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> You can even charge your MBP and phone together from one of those generic portable USB-C backup batteries That is kind of cool -- but how many batteries is i

> You can even charge your MBP and phone together from one of those generic portable USB-C backup batteries That is kind of cool -- but how many batteries is it going to take, in practice, to juice up a MBP from empty?

lobster_johnson 10y ago
I don't know the specs of the new MBPs, but my mid-2015 MBP's battery is 7530 mAh at full charge. You can get portable charger batteries that are much more than that these days; this one [1] is 26,800 mAh, which in theory could charge my MBP 3.5 times. In practice, less than that, but still probably at least two full charges. [1] https://www.amazon.com/Portable-Charger-RAVPower-26800mAh-Recharged/dp/B01LRQDAEI https://www.amazon.com/Portable-Charger-RAVPower-26800mAh-Re...
- dancek 10y ago
  You can't directly compare mAh values, as they're an unit of electric charge. The amount of energy depends on voltage, too. Power bank manufacturers are basically running a marketing scam; the batteries they sell have 3.7V while USB uses 5V. What's more, the MBP battery voltage is something around 12V. So the 26,800 mAh power bank has a capacity of 26,800 mAh * 3.7V = 99,600 mWh = 99.6 Wh of energy. Meanwhile, the 15" MBP has a 76 Wh battery. So theoretically you can do about 1.3 charges; realistically I'd say one full charge.
- leoedin 10y ago
  A Macbook Pro (or indeed any laptop) battery operates at a voltage much higher than that of your phone or a powerbank. The actual power available from the battery (in Wh) can therefore only be compared with another battery's quoted capacity if the voltage is taken into account. A MBP battery might be a 11.1V battery, while a portable power bank capacity is almost certainly quoted as a summation of the capacities of the 3.7V cells inside. The capacity of the power bank must therefore be divided by 3 to give the equivalent capacity in mAh at 11.1V.
- curried_haskell 10y ago
  That's not how electricity works.
thatcat 10y ago
The largest Mi power bank is 16000+ mAh, smallest is 5000. MPB is 6000, phone is about 3500. So you could get about 1 or 2 charges depending on battery size of course.
- dancek 10y ago
  See my reply to a sibling comment [1]. A 16,000 mAh power bank is about 75% the capacity of the 15" MBP battery.
- curried_haskell 10y ago
  You're looking at the wrong numbers. What are the watt hours?
falcolas 10y ago
The macs battery is about 50 or so watt hours, your average $40 external battery is around 70. Disregarding inefficiencies of charging a battery from a battery, about one. Realistically, closer to two. To do your own math, it's mAh * voltage / 1000
- santaclaus 10y ago
  > To do your own math, it's mAh * voltage / 1000 The 1 / 1000 is a millisecond? Otherwise the units work out to power and not potential energy?
  - detaro 10y ago
    1000 mAh * 1 V / 1000 = 1 Ah * 1 V = 1 Wh Wh is energy, dividing through time would be power.

lobster_johnson 10y ago

I don't know the specs of the new MBPs, but my mid-2015 MBP's battery is 7530 mAh at full charge. You can get portable charger batteries that are much more than that these days; this one [1] is 26,800 mAh, which in theory could charge my MBP 3.5 times. In practice, less than that, but still probably at least two full charges. [1] https://www.amazon.com/Portable-Charger-RAVPower-26800mAh-Recharged/dp/B01LRQDAEI https://www.amazon.com/Portable-Charger-RAVPower-26800mAh-Re...

dancek 10y ago
You can't directly compare mAh values, as they're an unit of electric charge. The amount of energy depends on voltage, too. Power bank manufacturers are basically running a marketing scam; the batteries they sell have 3.7V while USB uses 5V. What's more, the MBP battery voltage is something around 12V. So the 26,800 mAh power bank has a capacity of 26,800 mAh * 3.7V = 99,600 mWh = 99.6 Wh of energy. Meanwhile, the 15" MBP has a 76 Wh battery. So theoretically you can do about 1.3 charges; realistically I'd say one full charge.
leoedin 10y ago
A Macbook Pro (or indeed any laptop) battery operates at a voltage much higher than that of your phone or a powerbank. The actual power available from the battery (in Wh) can therefore only be compared with another battery's quoted capacity if the voltage is taken into account. A MBP battery might be a 11.1V battery, while a portable power bank capacity is almost certainly quoted as a summation of the capacities of the 3.7V cells inside. The capacity of the power bank must therefore be divided by 3 to give the equivalent capacity in mAh at 11.1V.
curried_haskell 10y ago
That's not how electricity works.

thatcat 10y ago

The largest Mi power bank is 16000+ mAh, smallest is 5000. MPB is 6000, phone is about 3500. So you could get about 1 or 2 charges depending on battery size of course.

dancek 10y ago
See my reply to a sibling comment [1]. A 16,000 mAh power bank is about 75% the capacity of the 15" MBP battery.
curried_haskell 10y ago
You're looking at the wrong numbers. What are the watt hours?

falcolas 10y ago

The macs battery is about 50 or so watt hours, your average $40 external battery is around 70. Disregarding inefficiencies of charging a battery from a battery, about one. Realistically, closer to two. To do your own math, it's mAh * voltage / 1000

santaclaus 10y ago
> To do your own math, it's mAh * voltage / 1000 The 1 / 1000 is a millisecond? Otherwise the units work out to power and not potential energy?
- detaro 10y ago
  1000 mAh * 1 V / 1000 = 1 Ah * 1 V = 1 Wh Wh is energy, dividing through time would be power.