The other day I was chatting to someone about my Jackery Solar Generator set up, and the subject got onto how much money you can save.
“I bet you could save a lot of money using that to charge up your iPhone!”
I’d never thought about it, so I decided to run the numbers.
The iPhone I’m using is an iPhone 11 Pro Max, and its battery has a capacity of 15.04 watt-hour.
Now let’s assume some assumptions. First, the battery has a lifespan of 500 recharge cycles, which means that over that time, it has slurped in 7,500 wh (watt-hours of power, or 7.5 kwh (kilowatt-hours) of power.
Let’s now assume that the charging system is 90 percent efficient, which means that the battery has taken in about 8.3 kwh of power.
In the US, the average cost of 1 kwh of power is about 12 cents, so over its entire lifespan, that iPhone has cost a dollar.
Let’s do the same for a MacBook Pro. The latest M1 13-inch MacBook Pro has a 58.2 wh battery and is good for 1,000 recharge cycles.
Again, assuming 90 percent efficiency in charging, and that power is the average 12 cents, that MacBook Pro will cost (assuming it’s running purely on battery power) under $8 to run.
Let’s also put this in the context of the average US residential utility customer, who uses about 900 kwh of power per month.