andy Dingley wrote:
On Feb 27, 2:43 am, wrote:
I saw an advert for a battery charger that claims to charge ordinary
batteries - primary cells. The specific ones shown in the ad were Duracells.
Are these chargers any good, or are they a waste of money?
Compared to what? Compared to NiMH, they're not a good choice.

I used to recharge alkaline D cells years ago (commuting bike lights)
and it was a great improvement on what else was available at the time.
However NiMH have got so much cheaper since that there's no longer any
advantage to it.

Use a good intelligent charger though: Aldi, £13
I have the innovations charger and it is good. It will charge all
rechargeable and non rechargeable bats. Some better than others but then
if the normal battery wont recharge you have lost nothing as it was
flat anyway.

Gary

On Sun, 27 Feb 2011 21:22:35 -0000, Skipweasel
wrote:

In article ,
says...
As a child, when non-rechargable batteries were all zinc-carbon,
I discovered you could get a bit more use out of them if you
warmed them up in the oven.


I found you could exract the carbon rods and use them with a car battery
to make nice hot arcs. Make a pool of salt and you could smell the
chlorine once it started to melt and electrolyse. Never managed to
isolate any sodium, though.

I made a carbon microphone from a couple of those carbon rods: similar
to Example 1 in this drawing...
http://repo-nt.tcc.virginia.edu/clas...ges/carbon.gif

Nick

In article ,
Skipweasel writes:
In article ,
says...
As a child, when non-rechargable batteries were all zinc-carbon,
I discovered you could get a bit more use out of them if you
warmed them up in the oven.


I found you could exract the carbon rods and use them with a car battery
to make nice hot arcs.

I did that with a school friend. IIRC, it was triggered by an article
in Scientific American. It didn't use car batteries. I can't recall
what the article specified, but we worked up to using mains, and my
mum's 2.4kW electric kettle as a ballast. Probably should have been
using darkened/UV goggles or welding hood too, but didn't know that
then. I think we used sun glasses, and you couldn't look at the arc
anyway - it was far too bright.

My 2nd year university project required a carbon arc lamp (to use
the electrode as a 4000K black body emitter). The lab had a 220VDC
mains supply for such things, and it ran from that (I presume through
a resistor ballast, but I can't recall that now). It had proper
carbon arc rods though.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]