On my van, I have a 12V 100Ah battery.

Let’s say I have a 100W hair dryer that I run through a power inverter. For how many hours can I run it, before the battery capacity ends?

The formula to use is Wh / V, which in this case means

100Wh/12V = 8,333Ah

1 watt-hour is 1 watt of power expended for 1 hour

Since the battery is 100Ah, I can run it for 12 hours (100Ah / 8,333Ah).

If I had a device that consumed 200W, I could run it for 6 hours.

This assuming the battery is 100% and I can consume 100% of its power, what almost happens with a LiFePo4 battery, but not for regular lead-acid batteries.

Lessons in this unit:

0:	Introduction
1:	Introduction to Electronics
2:	Analog vs digital
3:	Current
4:	Voltage
5:	Vcc, ground, ...
6:	Resistance
7:	Short Circuit
8:	Your first circuit
9:	Prototyping using breadboards
10:	Using a multimeter
11:	Measuring voltage, current and resistance using a multimeter
12:	Milli Micro Nano Pico
13:	▶︎ Calculating Ah from Watts
14:	Electronic Project: Build a voltage divider
15:	Electronic Project: Build a LED dimmer with a potentiometer