MacBook Pro 2018 battery drains when connect to an external monitor

Your MacBook Pro 15-in features Dual Graphics. An external display is wired to the Discrete graphics chip, which is more responsive and more power hungry.

Use of a "legacy"display interface such as HDMI compounds the problem, because HDMI contains the "heartbeat" refresh used by CRT displays, so the entire screen data is being pulled from the (fast & hot) display RAM and rasterized very 60th second. Use of a modern DisplayPort display would drop the "heartbeat" refresh and allow the link to go quiet when the picture stops changing, and would run somewhat cooler.

If you have an external display, it is almost always plugged in. Plug in your computer as well.

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Ditto. This is ridiculous. A Pro user probably uses dual displays from time to time - Apple!

Finally dropped 3K for my shiny new 2018 MBP ready to retire the tried and true 2012 MBP.

I use my MBP for development so I carry it into work everyday. My 2012 MBP lasted around 8 hours everyday on battery with dual monitors.

Apple engineers this amazing slim portable form factor for the 2018 MBP! Bought a slim case to carry it around with me ! Well, that’s useless when I’m stuck lugging around dongles and a charging brick everywhere I go.

The 15” 2018 MBPs (w/2.6 Ghz i7 ) battery is draining in under 2 hours while connected to external displays! The slim form factor means NOTHING if the battery is garbage and the user is forced to lug around dongles and battery bricks with them everywhere . My old 17” DEL Inspiron 9300 holds a charge longer than the 15” 2018 MBP! Completely unsatisfactory and now instead of selling my 2012 MBP like I planned I’m about to switch back before I buy the Surface Pro Laptop. That’s right, Apple’s innefeciencies and choices to ignore problems rather than create solutions has me switching back to a 6 year old MacBook Pro.

To Apple:

Fix your product!!

ChaseBenfield--

Apple is not here. Apple Support Communities is a User-to-User support forum.

There are no standard mechanisms for escalating problems to Apple support from here, and Apple support does NOT monitor these forums looking for trends and outstanding issues.

Product Feedback - Apple

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All the ranting aside, I did some testing:

MBP2018 (2,2 GHz, 32GB, Radeon 555X); battery with 17 cycles is at 97% design capacity:

• 70 minutes connected to 4K TV via HDMI drained battery from 49% to 8%, i.e. expected battery life just under 3 hours

(conditions: wi-fi and bluetooth turned off, keyboard backlight off, screen brightness on 40%, Dropbox etc. off, the only program running was PowerPoint and most of the time it was just showing the same slide; in other words, this is the ultimate maximum you can squeeze out of MBP2018)

• 70 minutes connected to low-res projector via VGA drained battery from 99% to 74%, i.e. expected battery life close to 5 hours

(conditions: wi-fi turned off, bluetooth connected to iPhone, keyboard backlight off, screen brightness on 40%, Dropbox etc. off, the only program running was Keynote; this is close to the maximum you can squeeze out of MBP2018)

There was, however one difference between the two 'scenarios': I have a 3rd party HDMI dongle and an Apple VGA dongle (dongle, dongle, dongle). Can anybody replicate the 4K HDMI scenario with Apple dongle?

I have this exact problem. If I start the day with a full 100% charge, then I plug a USB-C to Mini-DP for an external 24", I get "maybe" 2 hours of battery life until I need to plug it in. Definitely seems like there could be some firmware tweaking Apple could do to not run the discrete GPU so high on the power consumption. It's ridiculous.

From what I've found, no other issue is contributing to this. This issue is simply a result of an external display being connected and the MBP switching to High Performance Graphics mode. I've tested this with a full charge, no apps except Finder open, and the laptop sitting idle. An hour later (no external display) battery was still at 99%. Plugged in the external display, came back an hour later to 42% remaining. Odd. The only setting that I've found is to disable the automatic graphics switching, but that just disables the low-power graphics altogether, and ONLY runs the high performance graphics card. Fail.

VGA display or projector is a certifiable antique.

When you buy a modern display, one with DisplayPort input will run cooler, and a display with USB-C output will charge and run your MacBook Pro from the power supply in the display..

‘VGA display or projector is a certifiable antique.’

I agree. However, I teach at 2 different universities and it’s not realistic for me to equip 2 universities with new projectors. In addition I travel to conferences where up to nowadays approximately 4 out of 5 projectors available to me are VGA. Anyway, the answer to each and every of Apple’s problem cannot be “change the world”. Yes, it worked out for Jobs with iPhone, iPad and HTML but those days are - unfortunately- yesteryear.

