Oct price cap increase likely to push energy bill to over £10k... for a family of 4...

Mstty

If it's of interest I know you use an iMac but for a comparison my Dell laptop just used a total of .185 kW over 9 hours so on our rate of 29.24p kwh about 5.4p for the day. Estimated £12.15 for the year taking into account holidays etc

If you have a spare laptop about for even half the work there is a big saving to be made over desktop machines apple/windows or other.

Vincero

xeny said:

An absolutely inconsequential to most people, but not zero.
What people would find more shocking is that for the average smartphone user they probably use around 100 kWh a year charging their phone....

273 Wh/day ? That seems a bit excessive.

It is, should have been about 4kWh

Vincero

k_man said:

Vincero said:

michaels said:

You need to think about what is material.  Pretty much anything that runs off a battery (except for a car) will be negligible when charging or using, for example a phone on a charger will use pretty much zero to charge and as close to zero as makes no difference when charged whether plugged in or not.

The main tip is to do the touch test.  Waste electricity is heat so if a set top box, charger brick etc is moderately warm then it is consuming power, otherwise don't worry about it.

Agreed, but I tried to be as factual as possible. It would be wrong to say there is absolutely no vampire power from some charger devices when there is nothing attached.

In terms of a phone left on a charger, assuming it uses say 15 mAh to keep itself in standby with cell and WiFi connections live and it was left connected and unused like that for a year, would use at least 486 Wh in a year. It would likely be a bit higher (which is why I assumed 50mAh in example) for a phone someone actually uses properly with background apps, etc.

An absolutely inconsequential to most people, but not zero.
What people would find more shocking is that for the average smartphone user they probably use around 100 kWh a year charging their phone....

Can you confirm you use of mAh? Over what period?

Regarding standby power while plugged in, wouldn't the standby power get used whether the phone is left on the charger or not, but just be running down the battery in the latter. The battery then needs to be charged.
Unless you are comparing phone left plugged in Vs phone unplugged and turned off?

And, as above, can you check your maths on the 100 kWh per year?
Most mobiles have batteries of around 4000mAh.
At a nominal 5V (to make the maths easier) is 20Wh.
Note this matches the typical 1 - 2 hour charges at 10 - 20W (2 to 4A at 5V).

Assuming charged once per day gives approx 7 kWh per year.

To get to 100 kWh, it would need to be charging at full rate almost 24/7.

Yeah, I got the 100kWh wrong as I was getting a bit punchy with calculator so forgot to divide 24 hours. For some reason I calculated average use over a day rather than just calculate the battery Wh rating and multiply that by 365 (assuming no losses). Should be around 4 kWh over a year if you generously ignore any conversion losses (so assume nominal 3.5-4.3V for Li-ion battery) which is being generous (although the wife is glued to her phone so maybe she does manage 100).

In terms of mAh usage, you can monitor this on your device with various apps. But if you assume the average smartphone left alone doing nothing could maybe stay in standby for up to 2 weeks (I've seen almost 10 days managed before on an old Sony Xperia with 3Ah battery and they weren't known for being the best at optimisation), so with newer phones pushing up battery capacity and more efficient tech 2 weeks may be doable for some.

E.g. 3000mAh / 216h = 14mA average current. Of course that is with it doing nothing at all - literally no apps set up or running.

My current phone is telling me with screen off it averages about 30mAh usage, but that has apps like WhatsApp running in the background.

So standby calc is: 15mAh x 3.7V = 55.5mWh x 24(day) x 365(year) = 486 Wh

MariaAH

Mstty said:

If it's of interest I know you use an iMac but for a comparison my Dell laptop just used a total of .185 kW over 9 hours so on our rate of 29.24p kwh about 5.4p for the day. Estimated £12.15 for the year taking into account holidays etc

If you have a spare laptop about for even half the work there is a big saving to be made over desktop machines apple/windows or other.

I use a 27 inch iMac, although I do have access to 14 inch Acer laptop. As a migraine sufferer who wears glasses for PC work, I can comfortably work on the iMac all day, plus my desk and office chair are set up for optimal position. It also has the benefit of being able to have documents side by side which suits what I do for my work. I really could not work my 14 inch laptop all day without getting a migraine, not to mention neck and back pain. I recently had a back issue, lots of chiropractor appointments and a new ergonomic desk chair.

Why do I have a 14 inch laptop - its provided by my employer...when I do go into the office, I hot desk and plug it into a docking station where I have 2 large monitors, keyboard and mouse connected. I could go into the office more, but with travelling time and the cost of energy for my EV, it would negate any savings.

Mstty

The laptop plugged into monitors at home would likey be cheaper than the iMac.

Plus, I may be wrong, but using a personal iMac for business then sending those files into and out of work is prohibited by most companies these days.

A better and cheaper to run setup would be work laptop and 2 screen setup to mimic work.

If the iMac is work provided or on their you work within a protected company cloud ignore everything above you have explained why it is better for you and not an area you would look to save on👍

Probably only a small saving anyway I think the average 27" iMac is 100w in average use.

