# How much electrical is required to charge the latest MacBook Pro 13"

My Late 2016 (the newest model) was purchased for use on a sailboat. I'm beginning to prepare a power use spreadsheet that totals the amp-hours, watts and time required for all of the electrical items on board. This is required since many of the other electrical systems are designed around the electric power needed. Thanks.

## 1 Answer from the Community

• This may not be the greatest answer, so take it with a giant grain of salt.
I assume you're asking about how much 120V power you need (not the DC going into the macbook).

Two methods. Both require a "guess" about charging efficiency.

1. Battery holds XX mW-hours. In a perfect world, just divide this by 120V and that's how many mA hours (or by 120,000 for amp-hours) the battery holds. Then, take a guess at charging efficiency and increase the amp-hours accordingly (my wild guess is 75% so I'd divide by 0.75).

2. Look on the power adapter case. It rates the input and output (very fine print). Your charger should never draw more than that input rating (120V @ XXXX AMPS). Not sure if the 60W name of the adapter is an output power our input power. But if it is input, the most that the adapter would ever draw from the 120 supply would be 0.5A while charging.

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