I bought a couple of wind-up dynamo LED lanterns in anticipation of the
winter power cuts. They have a 6volt charging socket but there is no
indication of the polarity on the case next to the socket and no
instructions as to polarity. My understanding is that the usual convention
is that the central pin is positive and the outer sleeve is negative on the
charging plug. Is this likely to be correct?

An adaptor was not included but I have got a regulated DC adaptor that can
be set from 1.5 to 12volts with either a positive or negative tip.

DIY explained :
I bought a couple of wind-up dynamo LED lanterns in anticipation of the
winter power cuts. They have a 6volt charging socket but there is no
indication of the polarity on the case next to the socket and no instructions
as to polarity. My understanding is that the usual convention is that the
central pin is positive and the outer sleeve is negative on the charging
plug. Is this likely to be correct?

There is no convention, but more often than not tip is positive.


An adaptor was not included but I have got a regulated DC adaptor that can be
set from 1.5 to 12volts with either a positive or negative tip.

The only way to be certain is to disassemble and check. If the battery
is connected directly across the socket it might be possible to plug a
plug into it and check its polarity with a meter, but likely there will
be a diode in series to prevent wrong polarity, especially so if it is
unmarked.

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

In article ,
"DIY" writes:
I bought a couple of wind-up dynamo LED lanterns in anticipation of the
winter power cuts. They have a 6volt charging socket but there is no
indication of the polarity on the case next to the socket and no
instructions as to polarity. My understanding is that the usual convention
is that the central pin is positive and the outer sleeve is negative on the
charging plug. Is this likely to be correct?

An adaptor was not included but I have got a regulated DC adaptor that can
be set from 1.5 to 12volts with either a positive or negative tip.

+ve centre is most common, but not universal.
You might find that you can measure a polarity on the socket
with a test meter, but it might not handle being shorted out
without damage.

Another issue is if the socket is meant for a power supply
or a charger, and this will depend if the unit contains its
own charging circuit.

Without any details being provided, you are probably going
to have to open it up to be sure what's inside, and if it
needs a charger, what type and capacity battery it has.

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

On Sat, 22 Aug 2009 12:33:58 +0100, Harry Bloomfield
wrote:

The only way to be certain is to disassemble and check. If the battery
is connected directly across the socket it might be possible to plug a
plug into it and check its polarity with a meter, but likely there will
be a diode in series to prevent wrong polarity, especially so if it is
unmarked.

You'd think so, wouldn't you? Especially on something expensive like
a Sony Walkman Pro? But there isn't. Big repair bill if you get it
wrong :-(

On Aug 22, 12:35*pm, (Andrew Gabriel)
wrote:
In article ,
* * * * "DIY" writes:

I bought a couple of wind-up dynamo LED lanterns in anticipation of the
winter power cuts. They have a 6volt charging socket but there is no
indication of the polarity on the case next to the socket and no
instructions as to polarity. My understanding is that the usual convention
is that the central pin is positive and the outer sleeve is negative on the
charging plug. Is this likely to be correct?

An adaptor was not included but I have got a regulated DC adaptor that can
be set from 1.5 to 12volts with either a positive or negative tip.

+ve centre is most common, but not universal.
You might find that you can measure a polarity on the socket
with a test meter, but it might not handle being shorted out
without damage.

Another issue is if the socket is meant for a power supply
or a charger, and this will depend if the unit contains its
own charging circuit.

Without any details being provided, you are probably going
to have to open it up to be sure what's inside, and if it
needs a charger, what type and capacity battery it has.

I think thats the only way forward really, to open it and find out
whats there. Good chance of killing it otherwise.


NT

In article ,
Laurence Payne wrote:
On Sat, 22 Aug 2009 12:33:58 +0100, Harry Bloomfield
wrote:

The only way to be certain is to disassemble and check. If the battery
is connected directly across the socket it might be possible to plug a
plug into it and check its polarity with a meter, but likely there will
be a diode in series to prevent wrong polarity, especially so if it is
unmarked.

