Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK? Or is there something terrible that
can happen?

Cheers
John

Another John wrote:

Surely rechargeables would be OK?

8x 1.5V alkali will give the bins 12V, but NiMHs will be closer to 9.6V

Or is there something terrible that can happen?

They might complain about flat batteries a lot earlier

On Sun, 09 Jun 2019 08:34:18 +0100, Another John
wrote:

Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK? Or is there something terrible that
can happen?

Cheers
John

Yes.

The internal resistance of NiMh batteries is very low. High current
devices, flashguns in particular will be seen as almost a dead short
by a battery, An NiMh or a NiCad can deliver a lot of Amps from a
fully charged cell.

If the device is not yours, follow the instructions.

AB

"Another John" wrote in message
...
Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK? Or is there something terrible that
can happen?

Cheers
John

lower voltage so no good ...

"Jim GM4DHJ ..." wrote in message
...

"Another John" wrote in message
...
Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK? Or is there something terrible that
can happen?

Cheers
John

lower voltage so no good ...

....or am I thinking about ni-cads 1.2v ???/??...

On Sun, 9 Jun 2019 09:43:24 +0100, "Jim GM4DHJ ..."
wrote:


"Jim GM4DHJ ..." wrote in message
...

"Another John" wrote in message
...
Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK? Or is there something terrible that
can happen?

Cheers
John

lower voltage so no good ...

...or am I thinking about ni-cads 1.2v ???/??...


Voltage shouldn't be too important within reason. Any device that
stopped working at 1.25 V would "waste" a lot of bettery power with
Alkaline batteries.

Generally outdoor "toys" have to have a bit of resiliance regarding
Volts anyway, simply because low temperatures can drop the applied
Voltage anyway.

A low source impedance can mean disaster for equipment as a lethargic
oscillator will sink a lot of Amps.

AB

In article ,
says...

If the device is not yours, follow the instructions.

It's not as if it is going to cost you a fortune - Poundland
now sell 12 AA alkaline battery packs for £2.


--

Terry

---
This email has been checked for viruses by AVG.
https://www.avg.com

Don't be a cheapskate, your mate has lent you the bins the least you can do in return is put the correct batteries in and think of the brownie points the next time you want to borrow summat off him again!

Richard

On 09/06/2019 08:34, Another John wrote:
Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK? Or is there something terrible that
can happen?

It may well use an inverter to drive the EHT for the image tube. The
combination of low internal resistance and lower output voltage of
rechargeble batteries could kill it by over current. The same issue used
to affect cheap and nasty flashguns back in the old days (and may still
do so). They relied on the internal resistance of primary cells.

Cheap 1.5v Kodak cells are about £1 a dozen from Poundland or Wilko.
Just don't forget about them and leave them in the device for too long.
(that said most of the cells I have had leak recently were Duracell).

--
Regards,
Martin Brown

In article
,
Another John wrote:

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK? Or is there something terrible that
can happen?

OP he thanks so much for the advice! You've also answered a
subsidiary question, which is "are cheapo batts from Poundland etc good
enough?"

I guess at a pound a dozen or so, and when as many as 8 are needed, the
answer is "at a pound a go? what the heck!".

And thanks also, TrickyDicky, for reminding me of my responsibilities as
a mate! :-)

Cheers
John

Another John explained on 09/06/2019 :
OP he thanks so much for the advice! You've also answered a
subsidiary question, which is "are cheapo batts from Poundland etc good
enough?"

I guess at a pound a dozen or so, and when as many as 8 are needed, the
answer is "at a pound a go? what the heck!".

I tried them and they are quite useless, ended up bining them.

On 09/06/2019 08:48, Archibald Tarquin Blenkinsopp Esq wrote:
On Sun, 09 Jun 2019 08:34:18 +0100, Another John
wrote:

Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK? Or is there something terrible that
can happen?

Cheers
John

Yes.

The internal resistance of NiMh batteries is very low. High current
devices, flashguns in particular will be seen as almost a dead short
by a battery, An NiMh or a NiCad can deliver a lot of Amps from a
fully charged cell.

If the device is not yours, follow the instructions.

This.

