I've got loads of them. I'm sure I'm not alone. The thing is I no longer
know which adaptor came with what tool.


My questions:

If the adaptor fits the battery unit is it ok?

What if I use an adaptor which has a higher voltage than the battery rating
ie., adaptor has a 24v output and battery is 12v and conversely?

I don't want a fire or a ruined battery.


mark b

On Sat, 29 Jan 2005 23:27:48 -0000, "mark b"
strung together this:

I've got loads of them. I'm sure I'm not alone. The thing is I no longer
know which adaptor came with what tool.


My questions:

If the adaptor fits the battery unit is it ok?

No.

What if I use an adaptor which has a higher voltage than the battery rating
ie., adaptor has a 24v output and battery is 12v and conversely?

It won't instantly explode but it won't do them any good if they're
left connected for any period of time. Easy way to find ou, (usually),
is to match the voltages on the cells and chargers.
--

SJW
Please reply to group or use 'usenet' in email subject

mark b wrote:
I've got loads of them. I'm sure I'm not alone. The thing is I no longer
know which adaptor came with what tool.


My questions:

If the adaptor fits the battery unit is it ok?

What if I use an adaptor which has a higher voltage than the battery rating
ie., adaptor has a 24v output and battery is 12v and conversely?

I don't want a fire or a ruined battery.


I don't mean to be unkind, but this has to be a troll, right? Are you
really expecting the answer to be "yes, no problem, all chargers will
work fine with all batteries"?


--
Grunff

In article , Grunff
writes
mark b wrote:
I've got loads of them. I'm sure I'm not alone. The thing is I no longer
know which adaptor came with what tool.


My questions:

If the adaptor fits the battery unit is it ok?

What if I use an adaptor which has a higher voltage than the battery rating
ie., adaptor has a 24v output and battery is 12v and conversely?

I don't want a fire or a ruined battery.


I don't mean to be unkind, but this has to be a troll, right? Are you
really expecting the answer to be "yes, no problem, all chargers will
work fine with all batteries"?

Google groups by author is usually a laugh on suspect posters and yup
9/10 gasp posts really are genuine . . . . , v scary.
--
fred

"Grunff" wrote in message
...
mark b wrote:
I've got loads of them. I'm sure I'm not alone. The thing is I no longer
know which adaptor came with what tool.


My questions:

If the adaptor fits the battery unit is it ok?

What if I use an adaptor which has a higher voltage than the battery
rating
ie., adaptor has a 24v output and battery is 12v and conversely?

I don't want a fire or a ruined battery.


I don't mean to be unkind, but this has to be a troll, right? Are you
really expecting the answer to be "yes, no problem, all chargers will
work fine with all batteries"?


Actually there's a product around using a wind-up thing, presumably based on
the Bayliss clockwork radio, which claims to charge most things. How it
handles voltage and polarity I don't know - presumably some sort of sensing
electronics.

Mike wrote:

Actually there's a product around using a wind-up thing, presumably based on
the Bayliss clockwork radio, which claims to charge most things. How it
handles voltage and polarity I don't know - presumably some sort of sensing
electronics.

No, there would be no way to accurately determine how a battery pack
should be charged electronically.

With NiCds and NiMHs you need to charge them at a constant current, the
value of which is dependant on a) how fast you want to charge them and
b) their capacity. Furthermore, you need to control the length of time
for which you charge them.

I can provide more info if required, but this is textbook stuff which
can readily be looked up.


--
Grunff

In article ,
Grunff wrote:
No, there would be no way to accurately determine how a battery pack
should be charged electronically.

Think you can, by measuring the rate of current change, etc.

--
*Women like silent men; they think they're listening.

Dave Plowman London SW
To e-mail, change noise into sound.

I don't mean to be unkind, but this has to be a troll, right? Are you
really expecting the answer to be "yes, no problem, all chargers will work
fine with all batteries"?