Is there anyone that can test Apple’s HDMI dongle, that would be very helpful.

On the contrary: Apple IS HERE! At least long enough to remove my post saying it was ranting. They'll probably remove this one as well.

While what you say is strictly true, of the about 700,000 folks who work for Apple worldwide, the Apple employees who are Hosts of the forums settle squabbles and enforce the forum Terms of Use -- they do not make decisions about the features of products, and have no formal mechanisms to escalate problems from here to Engineering.

So perhaps it would be more correct to say "Apple Engineering and Marketing representatives are not here".

1) What is a “modern display”?

I ask because I bought 2 brand new displays off New Egg and they DO NOT have usb c out. My 2012 MBP has no problems using them without draining the battery. My 2018 MBP kills the battery. Funny thing is I can replace the battery in my 2012 MBP, but I can not in my 2018 MBP.

2) Laptops are built for portability. Professionals (Pro Users) carry their laptops with them to work. Most Enterprises are not using USB-C. Professionals can’t just tell their Organization that it needs to buy new equipment to meet their specific use case.

Is Apples solution buy another dongle or cables that Enterprise doesn’t have? If the answer is yes, than the stack of dongles and cables you lug around take up much more space than a competitive laptop that will not require the adapters and cables. So effectively for most Pro Users the slim form factor means absolutely nothing. For a normal user it’s satisfactory, but a normal user doesn’t need a MBP.

If Apple listened to their consumers before they where faced with a lawsuit forcing them to address problems it would be great because this isn’t something that is impossible or even very difficult to patch. Apple shouldn’t have rolled out a product with these problems.

No one who answers queries here is an Apple employee. All are Volunteers

I try to help users come up with some solutions that might help them, if possible. I try to help them think about their problems in different ways. I do not wish to engage in pi**ing contests.

If your 2012 MacBook is so much better, then please, by all means use it!

Now your problem is solved.

I have done some additional testing so I can provide some concrete numbers.

Testing environment: new MBP15" 2018 (i7, Radeon Pro 555X) with maximum battery-saving-settings: Wi-Fi off, Bluetooth on (for presentation remote), screen at ½ brightness, all programs off (including background stuff like Dropbox) except for Keynote running a static presentation (90% of idle time, i.e. showing the same slide).

Power draw was measured with "Coconut battery".

Power draw without external display is 3,83W with on-board Intel graphics and 11,21W when manually switched to dedicated Radeon graphics.

Thunderbolt (DVI) - MBP using 27” iMac2011 as a secondary display via Apple Thunderbolt 2 cable + Apple Thunderbolt 2 to Thunderbolt 3 dongle.

Power draw 23,55W, battery usage 22% per hour: MBP15 battery life approx. 4,5 hrs.

VGA - MBP15 using 37” 720p LG TV as a secondary screen via VGA cable + Apple VGA to Thunderbolt 3 dongle.

Power draw 20,47W, battery usage 23,5% per hour (38% in 98 min), MBP15 battery life approx. 4,25 hrs.

HDMI 720p - MBP15 using 37” 720p LG TV as a secondary screen via HDMI cable + generic HDMI to Thunderbolt 3 dongle.

Power draw 19,56W, battery usage 24.5% per hour (21% in 51 min), MBP15 battery life approx. 4 hrs.

HDMI 4K UHD - MBP15 using 65” UHD 4K TCL TV as a secondary screen via HDMI cable + generic HDMI to Thunderbolt 3 dongle.

Power draw unknown, Battery usage 35% per hour (41% in 70 min), MBP15 Battery life approx. 3 hrs.

The above results testify that the amount of energy drained depends less on the type of connection (VGA, HDMI, DVI/Thunderbolt) as it does on the type of the display it is driving. 4K UHD HDMI was twice as power hungry as 720p.

Best case scenario for using brand new fully charged MBP2018 for a presentation (lots of talking and just a few slides; every imaginable power saving option enabled) with typical projector (HDMI or VGA, up to 1080p HD) will give you up to 4,25 hrs of autonomy. In my experience more realistic scenario (Wi-Fi enabled, screen brightness at 75%, presentation with normal amount of slides) will give you about 3,5 hrs. When driving 4K UHD TV, MBP's autonomy is drastically reduced: 3 hrs is the maximum, realistic scenario is closer to 2 hrs. If you are playing a movie, even less so. Choose your movie wisely, or better, look for a power outlet before you start the presentation.

