On 2024-02-28 19:01, Alan Browne wrote:
On 2024-02-28 16:14, Alan wrote:
Do...
...the...
...math.
Screwed up big time. All of the figures in my calculation were for:
An average of 1% of charge difference (151 joules). And I omitted this
from the computation
Therefore. Given a charge range change of (say) 30% for a drive to and
from work:
the 9,269,000 Kg of CO2 emitted because of wireless charging SHOULD have
been 30X higher:
278,070,000 Kg of CO2 per year for the case as presented below.
And again: that's for 30% of charging.
Sure - based on my own testing in 2021. Anker pad v. Apple 12W charger+wire.
iPhone 11 from 20% to 74% charge: 34225 joules (W-s) using charger and wire
iPhone 11 from 24% to 77% charge: 41626 joules (w-s) using same Anker wireless charger and phone carefully centred on the charger (better than ±1mm in X and Y). Data below.
THAT IS:
634 joules per percent of change (average) wired.
v.
785 joules / percent of change (average) wireless (without a case -
which would have made it worse).
So it took 23% more energy to charge the battery over the easiest range
of about 20 - 75%.
So, if one does that 200 times per year (going to work), that comes to:
151 joules * 200 days * 1B people = 30.2E12 joules.
FOR A 1% AVERAGE AMOUNT OF CHARGE... *doh*
or 8.39 GWh lost to heat in wireless charging.
Gas engines are (at cruise) about 30% efficient, so now we're at:
28 GWh worth of gasoline ...
Until you consider the efficiency of the alternator, put at 70 to 80% by various sources. I'll use 75%:
=37.3 GWh worth of gasoline. @ 12.78 kWh/Kg of gasoline...
=2,917,000 Kg of gasoline used (for no good reason);
1 Kg of gasoline reacted with 14.7 Kg of air = 3.18 Kg of CO2 emitted
=9,269,000 Kg of CO2 emitted because of wireless charging.
Scale as you like. But it's clear that avoiding millions of Kg of CO2 emissions per year is better than putting it out there.
Esp. as it lingers for 20 - 50 years or more.
Test data.
===============
2021-11-30 iPad 12W charger
iPhone 11 Pro Wired charge
Power(W)Start End Dt Energy (Ws)
13.9 20% 25% 4.16 minutes 3475
13.9 25% 31% 5 minutes 4170
13.9 31% 37% 5 minutes 4170
13.9 37% 43% 5 minutes 4170
12.2 43% 50% 5 minutes 3660
11.8 50% 56% 5 minutes 3540
12 56% 61% 5 minutes 3600
11.8 61% 67% 5 minutes 3540
6.5 67% 74% 10 minutes 3900
34225
===============
2021-12-03 iPad 12 W charger
iPhone 11 Pro Anker pad No case (bare metal to charger)
Power(W)Start End Dt Energy (Ws)
6.1 24% 28% 7.75 minutes 2836.5
6.1 28% 34% 15 minutes 5490
6.1 34% 41% 15 minutes 5490
6.1 41% 49% 15 minutes 5490
6.2 49% 56% 15 minutes 5580
6.2 56% 63% 15 minutes 5580
6.2 63% 70% 15 minutes 5580
6.2 70% 77% 15 minutes 5580
--
“Markets can remain irrational longer than you can remain solvent.”
- John Maynard Keynes.
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