The Cost of Charging a Mobile - Car vs home

[mollytherocker]

One for the mathematicians! OK, not that interesting but something I have often wondered.

I would assume that it costs a lot more charging a phone in your car - Fuel cost vs electricity. Is this right? And if so, by how much?

Furthermore, I wonder how much revenue is earned by the fuel companies from charging the increasing amount of electrical gadgets we have? It could be billions?

And finally, the effect on MPG if say, you are constantly charging at least one device. 1% maybe?

MTR

[cuprabob]

Just switch off the radio and save yourself some money :-)

Solution is always charge your phone at work.

[mollytherocker]

cuprabob said:

Just switch off the radio and save yourself some money :-)

Solution is always charge your phone at work.

I dont need a solution. I am just interested in the subject.

MTR

[iva cosworth]

Well it be on to this.

You need to get out more

[eldar]

mollytherocker said:

One for the mathematicians! OK, not that interesting but something I have often wondered.

I would assume that it costs a lot more charging a phone in your car - Fuel cost vs electricity. Is this right? And if so, by how much?

Furthermore, I wonder how much revenue is earned by the fuel companies from charging the increasing amount of electrical gadgets we have? It could be billions?

And finally, the effect on MPG if say, you are constantly charging at least one device. 1% maybe?

MTR

Output to charge phone .08A at 5v = 4w. single sidelight 5w at 12v = .4A. So you use .2 of a single sidelight. About 0.000132% more fuel, accounting for generator inefficiencies, or 8 inches per mile. Every little helps

[sparks_E39]

Charging my phone/satnav and having the radio on in my car makes absolutely no difference at all. If it does then it's so little I haven't noticed. Even with the air con on it only takes off about 1 mpg, if that.

[mollytherocker]

sparks_E39 said:

Charging my phone/satnav and having the radio on in my car makes absolutely no difference at all. If it does then it's so little I haven't noticed.

In that case, you have discovered a source of free energy!

MTR

[sparks_E39]

mollytherocker said:

In that case, you have discovered a source of free energy!

MTR

Not quite, it's just so little, it hardly makes a difference.

[eldar]

mollytherocker said:

In that case, you have discovered a source of free energy!

MTR

Or an energy consumption too small to be measured without expensive equipment.

[Funk]

mollytherocker said:

MTR

Here's a trickier one...

Why do people sign their posts when it clearly shows who they are a few lines higher up the page?

How much of the internet are they wasting, and how much more bandwidth do I waste having to download it?

[mollytherocker]

Funk said:

mollytherocker said:

MTR

Here's a trickier one...

Why do people sign their posts when it clearly shows who they are a few lines higher up the page?

How much of the internet are they wasting, and how much more bandwidth do I waste having to download it?

Not as much as those who question it?

MTR

[McSam]

eldar said:

Output to charge phone .08A at 5v = 4w. single sidelight 5w at 12v = .4A. So you use .2 of a single sidelight. About 0.000132% more fuel, accounting for generator inefficiencies, or 8 inches per mile. Every little helps

You beat me to it! But you're a factor of ten off, as 0.08 * 5 does not equal 4

To take a similar route, mine is charged at home and produces 1A at 5V, so that's 5W. If we assume a typical electricity cost of 20p/kWhr and typical charge time of two hours, the phone costs 0.2p per charge. Which is a hundred times worth avoiding pissing around with cables in my car

[mollytherocker]

McSam said:

eldar said:

Output to charge phone .08A at 5v = 4w. single sidelight 5w at 12v = .4A. So you use .2 of a single sidelight. About 0.000132% more fuel, accounting for generator inefficiencies, or 8 inches per mile. Every little helps

You beat me to it!

To take a similar route, mine is charged at home and produces 1A at 5V, so that's 5W. If we assume a typical electricity cost of 20p/kWhr and typical charge time of two hours, the phone costs 0.2p per charge. Which is a hundred times worth avoiding pissing around with cables in my car

OK, so if its 0.2p at home, how much in your car then?

MTR

[McSam]

Put it this way, switching off at the lights for thirty seconds would recoup far more.

If you consider the 5W that the charger might be consuming, then think that my engine makes 145,000W at peak power and at least 20,000W in gentle acceleration..

[mollytherocker]

McSam said:

Put it this way, switching off at the lights for thirty seconds would recoup far more.

If you consider the 5W that the charger might be consuming, then think that my engine makes 145,000W at peak power and at least 20,000W in gentle acceleration..

Yes, I am well aware that its a small number, I was just interested in the difference in percentage terms between electricity and a cars powerplant.

MTR

[McSam]

Well, there you go

A reasonable road load might be 30kW at a constant 70mph, so even if your power conversion from the alternator drive taken from the engine, through the battery to and the wiring and the power transformer to charge the phone is only 50% efficient - it should be better than this - you're adding a 10W load onto that. Or you're burning 0.0000033% more fuel!

At idle, other ancillaries will still be taking as much as 3kW - oil and water pumps, the alternator still, air conditioning - so then you have a whopping 0.000033% of your fuel going to your charger

[kambites]

Peak efficiency of your car will be about 40% and a more typical efficiency while driving will be something like 20%; power stations are up around the 50% mark but there's losses in the grid which probably make the actual fossil-fuel to electricity efficiency roughly similar.

Add in the fact that road fuel is taxed at over 100% and it'll be a lot cheaper to charge it at home.

[CK_N4S]

But we all know that sometimes (and this is certainly the case with smartphones) the damn bugger piece of crap battery will just run out. Hence keeping a charger in your car is not a bad idea - even if it is more expensive than charging the phone at home

CK

[kambites]

CK_N4S said:

But we all know that sometimes (and this is certainly the case with smartphones) the damn bugger piece of crap battery will just run out. Hence keeping a charger in your car is not a bad idea - even if it is more expensive than charging the phone at home

CK

I charge my laptop up at work, then charge my phone from my laptop.

[McHaggis]

Solution.

Charge it at work. Free...