I blew up the electronics in an "only use alkaline cells" camera by
using NiMh. A little discussion (either here or another newsgroup - I
don't remember) and it became obvious that the internal resistance of
the cells were critical to the performance and survivability of the
electronics. It was a 1980s camera so perhaps that design wouldn't have
been seen as so negligent in those days.

Nick

On 09/06/2019 20:40, Harry Bloomfield wrote:
Another John explained on 09/06/2019 :
OP he* thanks so much for the advice!** You've also answered a
subsidiary question, which is "are cheapo batts from Poundland etc good
enough?"

I guess at a pound a dozen or so, and when as many as 8 are needed, the
answer is "at a pound a go? what the heck!".

I tried them and they are quite useless, ended up bining them.

I've found Screwfix AA and AAA are OK, especially when on special offer

On Sun, 9 Jun 2019 21:31:50 +0100, newshound wrote:

On 09/06/2019 20:40, Harry Bloomfield wrote:
Another John explained on 09/06/2019 :
OP he* thanks so much for the advice!** You've also answered a
subsidiary question, which is "are cheapo batts from Poundland etc good
enough?"

I guess at a pound a dozen or so, and when as many as 8 are needed, the
answer is "at a pound a go? what the heck!".

I tried them and they are quite useless, ended up bining them.

I've found Screwfix AA and AAA are OK, especially when on special offer

Lidl's seem to be as good as most and, with luck, less chance of leaking
than the cheapos.
Toolstation has boxes that are quite cheap per cell.
--
Peter.
The gods will stay away
whilst religions hold sway

On Sun, 9 Jun 2019 21:28:11 +0100, Nick Odell wrote:

On 09/06/2019 08:48, Archibald Tarquin Blenkinsopp Esq wrote:
On Sun, 09 Jun 2019 08:34:18 +0100, Another John
wrote:

Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK? Or is there something terrible that
can happen?

Cheers
John

Yes.

The internal resistance of NiMh batteries is very low. High current
devices, flashguns in particular will be seen as almost a dead short
by a battery, An NiMh or a NiCad can deliver a lot of Amps from a
fully charged cell.

If the device is not yours, follow the instructions.

This.

I blew up the electronics in an "only use alkaline cells" camera by
using NiMh. A little discussion (either here or another newsgroup - I
don't remember) and it became obvious that the internal resistance of
the cells were critical to the performance and survivability of the
electronics. It was a 1980s camera so perhaps that design wouldn't have
been seen as so negligent in those days.

Nick

Could be voltage or internal resistance. I've a BP monitor that musn't have
NiMH - it has a little pump, so I expect the current would be too high.
Seems to me, in many cases, that the high-draw devices need the higher
resistance, e.g. so as not to overload a motor or, in the case of a camera,
the flash might be the critical circuit.
Oral-B toothbrush runs well on NiMH - one lasted just over 3 years, the same
as a rechargeable one that cost 3x as much. The Lidl equivalent needs the
higher voltage of alkaline.
I've a little Aldidl camera that's good on NiMH, so it's not all cameras.
--
Peter.
The gods will stay away
whilst religions hold sway

On 09/06/2019 22:24, PeterC wrote:
On Sun, 9 Jun 2019 21:28:11 +0100, Nick Odell wrote:

I blew up the electronics in an "only use alkaline cells" camera by
using NiMh. A little discussion (either here or another newsgroup - I
don't remember) and it became obvious that the internal resistance of
the cells were critical to the performance and survivability of the
electronics. It was a 1980s camera so perhaps that design wouldn't have
been seen as so negligent in those days.

Could be voltage or internal resistance. I've a BP monitor that musn't have
NiMH - it has a little pump, so I expect the current would be too high.
Seems to me, in many cases, that the high-draw devices need the higher
resistance, e.g. so as not to overload a motor or, in the case of a camera,
the flash might be the critical circuit.
Oral-B toothbrush runs well on NiMH - one lasted just over 3 years, the same
as a rechargeable one that cost 3x as much. The Lidl equivalent needs the
higher voltage of alkaline.
I've a little Aldidl camera that's good on NiMH, so it's not all cameras.

There's just too much "crying wolf" on this matter to know what to do.

