# 2016 MBP Battery Convert mAh to Watt hours

Discussion in 'MacBook Pro' started by jrbd90, Dec 24, 2016.

1. ### jrbd90 macrumors newbie

Joined:
Jul 1, 2009
#1
Ok, so the 2016 is supposed to have a 76 watt hour battery

System information and coconut battery list battery life and design capacity in mAh.
System information under battery power also lists the voltage as 12.8V.

Design capacity from coconut battery for my 2016 15" battery = 6669mAh.

Formula is (mAh)*(V)/1000 = (Wh). For example, if I have a 6669mAh battery rated at 12.8V, the power is 6669mAh * 12.8V / 1000 = 85Wh.

Even if it was calculated at 12v the watt hours would still be over 80.

To get ~76watt hours the design capacity would need to be closer to 6000mAh.

What are the rest of you showing for design capacity in Coconut Battery?

2. ### protoxx macrumors 6502a

Joined:
Oct 10, 2013
#2
watts=amps * volts

Example 120 watts= 1amp * 120volts

amps=watts/volts

?amps= 76 watts / 12.8 volts

5.9375 amps=76 watts/12.8 volts

5.9375 amps=5937.5 milliamps

Lots of batteries are advertised at some milliamps but at a unrealistic voltage.

That's how electric circuits perform. Batteries may perform in a different or non-linear fashion. The batteries are a chemical storage mechanism.

3. ### littlepud macrumors regular

Joined:
Sep 16, 2012
#3
The battery is nominally rated at 11.4V and 6667mAh. It's stamped right onto the battery itself.

https://d3nevzfk7ii3be.cloudfront.net/igi/y2nrVjxllI32cO3r (via iFixit)

4. ### jrbd90 thread starter macrumors newbie

Joined:
Jul 1, 2009
#4
Thanks that makes more sense. I wonder why it states 12.8v under system information.
I can see capacity fluctuating as mine is showing 6841mAh in coconut