0
\$\begingroup\$

Disclaimer: I do understand that depending on the load the "power adapters" or chargers would pull a completely different values, so this question is about the theoretical "peak".

I have a laptop charger rated for 130 W output: 19.5 V x 6.7 A = 130.65 W

At the same time the "Input" section says: 100-240 V~2.5 A.

Given that I have ~230 V in the mains, does that mean that at the peak load the charger would pull whole 575 W from the mains (with ECE as low as 22.7 %)? I.e. is the "wattage" pulled from the mains depending on input (intuitive but expensive :( ) or output (counterintuitive)?

\$\endgroup\$
0

1 Answer 1

3
\$\begingroup\$

Given that I have ~230V in the mains, does that mean that at the peak load the charger would pull whole 575W from the mains (with ECE as low as 22.7%)?

No. The 2.5 A are just a worst case, "fused" current. It might apparent power, with no real power consumption at all.

I.e. is the "wattage" pulled from the mains depending on Input (intuitive but expensive :( ) or Output (counterintuitive)?

super counterintuitive to assume it depends on the input, because then the thing would always use the same power.

\$\endgroup\$
3
  • \$\begingroup\$ So - if I'm reading you right, if it works at full capacity for a theoretical hour, I will pay for neither 130Wh, nor 575Whr, but something in between? \$\endgroup\$ Aug 30 at 13:39
  • 3
    \$\begingroup\$ the 2.5 A are completely meaningless to your power consumption. Ignore them, and ignore the 575 W that you derived from them. You'd be paying for what your laptop actually draws in power, plus the overhead due to efficiency not being 100%, but (for a modern laptop charger) somewhere between 80% and 100% (so, 100% to 120% of that laptop power consumption). Energy conservation holds, don't forget that the universe won't let you "disappear" power. \$\endgroup\$ Aug 30 at 13:43
  • \$\begingroup\$ Your laptop won't be able to draw the maximum power for hours on end, as (nearly) all the power it draws is, in the end, used to heat up the device, aside from the amount that goes into charging a battery that must be full at some point. Again, intuitive is that you need to put in the power to a system that it consumes, not that you need to consume all the power your national power grid, or your laptop charger, could provide, potentially. \$\endgroup\$ Aug 30 at 13:44

Not the answer you're looking for? Browse other questions tagged or ask your own question.