Grunff

Well I wasn't intentionally trolling.
Anticipated answers more useful than this one might have suggested that a
12v charger won't charge a 24v battery or will take 10 days, or maybe an
over rated charger might do it more quickly but if you forget about it
something goes bang. Obviously matching battery to original charger would be
ideal but in reality I have found the chargers not to be branded as per the
tool.
I don't know how battery chargers interact with differing batteries so I
asked the question. Isn't that the reason for being of this Newsgroup,
people ask what they don't know and those who do know answer and vice versa.

When I get to know everything about everything as you clearly do I will be
able to advise accordingly and not delight in smug and arrogant answers.

Thank you

mark b

mark b wrote:

Well I wasn't intentionally trolling.
Anticipated answers more useful than this one might have suggested that a
12v charger won't charge a 24v battery or will take 10 days, or maybe an
over rated charger might do it more quickly but if you forget about it
something goes bang. Obviously matching battery to original charger would be
ideal but in reality I have found the chargers not to be branded as per the
tool.
I don't know how battery chargers interact with differing batteries so I
asked the question. Isn't that the reason for being of this Newsgroup,
people ask what they don't know and those who do know answer and vice versa.


Hey - no need to get so offended. Like many people on this group, I've
been caught out answering silly questions posted by trolls in the past.
Kind of makes you cautious.

A 12V charger won't charge a 24V battery, ever. A charger intended to
charge 24V batteries will destroy a 12V battery pretty quickly. A 14.4V
charger could be used for charging 12V batteries, but whether it will
damage them depends on how good a charger it is.



When I get to know everything about everything as you clearly do I will be
able to advise accordingly and not delight in smug and arrogant answers.

If you look at my posting history it will become quite clear to you that
I certainly don't know everything about everything, nor do I think I do.


--
Grunff

Dave Plowman (News) wrote:

Think you can, by measuring the rate of current change, etc.

Ok, let's explore that further. Imagine you have a black box, containing
a NiCd battery. You know the following:

- it could contain 2-20 cells in series
- they could have capacity between 1.2-3.6 AH

What voltage would you apply initially, and what would you do after
you've measured the initial current?


--
Grunff

Grunff wrote:

Ok, let's explore that further. Imagine you have a black box, containing
a NiCd battery. You know the following:

- it could contain 2-20 cells in series
- they could have capacity between 1.2-3.6 AH

What voltage would you apply initially, and what would you do after
you've measured the initial current?

That is actually straight forward, and would be handled by a decent
constant current delta peek charger.

The voltage is not actually relevant since a constant current supply
will modulate this so as to achieve the selected current (i.e. charge
rate). Monitoring the applied voltage should show a slight rise with
time, with a peek and then a decline as the pack reaches full charge.
The delta peek detector will sense this and turn off (or reduce) the
charge current at that time.

(I built a charger years ago from some spare bits I had. It is basically
a linear PSU with 40V DC output, and it uses a thick film hybrid IC
constant current/voltage regulator (a "L200" IIRC) configured in
constant current mode. A rotary switch selects one of a number of
presets that control the required current, the current regulator drops
the required voltage to match pack attached. No delta peak on my one
though, perhaps I will save that for an enhancement ;-))


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

mark b wrote:

Anticipated answers more useful than this one might have suggested that a
12v charger won't charge a 24v battery or will take 10 days, or maybe an

It is unlikely to charge it at all... but see anon.

over rated charger might do it more quickly but if you forget about it
something goes bang. Obviously matching battery to original charger would be
ideal but in reality I have found the chargers not to be branded as per the
tool.

No guarantee that the original charger will be "best" for the tool either!

One area where there is a huge variation in quality between different
tools, is in their batteries and also their chargers. It is possible to
build very good universal chargers that will fast charge an arbitrary
number of cells (i.e. different pack voltages) without any apriory
knowledge of the pack voltage, and also stop charging it at the right
point. (Makita usually ship a charger that will do just this - it is
quite happy to charge a 9V or a 18V pack without damaging either).

It is also possible to build a "charger" that is nothing more than a
transformer, single power diode, and a limit resistor! This will stick
half wave rectified DC through cells at a varying current. If limited to
low charge rates, this will actually work OK even though it is not the
"right" way to charge a NiCd at all. Scale up the power however, and it
will toast a cell in no time.