You'd think so, wouldn't you? Especially on something expensive like
a Sony Walkman Pro? But there isn't. Big repair bill if you get it
wrong :-(

They're punishing you for not using their PS, etc. ;-)

--
*Your kid may be an honours student, but you're still an idiot.

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

"DIY" wrote in message ...
I bought a couple of wind-up dynamo LED lanterns in anticipation of the
winter power cuts. They have a 6volt charging socket but there is no
indication of the polarity on the case next to the socket and no
instructions as to polarity. My understanding is that the usual convention
is that the central pin is positive and the outer sleeve is negative on
the
charging plug. Is this likely to be correct?

An adaptor was not included but I have got a regulated DC adaptor that can
be set from 1.5 to 12volts with either a positive or negative tip.


Place a test meter on the socket. The battery is connected to the socket,
so a test meter will show you which way round it is connected to the socket.

Like this
http://www.diy.com/diy/jsp/bq/nav.js...&isSearch=true
.
...

"BigWallop" wrote:
Place a test meter on the socket. The battery is connected to the socket,
so a test meter will show you which way round it is connected to the
socket.

Thanks for that tip, I tried it and the meter showed that the tip/centre pin
is positive.

On Aug 22, 3:18*pm, "DIY" wrote:
"BigWallop" wrote:
Place a test meter on the socket. *The battery is connected to the socket,
so a test meter will show you which way round it is connected to the
socket.

Thanks for that tip, I tried it and the meter showed that the tip/centre pin
is positive.

If the battery connects straight to the socket you'll need a suitable
charger, not a gen purp wallwart.


NT

"NT" wrote:
If the battery connects straight to the socket you'll need a suitable
charger, not a gen purp wallwart.

As stated in my original post I have got a regulated DC adaptor that can be
set from 1.5 to 12volts with either a positive or negative tip, and which I
have since used to charge both lanterns at 6volts. What is a wallwart?

On Sat, 22 Aug 2009 21:49:14 +0100, "DIY" wrote:

If the battery connects straight to the socket you'll need a suitable
charger, not a gen purp wallwart.

As stated in my original post I have got a regulated DC adaptor that can be
set from 1.5 to 12volts with either a positive or negative tip, and which I
have since used to charge both lanterns at 6volts. What is a wallwart?

What you're describing, if it looks like a pregnant 13-amp plug :-)

If there's no charging control circuitry in the appliance you'll just
have to make sure you don't leave it connected too long. A proper
charging system would be kinder to the batteries. But I wouldn't
worry too much. It's only a gadget, not the backup power supply to a
life-support system.

On Aug 22, 9:49*pm, "DIY" wrote:
"NT" wrote:

If the battery connects straight to the socket you'll need a suitable
charger, not a gen purp wallwart.

As stated in my original post I have got a regulated DC adaptor that can be
set from 1.5 to 12volts with either a positive or negative tip, and which I
have since used to charge both lanterns at 6volts. What is a wallwart?

Thats one way to knacker it.


NT

In article ,
Laurence Payne writes:
On Sat, 22 Aug 2009 21:49:14 +0100, "DIY" wrote:

If the battery connects straight to the socket you'll need a suitable
charger, not a gen purp wallwart.

As stated in my original post I have got a regulated DC adaptor that can be
set from 1.5 to 12volts with either a positive or negative tip, and which I
have since used to charge both lanterns at 6volts. What is a wallwart?

What you're describing, if it looks like a pregnant 13-amp plug :-)

If there's no charging control circuitry in the appliance you'll just
have to make sure you don't leave it connected too long. A proper
charging system would be kinder to the batteries. But I wouldn't
worry too much. It's only a gadget, not the backup power supply to a
life-support system.

I guess it didn't have Lithium batteries (wrong voltage anyway),
or he'd be describing the resulting indoor firework display ;-)

(Having just knocked up something on the workbench to charge up
my Nokia phone's Lithium battery as the phone no longer can,
that's fresh on my mind. Fortunately, it worked very well.)

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