How to choose a compact external battery for MacBook

1. See only batteries with the USB-C

With small external battery officially work only with Apple laptops USB-C ports. This MacBook 2015 and newer MacBook Pro 2016 and newer, as well as the MacBook Air in 2018.

Sometimes, there are options for sale for more than earlier Apple laptops, which are charged by a MagSafe and MagSafe 2 magnetic ports. But the company does not certify such: their use may damage the charging port and built-in battery.

Instead of a compact external battery in this case it is better to take a larger model with a high-grade receptacles. By this charging MacBook, you can connect a standard power supply. But in a small backpack or bag city such a decision will not fit.

To charge the new MacBook laptop battery with a suitable USB-C. It can be connected to a laptop via the bundled Apple cable. In this case, the standard power supply unit is suitable for fast charging of the battery.

Only USB-C supports the new power standard called Power Delivery. Without him, the external battery is not enough power to charge any of the new MacBook.

2. Check the support of the new food standard

Look for Power Delivery standard mark on the box body of the device, in the official specifications on the manufacturer's website or in the reviews.

Power Delivery - is a new standard USB power with increased power. He needed to charge laptops and other production devices.

With him running popular external batteries Xiaomi ZMI 10, Hiper MPX20000, Aukey PB-Y7, InterStep PB2018PD and others.

Using Power Delivery device requests the external battery required power. It may be different, depending on the intensity of the work. If he can give it, the device is fully charged.

Power Delivery can be operated with a current intensity of up to 5 A, the voltage to 20 V and up to 100 watts. Standard launched in 2012, and in 2014 decided to use only with the USB-C ports. In the external battery standard began to appear after the release of the new MacBook in 2015.

3. You will be examined with the maximum power

Manufacturers specify the maximum power on the box or external battery case.

Generally it is far from 100 W - maximum value, which supports Power Delivery. For example, an external battery Aukey PB-Y7 through the USB-C may issue no more than 30 watts.

12-inch MacBook and the new MacBook Air at maximum load consumes 30 W, 13-inch MacBook Pro need 61 W, and 15-inch - 87 watts.

This does not mean that the external battery 30 W not get used to the MacBook Pro.

If you connect Aukey PB-Y7 to the MacBook Pro at rest or at low load, the laptop can be charged. If we load it in full, it will just slowly discharged.

If you plug this external battery to the discharged MacBook Pro, and then heavily load the last laptop is turned off. But you can wait until the computer is charged to 20-30%, and only then to load it.

4. Determine the actual battery capacity

Most often, external battery manufacturers indicate their capacity in milliamp-hours. It is called a charge and is calculated based on the standard voltage for the battery inside the device - it is 3.7 V.

When a voltage of 3.7 V at Xiaomi ZMI 10 - 20 000 mA⋅ch. But if you raise it to 5 V as the iPhone power adapter, the charge will drop to 12,000 mA⋅ch. But with 7.2, he has already reached 10,000 mA⋅ch. The higher the voltage, the smaller the charge, therefore making conclusions about the battery capacity can not be on such a basis.

When we do not know the voltage, with which the external battery will be used to assess the capacity better not take charge, and energy. It is measured in watt-hours, and is usually indicated on the package or box: Xiaomi ZMI at 10 - 72 Vt⋅ch, at Hiper MPX20000 - 74 Vt⋅ch.

If the manufacturer does not have an external battery capacity in watt-hours, you can roughly estimate its approximate value.

Battery capacity in Wh = charge in milliampere-hours × volts / 1000.

These values ​​must be specified in the specifications of the external battery in small print.

Result in Wh not be precise, since external batteries do not give stable claimed voltage and it is reduced during the discharge time. However, this figure will allow to estimate, what percentage to zero will charge the MacBook.

During the evaluation of the external battery capacity is also necessary to consider its efficiency (COP).

Some of the energy will be spent on heating and is lost during transmission, so to MacBook eventually will reach no more than 70-80%: multiply the watt-hours of battery at 0.7-0.8.

MacBook Battery Capacity:

• MacBook 12 "- 41.4 W ∙ h;
• MacBook Air with Retina-display - 50.3 W ∙ h;
• MacBook Pro 13 ", without Touch Bar - 54,5 W ∙ h;
• MacBook Pro 13 "with Touch Bar - 58 W ∙ h;
• MacBook Pro 15 "- 83.6 W ∙ h.

Given the efficiency of 74 Vt⋅ch battery can give 51,8-59,2 Vt⋅ch.

He's just completely discharged to zero charge 12-inch MacBook and MacBook Air with the Retina-display. batteries other laptops when connected to such a battery can not reach from 0 to 100%.

5. Experience the additional capabilities of the device

When choosing a portable external battery for MacBook also note the number of additional ports, which will be useful for charging smartphones and other mobile devices.

For example, InterStep PB2018PD, apart from the standard Power Delivery, also works with the standards of fast charging smartphones Samsung AFC, Huawei FCP and Quick Charge 3.0. It is possible to pay attention, if you are using devices with the support of one of these technologies.