I don't know how battery chargers interact with differing batteries so I

The poor ones don't, better ones use delta peak detection, and/or
thermal detection.

asked the question. Isn't that the reason for being of this Newsgroup,
people ask what they don't know and those who do know answer and vice versa.

yup... don't get too bent out of shape one flippant remark though, most
of the input you get from these parts is pretty good (and Grunff is one
of the good guys!)

When I get to know everything about everything as you clearly do I will be
able to advise accordingly and not delight in smug and arrogant answers.

Not read much IMM yet then ;-)



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:

That is actually straight forward, and would be handled by a decent
constant current delta peek charger.

The voltage is not actually relevant since a constant current supply
will modulate this so as to achieve the selected current (i.e. charge
rate). Monitoring the applied voltage should show a slight rise with
time, with a peek and then a decline as the pack reaches full charge.
The delta peek detector will sense this and turn off (or reduce) the
charge current at that time.


That easy, eh? ;-)

But it would need to be able to apply a voltage high enough to drive the
necessary current, right? So if a charger is built with the intention of
charging say 12V packs max, it may not be capable of applying a high
enough voltage to push any current through a 24V pack, no?


--
Grunff

In article ,
Grunff wrote:
That is actually straight forward, and would be handled by a decent
constant current delta peek charger.

The voltage is not actually relevant since a constant current supply
will modulate this so as to achieve the selected current (i.e. charge
rate). Monitoring the applied voltage should show a slight rise with
time, with a peek and then a decline as the pack reaches full charge.
The delta peek detector will sense this and turn off (or reduce) the
charge current at that time.


That easy, eh? ;-)

But it would need to be able to apply a voltage high enough to drive the
necessary current, right? So if a charger is built with the intention of
charging say 12V packs max, it may not be capable of applying a high
enough voltage to push any current through a 24V pack, no?

As a theoretical point, you could make a charger to cope with the majority
of common power tool batteries, yes. But of course cost is a factor, so
this isn't likely with commercial designs from B&Q.

IMHO ;-) I charge all these at the 14 hour rate - and they thank me for
it. ;-)

--
*Am I ambivalent? Well, yes and no.

Dave Plowman London SW
To e-mail, change noise into sound.

fred wrote:

Google groups by author is usually a laugh on suspect posters and yup
9/10 gasp posts really are genuine . . . . , v scary.

A good one from markb, "Brass is metal, I suspect you mean steel"

John Rumm wrote:

That is actually straight forward, and would be handled by a decent
constant current delta peek charger.

So why has my "decent" Ansmann delta V charger got a NiMH/NiCd switch?

It does detect dead batteries (NiMH and NiCd) and those inserted with
incorrect polarity ...

Andy Burns wrote:


So why has my "decent" Ansmann delta V charger got a NiMH/NiCd switch?

AFAIR, because (a) the delta-V is much more pronounced for NiCd than
NiMH, so telling the charger what you've got avoids oversensitive
premature switching to trickle-mode for NiCd; (b) because trickle/top-up
charging for NiMH wants to be at a notably lower current (C/50?) than
for NiCd (C/15?), so telling the charger what you've got avoids
overcooking the NiMH cells.

The 'nicest' chargers supplement delta-V detection with temperature-rise
detection; but that's hard to do reliably without a dedicated thermistor
deep in the heart of the pack - common enough on higher-end batteries,
but no standard contact arrangement means 'universal' chargers don't do
it, and it's awkward to arrange for a thermistor to be in good enough
contact with generic single cells to be much use.

At least, that's what my long-ago reading of Maxim charge-control-IC
datasheets has left in my brain ;-)

Stefek

Stefek Zaba wrote:

[snip]

telling the charger what you've got avoids
overcooking the NiMH cells.

Indeed, using a bit of delta-T as well (but that would be difficult on
mine as it has a fan to cool the batteries down) sorry it was a
rhetorical question.

Just wondering how John's mythical universal charger would know!

At least, that's what my long-ago reading of Maxim charge-control-IC
datasheets has left in my brain ;-)

The newer ones also have a non-volatile memory and a built in ammeter to
integrate the total charge ...