However don't underestimate the smallest of saving 100w saved equals 876kW and that could soon be over £500 a year.

xeny

A modern iMac pretty much is a large monitor with a laptop embedded, so something doesn't quite add up - what model is it exactly?

k_man

Vincero said:

k_man said:

Vincero said:

michaels said:

You need to think about what is material.  Pretty much anything that runs off a battery (except for a car) will be negligible when charging or using, for example a phone on a charger will use pretty much zero to charge and as close to zero as makes no difference when charged whether plugged in or not.

The main tip is to do the touch test.  Waste electricity is heat so if a set top box, charger brick etc is moderately warm then it is consuming power, otherwise don't worry about it.

Agreed, but I tried to be as factual as possible. It would be wrong to say there is absolutely no vampire power from some charger devices when there is nothing attached.

In terms of a phone left on a charger, assuming it uses say 15 mAh to keep itself in standby with cell and WiFi connections live and it was left connected and unused like that for a year, would use at least 486 Wh in a year. It would likely be a bit higher (which is why I assumed 50mAh in example) for a phone someone actually uses properly with background apps, etc.

An absolutely inconsequential to most people, but not zero.
What people would find more shocking is that for the average smartphone user they probably use around 100 kWh a year charging their phone....

Can you confirm you use of mAh? Over what period?

Regarding standby power while plugged in, wouldn't the standby power get used whether the phone is left on the charger or not, but just be running down the battery in the latter. The battery then needs to be charged.
Unless you are comparing phone left plugged in Vs phone unplugged and turned off?

And, as above, can you check your maths on the 100 kWh per year?
Most mobiles have batteries of around 4000mAh.
At a nominal 5V (to make the maths easier) is 20Wh.
Note this matches the typical 1 - 2 hour charges at 10 - 20W (2 to 4A at 5V).

Assuming charged once per day gives approx 7 kWh per year.

To get to 100 kWh, it would need to be charging at full rate almost 24/7.

Yeah, I got the 100kWh wrong as I was getting a bit punchy with calculator so forgot to divide 24 hours. For some reason I calculated average use over a day rather than just calculate the battery Wh rating and multiply that by 365 (assuming no losses). Should be around 4 kWh over a year if you generously ignore any conversion losses (so assume nominal 3.5-4.3V for Li-ion battery) which is being generous (although the wife is glued to her phone so maybe she does manage 100).

In terms of mAh usage, you can monitor this on your device with various apps. But if you assume the average smartphone left alone doing nothing could maybe stay in standby for up to 2 weeks (I've seen almost 10 days managed before on an old Sony Xperia with 3Ah battery and they weren't known for being the best at optimisation), so with newer phones pushing up battery capacity and more efficient tech 2 weeks may be doable for some.

E.g. 3000mAh / 216h = 14mA average current. Of course that is with it doing nothing at all - literally no apps set up or running.

My current phone is telling me with screen off it averages about 30mAh usage, but that has apps like WhatsApp running in the background.

So standby calc is: 15mAh x 3.7V = 55.5mWh x 24(day) x 365(year) = 486 Wh

That makes more sense, but I think you may have some rogue hs

Power usage is usually quoted in W

Energy usage is usually in Wh

Current is in A (or mA)

Battery capacity (annoyingly) is in mAh

As such your phone with the screen off averages 30mA power usage, or 30mAh per hour (the latter being actually the same as the former)


</pendant>

MariaAH

Mstty said:

The laptop plugged into monitors at home would likey be cheaper than the iMac.

Plus, I may be wrong, but using a personal iMac for business then sending those files into and out of work is prohibited by most companies these days.

A better and cheaper to run setup would be work laptop and 2 screen setup to mimic work.

If the iMac is work provided or on their you work within a protected company cloud ignore everything above you have explained why it is better for you and not an area you would look to save on👍

Probably only a small saving anyway I think the average 27" iMac is 100w in average use.

However don't underestimate the smallest of saving 100w saved equals 876kW and that could soon be over £500 a year.

I log into a protected Google workspace for work so all on company cloud. None of my 'work' is held locally on my iMac.
Whilst it would be cheaper in terms kWh for 2 screen setup...not if I have to buy 2 new monitors, a docking station, mouse, keyboard, webcam etc to replace the iMac. Without going into details about what I do for work, having the 27 in screen makes doing my job easier and more efficient, and is less likely to trigger my migraines. The migraine issue was one of the reasons I bought the iMac 4 years ago.

Mstty

Yep as I said that's explained and not changeable👍

Don't suppose you've managed to monitor the fridge freezer yet that one will be interesting due to age a couple posted on here recently have been eating 2-3kWh a day.

MariaAH

xeny said:

A modern iMac pretty much is a large monitor with a laptop embedded, so something doesn't quite add up - what model is it exactly?

The nearest I can find (on Apple website) to state the kWh is 


But this is not exact match as mine is 3.4GHz Quad-core i5, but was my best guess of consumption until I can measure it later, once I have finished monitoring son's PC with the TP link monitors.