Kempower unveiled its new charger […] that can dispense 1.2 mW
At 1.2 mW, my electric car would need roughly 8.5 millenia to charge. At its average consumption, every kilometer driven would require 35 years of recharging. Like, I don’t want to sound too picky, but I guess I’d rather walk tbh.
A watt is a unit of power. It’s an energy rate, it involves time. It’s 1 joule per second (J/s).
A watt-hour is the amount of energy delivered at a rate of 1 watt over the course of one hour. (J/s x h). And here we get into the trouble already. (The kilowatt-hour is just 1,000 watt-hours, that’s not the source of the trouble.)
Now we have a unit of energy (the watt-hour) that includes the names of a unit of power (watt, which is a rate) and a unit of time (hour) but the watt-hour (and the kilowatt-hour) measures neither of those things. The watt-hour is defined as ((energy / time unit) x different time unit). It’s insane. Even though the time units should cancel out, we keep the ghost of both time units in the name, to no purpose. It works out to just joules; 1 Wh is 3,600 joules. 1 kWh is 3,600,000 joules.
It is exactly analogous to measuring distance in “meter-per-second-minutes,” when you’ve got meters right there.
At 1.2 mW, my electric car would need roughly 8.5 millenia to charge. At its average consumption, every kilometer driven would require 35 years of recharging. Like, I don’t want to sound too picky, but I guess I’d rather walk tbh.
Almost no one can keep kW and kWh straight, why would you think they could understand MW?
KWh is super dumb, though, like they were trying for maximum confusion when they invented it.
Is it?
Would you measure distance in “1,000 meter per second minutes?”
I don’t understand.
Well, precisely!
A watt is a unit of power. It’s an energy rate, it involves time. It’s 1 joule per second (J/s).
A watt-hour is the amount of energy delivered at a rate of 1 watt over the course of one hour. (J/s x h). And here we get into the trouble already. (The kilowatt-hour is just 1,000 watt-hours, that’s not the source of the trouble.)
Now we have a unit of energy (the watt-hour) that includes the names of a unit of power (watt, which is a rate) and a unit of time (hour) but the watt-hour (and the kilowatt-hour) measures neither of those things. The watt-hour is defined as ((energy / time unit) x different time unit). It’s insane. Even though the time units should cancel out, we keep the ghost of both time units in the name, to no purpose. It works out to just joules; 1 Wh is 3,600 joules. 1 kWh is 3,600,000 joules.
It is exactly analogous to measuring distance in “meter-per-second-minutes,” when you’ve got meters right there.
We should have stuck with MJ and MJ/s. No need to get W or h involved.
kW and kWh helps understanding charging speed/capacity better than MJ and MJ/s.
Btw. 1 MJ/s = 1 MW, but you surely know that.