Grunff wrote:

That easy, eh? ;-)

You can get the clever stuff all bundled into single ICs these days...
so no need to be more complex than a PSU (if you ignore the minor point
of the black magic that goes on inside some SMPS!)

But it would need to be able to apply a voltage high enough to drive the
necessary current, right? So if a charger is built with the intention of
charging say 12V packs max, it may not be capable of applying a high
enough voltage to push any current through a 24V pack, no?

Yup spot on. For any given design of charger there will be a maximum
number of cells that it can cope with. Oddly more is not difficult (just
use a higher voltage output transformer, but then doing fewer cells
becomes harder since you have more volts to drop across your regulator.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Dave Plowman (News) wrote:

As a theoretical point, you could make a charger to cope with the majority
of common power tool batteries, yes. But of course cost is a factor, so
this isn't likely with commercial designs from B&Q.

If you think about it there is a market opportunity here. Stick a
"standard" socket on all battery packs in addition to the normal
connector used by the tool to allow connection of a third party charger.
Then offer a "cheaper still" range of tools that come without a charger
for those who have already bought a "one size fits all" charger.

The flaw in that suggestion however is that most of these sophisticated
charging schemes work so much better on packs where the cells are
reasonably matched, which rules out your average shed special (or at
least condemns the pack to a short life irrespective of the care of the
charger)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Andy Burns wrote:

Just wondering how John's mythical universal charger would know!

You could stick a switch on the side for NiMH/NiCd ;-)

(not looked at charging ICs lately, but I wonder if there is a way of
actually detecting the cell type electrically from the outset)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Stefek Zaba wrote:

The 'nicest' chargers supplement delta-V detection with temperature-rise
detection; but that's hard to do reliably without a dedicated thermistor
deep in the heart of the pack - common enough on higher-end batteries,

Like my 'higher end' Ferm combi for example! :-)

--
Chris Green

Grunff wrote:

John Rumm wrote:

That is actually straight forward, and would be handled by a decent
constant current delta peek charger.

The voltage is not actually relevant since a constant current supply
will modulate this so as to achieve the selected current (i.e. charge
rate). Monitoring the applied voltage should show a slight rise with
time, with a peek and then a decline as the pack reaches full charge.
The delta peek detector will sense this and turn off (or reduce) the
charge current at that time.



That easy, eh? ;-)

But it would need to be able to apply a voltage high enough to drive the
necessary current, right? So if a charger is built with the intention of
charging say 12V packs max, it may not be capable of applying a high
enough voltage to push any current through a 24V pack, no?


Correct.

Most delta peak chargers use switched mode regulators that
automatically adjust the voltage to whaveter is necessary to get te
charge curent.

Andy Burns wrote:

John Rumm wrote:

That is actually straight forward, and would be handled by a decent
constant current delta peek charger.


So why has my "decent" Ansmann delta V charger got a NiMH/NiCd switch?

The delta peak on NiMh is less than 2mV, but its about 3-5mV on NiCd.

IIRC.

The NiCd setting is eneeded to fully charge the NiCd which oterwise
would terminate a bit early.



It does detect dead batteries (NiMH and NiCd) and those inserted with
incorrect polarity ...

Easy once you have a feedback and computer system to drive it...

Dave Plowman (News) wrote:

In article ,
Grunff wrote:

That is actually straight forward, and would be handled by a decent
constant current delta peek charger.

The voltage is not actually relevant since a constant current supply
will modulate this so as to achieve the selected current (i.e. charge
rate). Monitoring the applied voltage should show a slight rise with
time, with a peek and then a decline as the pack reaches full charge.
The delta peek detector will sense this and turn off (or reduce) the
charge current at that time.



That easy, eh? ;-)


But it would need to be able to apply a voltage high enough to drive the
necessary current, right? So if a charger is built with the intention of
charging say 12V packs max, it may not be capable of applying a high
enough voltage to push any current through a 24V pack, no?


As a theoretical point, you could make a charger to cope with the majority
of common power tool batteries, yes. But of course cost is a factor, so
this isn't likely with commercial designs from B&Q.

