So Christmas has come and gone, bringing with it the usual influx of new
low-voltage power supplies for assorted gadgets and gizmos.
Unbelievable. When are these things going to get at least half-way
standardised to avoid having to have so many lying around?

Anyway...

One new incoming gadget was an LG mobile phone. As it happens, we
already have an LG charger in the house from another (now stolen) model:
they look physically identical and have the same proprietary jackplugs.

The old wallwart says it puts out 4.8V / 0.9A; but the new one is 5.1V /
0.7A (ie higher volts but lower current).

Can we use the old charger on the new phone without worry, or should I
bin it urgently to avoid an 'accident'?

Thanks
David

Lobster wrote:

So Christmas has come and gone, bringing with it the usual influx of new
low-voltage power supplies for assorted gadgets and gizmos.
Unbelievable. When are these things going to get at least half-way
standardised to avoid having to have so many lying around?

Anyway...

One new incoming gadget was an LG mobile phone. As it happens, we
already have an LG charger in the house from another (now stolen) model:
they look physically identical and have the same proprietary jackplugs.

The old wallwart says it puts out 4.8V / 0.9A; but the new one is 5.1V /
0.7A (ie higher volts but lower current).

Can we use the old charger on the new phone without worry, or should I
bin it urgently to avoid an 'accident'?

Thanks
David

Hard to imagine any possible situation in which that could cause a
problem.


NT

On Fri, 26 Dec 2008 14:44:11 +0000, Lobster
wrote:


One new incoming gadget was an LG mobile phone. As it happens, we
already have an LG charger in the house from another (now stolen) model:
they look physically identical and have the same proprietary jackplugs.

The old wallwart says it puts out 4.8V / 0.9A; but the new one is 5.1V /
0.7A (ie higher volts but lower current).


My suspicion would be that neither are as accurate as stated - but can you put a
meter probes into the connector of the old one (off load) to check if it really
is 4.8v?
The lower (if it is) voltage should not cause any damage and the current
available is slightly more than required but again no damage likely.

If the unloaded output voltages are exactly as stated then it is /just/ possible
that battery would not charge fully - but my bet is that there would be no
difference.
Try a google for the phone model number (and charger) to see what amazon/ebay
etc offer as replacement chargers for that model.

Geo

"Geo" wrote in message
...
On Fri, 26 Dec 2008 14:44:11 +0000, Lobster

wrote:


One new incoming gadget was an LG mobile phone. As it happens, we
already have an LG charger in the house from another (now stolen) model:
they look physically identical and have the same proprietary jackplugs.

The old wallwart says it puts out 4.8V / 0.9A; but the new one is 5.1V /
0.7A (ie higher volts but lower current).


My suspicion would be that neither are as accurate as stated - but can you
put a
meter probes into the connector of the old one (off load) to check if it
really
is 4.8v?
The lower (if it is) voltage should not cause any damage and the current
available is slightly more than required but again no damage likely.

If the unloaded output voltages are exactly as stated then it is /just/
possible
that battery would not charge fully - but my bet is that there would be no
difference.
Try a google for the phone model number (and charger) to see what
amazon/ebay
etc offer as replacement chargers for that model.

Geo

All so wasteful of resources.

Campaigners get on their hobby-horse about issues like leaving things
plugged in but fail to address the production of items that are not needed.

My pet hate is crap batteries. Little use - shipped from China and end up
polluting our land.

On Fri, 26 Dec 2008 14:44:11 +0000, Lobster wrote:

When are these things going to get at least half-way standardised to
avoid having to have so many lying around?

USB (nominal 5v up to 500mA) is slowly creeping in as a defacto standard
on many things but frequently without the smarts that really should be
there for proper negotiation to get 500mA. How kit behaves when connected
to something that doesn't current limit to 100mA without negotiation seems
to be a little variable.

--
Cheers
Dave.

On 26 Dec, 20:12, "Dave Liquorice"
wrote:

USB (nominal 5v up to 500mA) is slowly creeping in as a defacto standard
on many things but frequently without the smarts that really should be
there for proper negotiation to get 500mA.

There's a (tiny) chipset for that.

I recently saw heated gloves with USB power connectors. Seems that off-
road cyclists are taking to these things as a simple power connector
for a few watts of lighting or heating.

In article et,
"Dave Liquorice" writes:
On Fri, 26 Dec 2008 14:44:11 +0000, Lobster wrote:

When are these things going to get at least half-way standardised to
avoid having to have so many lying around?

USB (nominal 5v up to 500mA) is slowly creeping in as a defacto standard
on many things but frequently without the smarts that really should be
there for proper negotiation to get 500mA. How kit behaves when connected
to something that doesn't current limit to 100mA without negotiation seems
to be a little variable.

I've never yet seen a USB port which actually polices
the current draw against what's been negotiated.

However, some phones detect the difference between about 5V
and 5.5V in order to detect if they're plugged into a real
USB port (5V) in which case they limit their current draw
to low levels, or mains adaptor (5.5V) in which case they'll
do things like fast charging at much higher current draw.

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

Andrew Gabriel presented the following explanation :
However, some phones detect the difference between about 5V
and 5.5V in order to detect if they're plugged into a real
USB port (5V) in which case they limit their current draw
to low levels, or mains adaptor (5.5V) in which case they'll
do things like fast charging at much higher current draw.

Certain (maybe all) Nokia phones can be used with a Nokia sourced
charger which come in two versions - the standard one and the fast
charger. There is no marked difference in the output voltage on the
chargers, so I did wonder how the phone might detect which type of
charger it was plugged into. I guess the voltages must be different
despite the markings.

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

Geo wrote:
On Fri, 26 Dec 2008 14:44:11 +0000, Lobster
wrote:


One new incoming gadget was an LG mobile phone. As it happens, we
already have an LG charger in the house from another (now stolen) model:
they look physically identical and have the same proprietary jackplugs.

The old wallwart says it puts out 4.8V / 0.9A; but the new one is 5.1V /
0.7A (ie higher volts but lower current).


My suspicion would be that neither are as accurate as stated - but can you put a
meter probes into the connector of the old one (off load) to check if it really
is 4.8v?

Not readily - the LG connector is a weird, flat multi-pin job with
recessed connectors very close together!

Try a google for the phone model number (and charger) to see what amazon/ebay
etc offer as replacement chargers for that model.

Well, AFAICS they seem to sell a generic charger for both phones;
however I'm not sure whether that means anything or not.

FWIW the phones/chargers are as follows:
LG Chocolate: STA-P51US charger, 4.8V / 0.9A
LG Viewty: STA-P52UR charger, 5.1V / 0.7A

Thanks
David

On Sat, 27 Dec 2008 11:51:00 +0000, Lobster
wrote:

STA-P51US

Well Orange say it is compatible with both phones...
http://www.orangeaccessories.co.uk/s...l_charger.html

Geo

Andrew Gabriel wrote:

I've never yet seen a USB port which actually polices
the current draw against what's been negotiated.

I've encountered laptops that do, but not recently. I suspect that the
abundance of cheap "USB"-powered devices that don't ask nicely for power
means that all modern hosts will supply the full 500mA regardless,
otherwise they (rather than the out-of-spec device) are perceived as not
working properly.

Pete