Understanding Energy
Imagine every appliance below is borrowing energy from a big Tesla-style EV battery pack (the kind that holds about 75–100 kWh in a real car).
That battery pack is our shared “energy tank.”
Power (watts) = How fast you’re draining the car battery right now
(How many kWh the battery loses per hour at this exact moment)
| Device | Power rating | How fast it empties a 100 kWh car battery |
| Phone charger | 10 W | Loses 0.01 kWh per hour → would take 10,000 hours (over a year) to empty the car |
| LED bulb | 100 W | 0.1 kWh per hour → 1,000 hours (42 days) to empty |
| Typical electric heater | 1,500–2,000 W |
1.5–2 kWh per hour → drains the whole car battery in 50–65 hours of use |
| Electric oven | 4,000–5,000 W| 4–5 kWh per hour → kills the car battery in just 20 hours |
| Fast charger for the car itself | 11,000 W (11 kW) | Adds (or removes, if reversed) 11 kWh every hour |
Energy (kilowatt-hours, kWh) = How many “car battery percent” you actually used up
1 kWh = 1% of a typical 100 kWh electric car battery
(or roughly 1.3% of a 75 kWh battery)
Real-life examples:
- Run a 2,000 W portable heater for 5 hours → 10 kWh used → you just burned 10% of a Tesla’s battery to stay warm.
- Leave a 100 W light bulb on for 10 hours → 1 kWh → only 1% of the car battery. Barely noticeable.
- Drive a Tesla Model 3 about 4–5 miles on a cold day with the heater blasting → also ~1 kWh. Same as leaving ten 100 W bulbs on all day.
- One full charge of an average electric car (75 kWh) = the same energy as running a 2,000 W heater non-stop for almost 38 hours straight.
“Watts tell you how fast you’re sucking a car battery flat right now, and a kilowatt-hour is simply one percent of a big EV battery — so when your heater uses 10 kWh this evening, you’ve just spent the same energy it takes to drive an electric car 30–40 miles.”
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