IMHO ;-) I charge all these at the 14 hour rate - and they thank me for
it. ;-)

Such cahrgers are avaialable at any model shop where e.g. electic racing
cars or aircraft are sold.

Price typically 30-50 quid for and up to 14 cell, fully regulated
NiMh/Nicd etc etc design. Chrage currents up to 6-8A usually.

Mostly they are designed to run off 12v sources though.

John Rumm wrote:

You could stick a switch on the side for NiMH/NiCd ;-)

At least that way when it burns up your batteries you can blame the
user, not the design of the charger!

I remember seeing a photo somewhere of a rapid charger that was melted
and not far short of catching fire, it had the remnants of NiMH
batteries in it, but the switch was set to NiCd (or vice-versa) can't
find it again to post a link :-(

mark b wrote:
I've got loads of them. I'm sure I'm not alone. The thing is I no longer
know which adaptor came with what tool.

You're not alone; although I'm very careful about physically labelling
every new wallwart as it comes through the door, to avoid muddling them
later, I do have a boxful of the damned things in the garage, belonging
to sundry expired electrical devices - mostly mains adapters but some
chargers.

Unfortunately, I haven't a clue which I could safely use on other
equipment, so I don't. I (and certainly my kids) have multiple
battery-operated devices around the home, fitted with sockets for a
mains-adapter which I don't have. I look wistfully at my box of old
wallwarts before deciding I can't risk it, and so go out and buy another
pallet-load of Duracells or... yet another wallwart.

Is there anyway of working out where it would be safe to use old wall
warts? Reading the other posts in this thread hasn't helped my
confusion on the issue.

For example, my 'intelligent' battery charger (which takes 4x1.2V NiMH
cells) has a wallwart rated 3V @ 2.5A. The charger for my son's RC car
(6x1.2V NiCd cells) is rated 9V @ 200mA. The mains adapter for my
cordless doorbell (which is otherwise powered by 4x1.2V cells) is 9V @
300mA.

Don't get it!

David

Lobster wrote:

Is there anyway of working out where it would be safe to use old wall
warts? Reading the other posts in this thread hasn't helped my
confusion on the issue.

The appliance will often be labeled with at least the voltage and the
polarity required by its power connector. Hence matching on that basis
is a good start. There are two other issues, can the wall wart meet the
power requirements, and does the appliance require a regulated supply
(most don't)

The power usage is easy enough to test, guestimate the power
requirements and select a wall wart from your box with the right voltage
and "enough" power. Hook it up but via a DMM set to read mA (a butchered
lead from another wall wart will help here, because the DMM will need to
be in series with the supply). Switch on, and monitor the current draw
for a bit. If the current draw is way over the rating of the wall wart
you can disconnect sharpish (assuming it doesn't do it for you ;-), if
it is way under the wall warts capability, select a similar but lower
power one from the box, and keep the bigger one for something that needs
it.

For example, my 'intelligent' battery charger (which takes 4x1.2V NiMH
cells) has a wallwart rated 3V @ 2.5A. The charger for my son's RC car
(6x1.2V NiCd cells) is rated 9V @ 200mA. The mains adapter for my
cordless doorbell (which is otherwise powered by 4x1.2V cells) is 9V @
300mA.

Don't get it!

Don't forget some devices will have built in voltage regulators, and
hence may have supplies with a voltage somewhat higher than the battery
voltage. Some devices will work over a big range of supply voltages, and
hence can use a lower voltage supply than the sum of the batteries in
the same way they will work from partially exhausted cells.

Your battery charger in the above example may be a slightly different
type of beastie... it is possible that it charges cells individually
rather than all in series (does it charge one or two at a time, rather
than needing 4 cells?). If this is the case then 3V is plenty to charge
a single 1.2V cell.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
Lobster wrote:

Is there anyway of working out where it would be safe to use old
wall
warts? Reading the other posts in this thread hasn't helped my
confusion on the issue.

