Mobile Phone Chargers - Expensive to Run ?

[Mike Meakin]

Southern Electric (UK Energy supplier) have sent me a leaflet urging me to
use less of their product (electricity).

In it they state:

"Unplug your mobile phone charger - these little black boxes suck 100kWhrs
(sic) from your socket, even when the phone is fully charged"

Am I correct in thinking that is one hundred, thousand Watts per hour ? I
didn't think it was quite that much but perhaps might explain why my
electricity bills are so high ?

If a 'unit' of their electricity (1000 Watts for one hour) costs about 10
pence, then each day I am paying 24 x 100,000 x 10p = £240,000 per day. Wow
!

Am I missing something here ?

 

[Homer J Simpson]

"Unplug your mobile phone charger - these little black boxes suck 100kWhrs
(sic) from your socket, even when the phone is fully charged"

Only if you count world wide. And you get all of the power as heat which is
nice right now.

 

[Pete Wilcox]

Southern Electric (UK Energy supplier) have sent me a leaflet urging me to
use less of their product (electricity).

In it they state:

"Unplug your mobile phone charger - these little black boxes suck 100kWhrs
(sic) from your socket, even when the phone is fully charged"

Am I correct in thinking that is one hundred, thousand Watts per hour ? I
didn't think it was quite that much but perhaps might explain why my
electricity bills are so high ?

If a 'unit' of their electricity (1000 Watts for one hour) costs about 10
pence, then each day I am paying 24 x 100,000 x 10p = £240,000 per day. Wow
!

Am I missing something here ?

Hee hee hee. I think your initial mistake is confusing the meaning of
"100kW-hrs". Not 100 kW *PER* hour, but more likely 100 kW-hrs in
total over the expected lifespan of the charger. (=100 x 10p = 10
pounds.) You'd need to have quite a few kettles continually on the boil
to achieve a figure of 100 kW per hour.

But one thing's for sure - these damn wall-warts do continue to suck power
from the mains, even while they're not doing anything useful - like
recharging spent batteries - so the advice is sensible; always unplug
the buggers when they're not actualy being used. As overheating
wall-warts are an increasingly common cause of house fires, it makes sense
from a safety point of view too.

Cheers,
Pete.

 

[Mike Meakin]

Thank you all for your replies.

That makes much more sense. I just quoted what was in the leaflet and
thought that I had misunderstood the meaning of the units.

So perhaps 100mW per hour (max) rather than 100kW per hour, so out by a
factor of a million ?

Or perhaps 100kW per hour for all the UK phone chargers (say a million)

 

[Zak]

The information you have is not accurate. Mobile phone chargers are very
efficient. They pull about 10 to about 30 mw (milliwatts) when at idle.

Many of the older iron-core transformer ones get noticeably warm, even
when not charging anything. These will use around a watt I suppose. A
watt * a year = 8 KWh, which would come around 80 p or a bit above a
euro - depending on cost and taxation.

The Netherlands has an energy tax that nearly doubles the cost of
electricity, but also gives back 190 euro to pay this tax from. On my
bill the energy tax is a net win, though my incremental energy costs are
higher than they would be without tax. Which makes saving make sense.

If you read the electrical specification on the label on the charger unit,
it should indicate the maximum possible current it can pull in the worse
case possible.

My charger says 20 mA, x 230 volts = 2.6 watts. But this is inductive,
and won't be the real power.

In any case, the modern electronic lightweight switcher chargers use
very little power when idle. My laptop power brick claims less than half
a watt, and that is a 65 watt output brick.


Thomas