Why is this so and can anything be done about it?

From the above I draw the following conclusions. Using any sort of externel display with Thunderbolt MBP drains significant amount of battery. Idle computer draws at least 500% more energy with external display. This is regardless of the technology used, thus debunking the hypothesis that DVI/Thunderbolt is superior in situations with static images since in theory it only refreshes when needed.

The fact that any MBP's with dedicated graphic card automaticaly switches to it when connected to any type of external display is half of the problem. Idle MBP2018 draws 292% more energy (about 8W) when the dedicated Radeon graphic card is manually switched on. This means that should Apple in some future upgrade enable driving external displays from the embedded graphics it could make a noticeable improvement.

The other half of the battery drain is, it would seem, down to the Thunderbolt technology. A Thunderbolt dongle is not just a cable. In order to be able to handle all sorts of trafic (video, audio, data, power) it employs 2 controler chips, one at the entry point and the second at exit. It would seem that driving these two controllers for video draws about 10W from a MBP regardless of what's hooked to the dongle.

To sum up, a modern MBP used as presentation notebook is average at best. I have no doubts that Thunderbolt-ish technology is the way of the future but to MBP owners of today it brings dongles (which we knew when we bought the MBP) and apparently shorter battery life (which, at least to me, came as surprise). If giving presentations is the most important part of what you are using your notebook for (and are unwilling or unable to look at non-Apple products) look in the direction of MacBook Air or even an iPad. My veteran iPad Air2 with battery health at around 85% will deliver about 5 hrs of lively Keynote presentations via Apple Lightning to VGA dongle, so about 140% of what my brand new MBP is capable of.

The above results testify that the amount of energy drained depends less on the type of connection (VGA, HDMI, DVI/Thunderbolt) as it does on the type of the display it is driving.

"legacy" displays from the set: {VGA, HDMI, Single-link DVI, Dual-Link DVI} all require a high-powered adapter/dongle in addition to the power used by the Discrete graphics chip.

DVI is on no way equivalent to ThunderBolt. The term DVI/ThunderBolt is meaningless. ThunderBolt is ThunderBolt, no relation to 'legacy" DVI.

DisplayPort can be directly derived from ThunderBolt PORTS on a computer, but NOT from a ThunderBolt-3 to ThunderBolt-2 cable/adapter. DisplayPort family, in either Mini DisplayPort or Full-size DisplayPort form factor, are more efficient and less power hungry.

The fact that any MBP's with dedicated graphic card automaticaly switches to it when connected to any type of external display is half of the problem. Idle MBP2018 draws 292% more energy (about 8W) when the dedicated Radeon graphic card is manually switched on. This means that should Apple in some future upgrade enable driving external displays from the embedded graphics it could make a noticeable improvement.

Everyone on this thread is complaining about the 15-in MacBook Pro (that features Dual Graphics to improve high-end graphics functions such as Movie editing in Real-Time).

There already is a MacBook Pro that drives external displays from Integrated graphics. It is the MacBook Pro 13-in model of any computer similar to the one you are complaining about.

Executive summary:

It appears to me that you may have purchased TOO MUCH computer for the job that was most important to you, and are suffering the consequences in unwanted battery power consumption. You would be better served by a 13-in MacBook Pro, available now.

MBP 13" has much smaller battery (MBP13 = 58W, MBP15 = 83.6W) and it will not run longer under these conditions (I cannot do exact testing but I have been using my wife's MBP13-2017 for presentations on several occasions so I do speak from experience). MBA might though, as I have indicated (based on my experience with MBA2012 That I was using for presentations until recently) And also, MBP 13" has 13" screen which for many, myself included, is just to small for 10 hour days.

Not that it bears any importance for this technical thread, but when I am not teaching=presenting I do research which includes, but is not limited to, processing LiDAR point clouds with billions of points, simultaneously running several Parallels VM's for GIS analysis, or processing 3D-SfM jobs that run up to several days (anything that takes longer than a weekend is sent to the cloud computing).

SAPIENTI SAT.

You appear to have wildly different requirements for computing and presenting.

MacBook Pro is a very lightweight computer that runs on batteries. It is "all tuned up" for specific uses.

You may need a different computer for each use.