The appliance will often be labeled with at least the voltage and the

polarity required by its power connector. Hence matching on that
basis
is a good start. There are two other issues, can the wall wart meet
the
power requirements, and does the appliance require a regulated supply

(most don't)

The power usage is easy enough to test, guestimate the power
requirements and select a wall wart from your box with the right
voltage
and "enough" power. Hook it up but via a DMM set to read mA (a
butchered

CHECK THE POLARITY FIRST!!!

The commonly used DC connectors can have the positive either in the
centre or on the outer conductor.
Also, is the wall wart AC or DC? What does the equipment expect?

MBQ

wrote:

CHECK THE POLARITY FIRST!!!

I thought I said that... no need to shout.

The commonly used DC connectors can have the positive either in the
centre or on the outer conductor.

Errrm, yup you could be right.... or are some the other way round?

Also, is the wall wart AC or DC? What does the equipment expect?

With one or two rare exceptions (modems, low voltage lights etc), DC.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
wrote:

CHECK THE POLARITY FIRST!!!

I thought I said that... no need to shout.

Sorry, you did.


The commonly used DC connectors can have the positive either in the
centre or on the outer conductor.

Errrm, yup you could be right.... or are some the other way round?

At the risk of sounding like IMM, I am right:-). I have one of each on
my desk at the moment.


Also, is the wall wart AC or DC? What does the equipment expect?

With one or two rare exceptions (modems, low voltage lights etc), DC.

Every PC in our office has speakers that have an AC wall wart. I don't
think they're all that rare.

MBQ

wrote:

The commonly used DC connectors can have the positive either in the
centre or on the outer conductor.

Errrm, yup you could be right.... or are some the other way round?


At the risk of sounding like IMM, I am right:-). I have one of each on
my desk at the moment.

Perhaps you missed the irony of what I was saying... ;-)

You said "The commonly used DC connectors can have the positive either
in the centre or on the outer conductor", which does kind of wrap up all
of the available posibilities don't you think? Hence why I said you
could be (i.e. must be!) right given that it will be one way or the other.

Every PC in our office has speakers that have an AC wall wart. I don't
think they're all that rare.

To be fair, that is still a sample of one (i.e. one type of speaker
presumably)... I would maintaing that ones with AC outputs are
outnumbered at least 10:1 by DC ones in general use.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:


To be fair, that is still a sample of one (i.e. one type of speaker
presumably)... I would maintaing that ones with AC outputs are
outnumbered at least 10:1 by DC ones in general use.


Certainly consistent with my collection of wallwarts: the great bulk of
'em are DC, just about the only AC ones were for modems which for some
reason (an addiction to 50Hz as a source of timing? but then it's 60 in
some benighted parts of the world) seemed to be about 50:50 in
preferring ACC.

Of course, some - as the Scarecrow said - go both ways...

In article ,
Stefek Zaba wrote:
Certainly consistent with my collection of wallwarts: the great bulk of
'em are DC, just about the only AC ones were for modems which for some
reason (an addiction to 50Hz as a source of timing? but then it's 60 in
some benighted parts of the world) seemed to be about 50:50 in
preferring ACC.

Technically, it's a better solution to have the wall wart as AC only and
the rest of the PS in the appliance - you get a lower impedance supply
that way, with less chance of RFI in either direction. Also allows a
bigger transformer - ie more current - in the limited space.

I wonder in the case of modems whether it's also to do with minimising the
risk of putting anything nasty down the telephone line - but that's only
surmising.

--
*Re-elect nobody

Dave Plowman London SW
To e-mail, change noise into sound.

Huge wrote:


Good news; I have a boxfull of wall-warts which I could look through
and gather some data.

Bad news; ICBA.

Good news: Humph's put his tongue across the one marked '9V DC'.

Bad news: it was adequately isolated from line.

Good news: it *was* adequately isolated from line, but then...



And now, late arrivals at the Part P ball.

Here's Mr & Mrs Icy, and their pleasant son, Nice.

Here's the Iranian couple, Mr & Mrs Al Oda Coblaz, and their peasant
revolutionary son, Wat.

Here are Mr & Mrs Works - and their younger son, Minor.

And is that - yes it is, Mr & Mrs Pection, and their son Richard dressed
as, well, some sort of a mixture of clown and Victorian novelist - yes,
it's Pierot Dickens!