--
Max Demian

On Sun, 9 Jun 2019 23:02:12 +0100, Max Demian wrote:

On 09/06/2019 22:24, PeterC wrote:
On Sun, 9 Jun 2019 21:28:11 +0100, Nick Odell wrote:

I blew up the electronics in an "only use alkaline cells" camera by
using NiMh. A little discussion (either here or another newsgroup - I
don't remember) and it became obvious that the internal resistance of
the cells were critical to the performance and survivability of the
electronics. It was a 1980s camera so perhaps that design wouldn't have
been seen as so negligent in those days.

Could be voltage or internal resistance. I've a BP monitor that musn't have
NiMH - it has a little pump, so I expect the current would be too high.
Seems to me, in many cases, that the high-draw devices need the higher
resistance, e.g. so as not to overload a motor or, in the case of a camera,
the flash might be the critical circuit.
Oral-B toothbrush runs well on NiMH - one lasted just over 3 years, the same
as a rechargeable one that cost 3x as much. The Lidl equivalent needs the
higher voltage of alkaline.
I've a little Aldidl camera that's good on NiMH, so it's not all cameras.

There's just too much "crying wolf" on this matter to know what to do.

Two courses: safe way or head up arse and cross fingers! :-
--
Peter.
The gods will stay away
whilst religions hold sway

On 09/06/2019 20:40, Harry Bloomfield wrote:
Another John explained on 09/06/2019 :
OP he* thanks so much for the advice!** You've also answered a
subsidiary question, which is "are cheapo batts from Poundland etc good
enough?"

I guess at a pound a dozen or so, and when as many as 8 are needed, the
answer is "at a pound a go? what the heck!".

I tried them and they are quite useless, ended up bining them.

They are fine if all you want is a moderate load for relatively short
periods of time. They are useless at high currents and I wouldn't trust
them not to leak if used for longer term in something like a clock.

--
Regards,
Martin Brown

On 10/06/2019 08:39, PeterC wrote:
On Sun, 9 Jun 2019 23:02:12 +0100, Max Demian wrote:

On 09/06/2019 22:24, PeterC wrote:
On Sun, 9 Jun 2019 21:28:11 +0100, Nick Odell wrote:

I blew up the electronics in an "only use alkaline cells" camera by
using NiMh. A little discussion (either here or another newsgroup - I
don't remember) and it became obvious that the internal resistance of
the cells were critical to the performance and survivability of the
electronics. It was a 1980s camera so perhaps that design wouldn't have
been seen as so negligent in those days.

Could be voltage or internal resistance. I've a BP monitor that musn't have
NiMH - it has a little pump, so I expect the current would be too high.
Seems to me, in many cases, that the high-draw devices need the higher
resistance, e.g. so as not to overload a motor or, in the case of a camera,
the flash might be the critical circuit.
Oral-B toothbrush runs well on NiMH - one lasted just over 3 years, the same
as a rechargeable one that cost 3x as much. The Lidl equivalent needs the
higher voltage of alkaline.
I've a little Aldidl camera that's good on NiMH, so it's not all cameras.

There's just too much "crying wolf" on this matter to know what to do.

Two courses: safe way or head up arse and cross fingers! :-

I'm an ignoramus on electronics but I can measure the current drawn by a
blood pressure monitor and calculate the likely effect of using
batteries with lower internal resistance but also lower voltage. So,
despite the manual having "Do not use rechargeable batteries", ours has
worked happily on NiMh got 6+ years.

There is perhaps a third course: ask yourself if the manufacturers are
just (a) covering their arse and (b) deflecting the prats who send stuff
back as faulty when it doesn't work 'cos they've stuck in flat batteries.

--
Robin
reply-to address is (intended to be) valid

On 09/06/2019 22:24, PeterC wrote:
snip
I've a little Aldidl camera that's good on NiMH, so it's not all cameras.


Oh yes. I agree. One of my other cameras has an option on the set-up to
choose alkaline or NiMh cells and adjusts the operation accordingly. I'm
sure lots of others do too.

Nick

In message , Archibald
Tarquin Blenkinsopp Esq writes
On Sun, 09 Jun 2019 08:34:18 +0100, Another John
wrote:

Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK? Or is there something terrible that
can happen?

