# MacBook battery VS iPad battery

Discussion in 'MacBook Pro' started by sotosoul, Mar 3, 2015.

1. Mar 3, 2015
Last edited: Mar 3, 2015

### sotosoul macrumors newbie

Joined:
Mar 28, 2012
#1
Hello, people.
The latest update of coconutBattery can provide information on the batteries of your iOS devices. Doing so, I noticed that the reported capacity of my 4th gen. iPad is higher than the capacity of my late 2013 MBPr 15"!
MBPr 15: 8440 mAh
...am I missing something here? Is the iPad's battery really bigger than the MacBook's?

EDIT: After a brief research, I found out that the units measuring the capacity of batteries are Wh (Watt-hours)
So, the capacities are 95 Wh (15") and 42,5 Wh (iPad). Almost twice as big.

2. Mar 3, 2015
Last edited: Mar 3, 2015

### ha1o2surfer macrumors 6502

Joined:
Sep 24, 2013
#2
that Wh rating is key because the Macbooks Battery is 11.1v (I think) and the iPad is 3.7v I believe. HUGE difference. So yes, you answered your own question sort of.

If the Macbook supported a battery voltage of 3.7v (which is doesn't just using the Macbook as an example) then it would have to draw almost 4 times as much amperage (at any given load) then if the macbook was using a battery that was supplying 11.1 volts. Here's an easier way to say it..

Device @ 5 volts draws 2 Amps (10 watts)
Device @ 2.5 volts draws 4 amps (10 watts)

So the iPad battery wouldn't last very long.... lol

Real Numbers:

Macbook Battery = Macbook Drawing 20 Watts @ 11.1 Volts (1.8 Amps)= Battery life of 3.5 Hours
iPad Battery = Macbook Drawing 20 watts @ 3.7 Volts (5 amps) = Battery Life of 1.5 Hours

Amps = Power (volts) / Watts.

So lets try an iPhone battery lol

Amps (x) = 3.7volts / 20 watts = (x)5 amps.
ok so the iPhone battery is 2915 mAh or 11.1wH.

5000mA / 2915mA = .5. so.. 30 minutes of battery life

Hopefully that fills in the gap!

3. ### TheMacNinja macrumors newbie

Joined:
Mar 3, 2015
Location:
Albany, NY
#3
As previous poster alluded to, the "Mah" does not denote the physical size of the battery.