Stefek Zaba wrote:

Good news: Humph's put his tongue across the one marked '9V DC'.

That reminds me... phone call a good few years ago from girl who would
later become my SiL.

SiL: "My Saga GameGear is not working"
Me: "Perhaps the batteries are flat"
SiL: "I have not got any spare batteries, so I am using the mains adapter"
Me: "Is that working?"
SiL: "I don't know... how can I tell?"

Me: ponders, how to remotely diagnose function of a wall wart with no
test gear, and a non techie proxy...

Me: "Just touch the jack plug on your tongue, if it is working you
should get a little tingle..."
SiL: "Is it safe?"
Me: "Yup, you will be fine, it is only 9V"

Pause...

SiL: "Yooowwwwwwwwww! that hurt"
Me, and future SWMBO in unison (4 feet away from phone): "OK that's
working then!"

Ponders... Hmm it was an unregulated supply, so with no load it probably
had 16V on it.... ;-))

And is that - yes it is, Mr & Mrs Pection, and their son Richard dressed
as, well, some sort of a mixture of clown and Victorian novelist - yes,
it's Pierot Dickens!

Argggg... now that was bad, now please go test one of your spare wall
warts using the above test procedure....

Oh a late arrival: Mr & Mrs Bel-plyance, and their lovely, but alas
excluded daughter, Porta.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:


Me: "Just touch the jack plug on your tongue, if it is working you
should get a little tingle..."


I felt the passing of the illusion of teenage invulnerability keenly
some years ago, when wondering whether to put my tongue across the PP3
powering the RS232 tester I wasn't sure was working; I'd often tested
PP3s this way in my youth and fancy I can still tell the difference
between fresh and aged. The realisation that this was a NiCd, with a
somewhat lower internal resistance than the zinc-chloride batteries of
my youth (hear that Hovis advert ;-) came while the terminals were still
a couple of feet away ;-)

In article ,
Stefek Zaba wrote:
I felt the passing of the illusion of teenage invulnerability keenly
some years ago, when wondering whether to put my tongue across the PP3
powering the RS232 tester I wasn't sure was working; I'd often tested
PP3s this way in my youth and fancy I can still tell the difference
between fresh and aged. The realisation that this was a NiCd, with a
somewhat lower internal resistance than the zinc-chloride batteries of
my youth (hear that Hovis advert ;-) came while the terminals were still
a couple of feet away ;-)

Thought the resistance of a half inch or so of tongue would have made the
internal resistance of the source irrelevant? Unless of course you'd been
eating something strange?

Many of my colleagues test radio mic PP3s like this.
I just replace them. ;-)

--
*I'm really easy to get along with once people learn to worship me

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:

Thought the resistance of a half inch or so of tongue would have made the
internal resistance of the source irrelevant? Unless of course you'd been
eating something strange?

I 'spect you're right about that - but the evolving caution made me
reluctant to try it.

Besides, what resistance? They don't call me 'silvertongue' for nothing ;-)

"Dave Plowman (News)" wrote in message
...
In article ,
Stefek Zaba wrote:
I felt the passing of the illusion of teenage invulnerability keenly
some years ago, when wondering whether to put my tongue across the PP3
powering the RS232 tester I wasn't sure was working; I'd often tested
PP3s this way in my youth and fancy I can still tell the difference
between fresh and aged. The realisation that this was a NiCd, with a
somewhat lower internal resistance than the zinc-chloride batteries of
my youth (hear that Hovis advert ;-) came while the terminals were still
a couple of feet away ;-)

Thought the resistance of a half inch or so of tongue would have made the
internal resistance of the source irrelevant? Unless of course you'd been
eating something strange?

Many of my colleagues test radio mic PP3s like this.
I just replace them. ;-)


We were well used to doing this with batteries when children, for fun (you
had to make your own amusement back then). One of my mates decided to try it
with the output of the 12V transformer we used to run my Triang train set
(TT gauge for the anoraks). When he was able to describe the experience,
some minutes later, he said it was akin to being hit by two torpedoes,
simultaneously, one on each temple. I was disinclined to try it.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)