Cheers
John

Yes.

The internal resistance of NiMh batteries is very low. High current
devices, flashguns in particular will be seen as almost a dead short
by a battery, An NiMh or a NiCad can deliver a lot of Amps from a
fully charged cell.

If the device is not yours, follow the instructions.

AB

I would not expect any normal electronic device to rely on the batteries
having a certain minimum internal resistance, and to disastrously
malfunction because it was 'too low'. I would have thought that it's a
case of 'the lower the better'.

As has been pointed out, the obvious problem is that rechargeable
voltages are lower than their non-rechargeable equivalents. I have a
camera and a DAB radio that both need at least 1.3V, and fully charged
Nicads and NiMHs (which rapidly drop to 1.2V) don't keep them going for
long.
--
Ian

On 10/06/2019 10:29, Ian Jackson wrote:
In message , Archibald
Tarquin Blenkinsopp Esq writes
On Sun, 09 Jun 2019 08:34:18 +0100, Another John
wrote:

Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK?Â* Or is there something terrible that
can happen?

Cheers
John

Yes.

The internal resistance of NiMh batteries is very low. High current
devices, flashguns in particular will be seen as almost a dead short
by a battery, An NiMh or a NiCad can deliver a lot of Amps from a
fully charged cell.

If the device is not yours, follow the instructions.

AB

I would not expect any normal electronic device to rely on the batteries
having a certain minimum internal resistance, and to disastrously
malfunction because it was 'too low'. I would have thought that it's a
case of 'the lower the better'.

If it is something that is regulated to deliver either constant power or
constant output voltage when the input voltage being too low combined
with the very low internal resistance of rechargeable cells results in
frying the device. Old cheap flashguns were very prone to this failure.

As has been pointed out, the obvious problem is that rechargeable
voltages are lower than their non-rechargeable equivalents. I have a
camera and a DAB radio that both need at least 1.3V, and fully charged
Nicads and NiMHs (which rapidly drop to 1.2V) don't keep them going for
long.

The things where damage can result are typically drawing a fairly large
current from the batteries and relying on their internal resistance to
limit the current into the device. It used to be quite a common trick.

Low current devices fail gracefully on rechargables with insufficient
voltage to drive the LCD display to decent contrast.

--
Regards,
Martin Brown

On 10/06/2019 10:29, Ian Jackson wrote:
In message , Archibald
Tarquin Blenkinsopp Esq writes
On Sun, 09 Jun 2019 08:34:18 +0100, Another John
wrote:

Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK?Â* Or is there something terrible that
can happen?

Cheers
John

Yes.

The internal resistance of NiMh batteries is very low. High current
devices, flashguns in particular will be seen as almost a dead short
by a battery, An NiMh or a NiCad can deliver a lot of Amps from a
fully charged cell.

If the device is not yours, follow the instructions.

AB

I would not expect any normal electronic device to rely on the batteries
having a certain minimum internal resistance, and to disastrously
malfunction because it was 'too low'. I would have thought that it's a
case of 'the lower the better'.

As has been pointed out, the obvious problem is that rechargeable
voltages are lower than their non-rechargeable equivalents. I have a
camera and a DAB radio that both need at least 1.3V, and fully charged
Nicads and NiMHs (which rapidly drop to 1.2V) don't keep them going for
long.

I've a couple of DAB radios that work fine on rechargeable NiMHs - about
the same life as alakali. Despite the manual saying not to use them.

Mind, a DAB radio isn't exactly high current. Nor I'd have thought the
OP's binoculars.

--
Cheers, Rob

Ian Jackson wrote:

In message , Archibald
Tarquin Blenkinsopp Esq writes
On Sun, 09 Jun 2019 08:34:18 +0100, Another John
wrote:

Hi chaps,

A friend has loaned me his infrared binoculars (Nightfox) for a few
days, but the batteries (Eight! AA) are dead.

I have a supply of rechargeables, but these are NiMH and the
instructions for the device say "please use only alkaline or lithium
batteries".

Surely rechargeables would be OK? Or is there something terrible that
can happen?

