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> because so many people get this wrong. All these terms are just so unintuitive for a mere mortal like me. Energy? Power? The difference between those two wo
by quectophoton 2y ago
> because so many people get this wrong.
All these terms are just so unintuitive for a mere mortal like me.
Energy? Power? The difference between those two words has as much importance to the common person as the difference between "empathy" vs "compassion", or "theory" vs "hypothesis", or "less" vs "fewer".
kW being a "stuff over time", but kWh being "amount of stuff"? I don't doubt the math checks out if you expand all units, but I'm as dumb as a wet rock so it took me a while to get this.
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If people wanted me to understand this way sooner, they should have started asking me to think in terms of "kcal" (kilocalories).
At least I know that kcal is an "amount of stuff" because it's something you hear if you talk about food. And there's no mention of "hour" anywhere in the name (like with "kWh"), so the name doesn't have anything misleading.
Then just tell me that "860.421kcal/h = 1kW" (the numbers don't really matter), and ask me to solve for kcal.
When I move the "h" from the left to the right, and the equation becomes "860.421kcal = 1kW * h", everything will click.
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Food has kcal, so kcal is something that can be stored. When the equation has "kcal" on the left, it has "kW * h" on the right, so that means batteries store "kW * h".
When I think of "kW" alone, I will remember that the "* h" moved to the left side and became "/h".
I might forget stuff, but I know what food is, and I know that there exists an equation, at one side there's "kcal", at the other side there's "kW", and there's an "h" somewhere in there.
And "kcal * h" will look wrong af, so I will remember that if the "h" at the left side, it will be "kcal/h".
Result: Now I have an intuition for this.
(EDIT: Escaping, and add some separators to hopefully make the comment easier to read.)
- IshKebab 2y ago> All these terms are just so unintuitive for a mere mortal like me. Energy? Power? Yeah in fairness I think most people never have to deal with these units and they're used interchangeably colloquially. kW = power. This is a rate of work. How quickly work is happening. Intuitively, cycling hard = high power, cycling with low effort = low power. kWh = energy. 1 kWh is literally 1kW for an hour. If you are cycling pretty hard with a power of 0.1 kW for 10 hours, you have generated 1 kWh (0.1 * 10). If you cycle inhumanly hard (0.2 kW) for 3 hours you have generated 0.6 kWh (0.2 * 3). That's it. Now some examples: * Solar panel peak power. This is the maximum power output of the solar panels. For cycling it would be the hardest you can possibly cycle. Apparently the record for cycling is 2.7 kW! (But not for very long; unlike solar panels people get tired.) * Battery capacity. This is in kWh. They store a finite amount of energy. If you have a battery containing 10 kWh you can eek it out slowly - if you only draw 0.1kW from it it will last 100 hours. Or you can dump all the energy in half an hour and it will output 20 kW. The only really complicated one is battery factory output capacity, which approximately 0% of journalists understand. This is measured in Watts... because if you produce 1kWh batteries, and you make one per hour... 1kWh/ 1h is 1 kW! In other words if the batteries from the factory magically came out fully charged and you just used them as a power station without recharging them, then how much power could that power station provide? Yeah that one is a bit confusing.