Charger electricity use.

[RichardCoulter]

A few years ago, I was told that it was better for the environment (and the bill) for people to switch off the socket that the charger is plugged into, rather than just leaving it when the phone is unplugged for the next time. It was said that this was because the same power is used whether the phone is plugged in & charging or not.

However, I was told yesterday that newer technology means that a lot less power is used/wasted in the same situation these days, so it's not worth bothering any more.

Does anybody know if this is true?

I use a cheap (non Smart) VM phone, I don't know if Smartphones use any more power.

Many thanks.

[techguyone]

My understanding was these things only draw power when charging, They aren't high drain in any case, I think it's literally pennies to charge a device & if it's not actually connected to a device, I wouldn't have thought its using anything (unless it has a LED light) even that is a tiny tiny draw.

[Kymmy]

Linear transformers (old style) are inefficient (due to the way that the regulator circuit dumps the excess voltage) even when there's no current draw so yes there was loss but not really a great deal unless you're talking about 60-100 amp 12v PSU's that I regularly use (mainly for radio applications due to less interference)

Switch mode (new style) has actually been around for 40 years and 99.99999999% of PC's ever produced have used one. They are more efficient as they can turn off the circuit when no draw is detected by using an even smaller sub circuit. It's likely that for the last 20 years you've been using this type of PSU to charge your phone, run a laptop so not really newer tech.

[heero_yuy]

I design these switching PSU's for a living and can conform that off load they draw next to nothing. Maybe 0.1W

Power = heat so if it stays cold...

[RichardCoulter]

Thanks everybody for the information.

This article says that leaving the charger plugged in uses a matter of pennies a year, but that the real waste is people leaving their devices plugged in after the device has fully charged- this wastes enough energy to heat a bath every year.

I, and I suspect many others, tend to plug in the phone before bed until the following morning. It looks like it would save more energy by doing it for an hour or two before bed.

However, do devices stop drawing power when the device is fully charged and trigger the 'switch mode' that Kymmy mentioned? If so, the article is misleading.

http://www.techradar.com/news/phone-...night--1280918

[techguyone]

My understanding was with modern phones and so on, they're smart enough to only draw when they need to.

[Stephen]

I don't think its a waste as most devices once up to 100% stop charging so the battery drops a bit then tops up the battery continuously. Trickle charge if you will.

So the energy is getting used.

[RichardCoulter]

You make a very good point there Stephen.

[qasdfdsaq]

Originally Posted by RichardCoulter

However, I was told yesterday that newer technology means that a lot less power is used/wasted in the same situation these days, so it's not worth bothering any more.

Does anybody know if this is true?

If by newer technology you mean anything made in the last 100 years, then yeah, sure.

---------- Post added at 19:22 ---------- Previous post was at 19:19 ----------

Originally Posted by Kymmy

Linear transformers (old style) are inefficient (due to the way that the regulator circuit dumps the excess voltage) even when there's no current draw so yes there was loss but not really a great deal unless you're talking about 60-100 amp 12v PSU's that I regularly use (mainly for radio applications due to less interference)

Even then, it draws less energy when there's no load than when there is. So while they're inefficient, it's still untrue that the same power is used when not charging.

Switch mode (new style) has actually been around for 40 years and 99.99999999% of PC's ever produced have used one. They are more efficient as they can turn off the circuit when no draw is detected by using an even smaller sub circuit. It's likely that for the last 20 years you've been using this type of PSU to charge your phone, run a laptop so not really newer tech.

Slightly less than 20 years. There were still non-SMPS power supplies in the late 90's/early 2000's. Pretty much all desktop laptop and phones do now use SMPS though, with some reaching over 95% efficiency.

---------- Post added at 19:24 ---------- Previous post was at 19:22 ----------

Originally Posted by RichardCoulter

This article says that leaving the charger plugged in uses a matter of pennies a year, but that the real waste is people leaving their devices plugged in after the device has fully charged- this wastes enough energy to heat a bath every year.

Having a phone in the first place wastes enough energy to heat a bath every year, so what?

If you unplugged your phone when it was full your battery would be partly drained in the morning so you'd have to charge it more often. The same amount of power goes into the phone either way. It's no more a waste than not turning your phone off overnight. Your phone is going to use power anytime it's on.

---------- Post added at 19:25 ---------- Previous post was at 19:24 ----------

Originally Posted by Stephen

I don't think its a waste as most devices once up to 100% stop charging so the battery drops a bit then tops up the battery continuously. Trickle charge if you will.

So the energy is getting used.

Some wireless chargers are a bit dodgy in respect, it still delivers full power after the battery is full so it just gets converted into heat on the pads themselves.

[Taf]

When the battery voltage equals the charger voltage, current stops flowing.

Normally a good thing, but some chargers supply higher voltages than the battery is designed to be held at for prolonged periods, so overheating can occur within the battery. And that can be disastrous in the extreme, so many chargers have timers and/or heat sensors to cut off supply altogether.

[qasdfdsaq]

Pretty much all Li-Ion chargers supply higher voltages than the battery is designed to be held for.

That's a basic requirement for constant-current charging to work.

[nashville]

Interesting

[RichardCoulter]

A friend leaves the black plug of her charger in the socket and disconnects it by unplugging the power lead from the plug itself.

Does this draw any electricity?

[Stephen]

Why pull the cable out?? That is a waste of time if the plug is still there.

[techguyone]

Prob a USB phone charger with the USB end removable.

If there's nothing drawing power, it shouldn't be using anything, even when drawing power it's using pennies though.