Cheers
John

Yes.

The internal resistance of NiMh batteries is very low. High current
devices, flashguns in particular will be seen as almost a dead short
by a battery, An NiMh or a NiCad can deliver a lot of Amps from a
fully charged cell.

If the device is not yours, follow the instructions.

AB

I would not expect any normal electronic device to rely on the batteries
having a certain minimum internal resistance, and to disastrously
malfunction because it was 'too low'. I would have thought that it's a
case of 'the lower the better'.

I would expect this problem to occur with equipment which needs a very
high input current, for instance to charge the capacitor in a flash gun
as quickly as possible for a given size of battery, and to get the best
possible result from alkaline batteries has no intervening circuitry to
limit the input current. It would presumably be fairly easy to design
it so that the highest possible current even from an outlier among
alkaline cells was ok. But then a new cell type with available short
term current 10 or more times higher might fry the input circuitry. I
have not seen this myself but it makes sense




As has been pointed out, the obvious problem is that rechargeable
voltages are lower than their non-rechargeable equivalents. I have a
camera and a DAB radio that both need at least 1.3V, and fully charged
Nicads and NiMHs (which rapidly drop to 1.2V) don't keep them going for
long.


--

Roger Hayter

In article ,
says...

Cheap 1.5v Kodak cells are about £1 a dozen from Poundland
or Wilko.

Presumably you are talking about zinc cardbon cells ...

Just don't forget about them and leave them in the device for too long.
(that said most of the cells I have had leak recently were Duracell).

Alkaline £1 for 5 or £2 for 12 at Poundland and I've never had
one of their Kodak branded alkaline cells leak.

They also have a guaranteed 10 year shelf life.

Never seen such low prices at Wilko.

--

Terry

---
This email has been checked for viruses by AVG.
https://www.avg.com

In article ,
says...

Another John explained on 09/06/2019 :
OP he thanks so much for the advice! You've also answered a
subsidiary question, which is "are cheapo batts from Poundland etc good
enough?"

I guess at a pound a dozen or so, and when as many as 8 are needed, the
answer is "at a pound a go? what the heck!".

I tried them and they are quite useless, ended up bining them.

No problems with their alkaline cells and, in the results of
life tests I've seen, they compare favourably with others -
including Duracell.

--

Terry

---
This email has been checked for viruses by AVG.
https://www.avg.com

Martin Brown wrote:
Low current devices fail gracefully on rechargables with insufficient
voltage to drive the LCD display to decent contrast.

Another reason for the 'no rechargeables' disclaimer might be the
self-discharge on NiMH. It's no good if an infrequently-used widget is
always flat when you come to use it - and the manufacturer will probably get
the blame for flattening the batteries.

These days we have low self-discharge NiMH so this problem is much less, but
perhaps the manufacturers still put the disclaimer in because people will
use non-LSD NiMH and then complain.

Theo

On Monday, 10 June 2019 14:15:53 UTC+1, Terry Casey wrote:
In article ,
says...
Another John explained on 09/06/2019 :

OP he thanks so much for the advice! You've also answered a
subsidiary question, which is "are cheapo batts from Poundland etc good
enough?"

I guess at a pound a dozen or so, and when as many as 8 are needed, the
answer is "at a pound a go? what the heck!".

I tried them and they are quite useless, ended up bining them.

No problems with their alkaline cells and, in the results of
life tests I've seen, they compare favourably with others -
including Duracell.

ZnC cells are cheap but their low capacity makes them far worse value. They also can't deliver enough current for some loads. With ZnC & alkaline, brand name has only minor effect on performance.


NT

newshound wrote :
On 09/06/2019 20:40, Harry Bloomfield wrote:
Another John explained on 09/06/2019 :
OP he* thanks so much for the advice!** You've also answered a
subsidiary question, which is "are cheapo batts from Poundland etc good
enough?"

I guess at a pound a dozen or so, and when as many as 8 are needed, the
answer is "at a pound a go? what the heck!".

I tried them and they are quite useless, ended up bining them.

I've found Screwfix AA and AAA are OK, especially when on special offer

I've had success with the yellow alkaline batteries from Home Bargains.