
Watt time is left - ingve
http://www.tedunangst.com/flak/post/watt-time-is-left
======
dexwiz
Apple should have added a Amp or Watt usage number, not removed the estimate.
Similarly, most new cars have fuel estimates on their dashboards. But its not
just miles to empty, its also miles per gallon. So drivers can get feedback on
usage rates versus total capacity.

I imagine the argument about this, is that most people don't have any handle
on what a Watt or mAh is. But people don't have a good handle on how far 25
miles is, or how much a gallon is in comparison to their tank. Think about it,
you rarely see the fuel you put into your car beyond a few drips at the pump.
And while you may know that its 25 miles between your house in work, if I took
a random point on a map and said find something 25 miles away, with no scale,
most people couldn't do it. Gallons and MPG are just arbitrary numbers that
consumers have learned how to compare. If you exposed those numbers, they
would get a better handling on what their device consumes, and how their
activities affect it.

~~~
bryanlarsen
They still have the percentage indicator, which is presumably directly
proportional to mAh remaining, and people generally have a good understanding
of what percentage is.

Using your analogy, your gas gauge doesn't show the number of gallons, it
shows a relative level.

~~~
dmeola
My car tells me how many miles I have left by basing its estimation on my
consumption over the past 30 miles. It has been pretty accurate.

~~~
eridius
I think you can liken the situation with macOS to switching from a gas car to
a Hybrid. Gas cars have relatively predictable MPG. Hybrids don't. Your Hybrid
can go from 25MPG up to 100+MPG depending on the way you drive, and it can
bounce back and forth between the two constantly during a trip. Now, I have to
admit, I don't own a car at all and so I don't know if hybrid cars actually
try to estimate mileage remaining, but if they do, then surely their estimate
will change wildly as you change how you drive (e.g. smooth highway driving to
traffic jam to city driving to aggressive driving to defensive driving, etc).

~~~
wl
I own a Prius. Fuel efficiency doesn't seem to be any more variable than the
conventional cars I've driven. The distance remaining estimate seems
reasonably accurate in that it goes down ~50 miles after I've driven 50 miles.

~~~
eridius
Whenever I drive a Prius with ZipCar, the MPG numbers change wildly while I
drive, and even the average MPG can change by 5–10 miles over the course of a
decent drive. I assume the distance remaining estimate is based on that
average MPG number, but since I have seen it change by significant amounts,
that means the distance remaining estimate certainly is reasonably inaccurate.

If you always drive your car in the same manner then sure, you'll probably
have a reasonable estimate. But similarly if all you do with your computer is
browse the web, you'll also have a predictable battery remaining estimate. But
while many people do drive fairly consistently, your usage of your computer
probably has a lot more variety in terms of energy impact.

------
imwally
I started working on a little CLI battery status indicator even before I knew
Apple was going to pull the time remaining feature. On macOS I like to hide
the dock and menu bar but usually keep terminal open with tmux running so I
decided to write something I could place in my tmux status line where I could
keep an eye on my battery life.

[https://github.com/imwally/battstat](https://github.com/imwally/battstat)

~~~
lloeki
I've had a python{2,3} script for, like, years, collecting advanced details
using _ioreg_.

Sample output:

    
    
        ~> ~/Workspace/toolbelt/battery 
        Temperature = 2967
        CycleCount = 384
        DesignCapacity = 6600
        MaxCapacity = 6362
        WearRatio = 96%
        CurrentCapacity = 5886
        ChargeRatio = 92%
        Voltage = 12162
        Amperage = -1061
        InstantAmperage = 64286
        InstantTimeToEmpty = 8:34
        TimeRemaining = 5:33
        AvgTimeToEmpty = 5:33
        FullToEmptyTime = 5:59
    

[https://github.com/lloeki/toolbelt/blob/master/battery](https://github.com/lloeki/toolbelt/blob/master/battery)

~~~
serkanyersen
This is awesome. Thanks

------
tedmiston
I haven't upgraded to 10.12 yet, but this seems like a good time to remind
people about coconutBattery [1].

You can't see a prediction in minutes yet (maybe they'll add one with Apple
removing it), but the battery metrics have always been more useful than for me
than what's built-in. You can see the discharge rate, current charge, full
capacity, and original capacity though.

[1]: [http://www.coconut-flavour.com/coconutbattery/](http://www.coconut-
flavour.com/coconutbattery/)

~~~
dchest
Thank you! It has "time until empty" indicator (%r)
[http://imgur.com/a/74qLJ](http://imgur.com/a/74qLJ)

~~~
tedmiston
Oh, cool. I hadn't seen the menu bar option before.

------
jsnell
If the core problem is supposed to be that power usage is now more erratic,
how about this small refinement:

\- Compute discharge rates for one minute segments, like Ted did in this post

\- Store the last 10 discharge rates

\- Report a time estimate based on the minimum/median/maximum of those 10
rates.

That gives fairly quick feedback after you start doing something expensive,
but isolates the effect of short-lived and infrequent bursts.

~~~
mikeash
It's not as if erratic power usage is a new thing, anyway. My 2013 MPB's
battery life can easily vary by an order of magnitude. It'll last 10+ hours if
it's sitting there not doing much, or maybe an hour with an intense 3D game.
The estimate they provided up to 10.12.1 was still quite good if I was doing
the same thing for a while, which I usually am.

------
Osiris
I wrote a battery meter (BatteryBar) 8 years ago that uses a more complex
algorithm to calculate an "average time remaining" rather than instantaneous.
Basically, my software keeps track of how long the battery has lasted in the
past and uses that to inform the current time remaining (with adjustments
based on current discharge rates, etc).

I'm not sure why Microsoft/Apple haven't done something similar. I've even
sold licenses to Surface Pro sales reps that they use to show off the battery
life of the Surface to potential enterprise clients.

------
staticelf
Is there a background for this? I don't understand the article.

~~~
aneeshnl
Apple removes the ‘time remaining’ battery estimate in new macOS update

[http://www.theverge.com/2016/12/13/13939278/apple-macos-
sier...](http://www.theverge.com/2016/12/13/13939278/apple-macos-sierra-new-
macbook-pros-battery-life)

~~~
Etheryte
Well that's simply the silliest way to try and solve the battery-life issues
of the new laptops.

~~~
tptacek
That's not what they're doing. They're recognizing that the estimate has
always been misleading.

~~~
mikeash
Quite an amazing coincidence that they recognized this _right_ after they
released a new line of computers whose battery life failed to live up to
expectations.

And quite annoying that they're "recognizing" this, when it's often quite
useful and not at all misleading. I made good use of that display before, and
now they've taken it away.

~~~
coldtea
> _Quite an amazing coincidence that they recognized this right after they
> released a new line of computers whose battery life failed to live up to
> expectations._

Or was reported to have "failed to live up to expectations", by idiots who
merely assumed the estimate and didn't bother to do an actual clock wall
check.

~~~
mikeash
So I'm being punished for the actions of some idiots I never met? That's not
better.

~~~
coldtea
No, I doubt they changed it to punish Mike Ash specifically.

Rather they decided to cut the fake precision (X hours YY minutes) and stick
to the segmented-battery icon display.

It's like some statistics were saying there's a 45.32% chance of something,
just because that's what their simplistic division of the samples gives them,
despite the confidence margin being plus/minus 5 percentage points.

Instead, they now tell you it's "between 40% and 50%".

The target audience of the statistics is not "punished because some idiots
took 45.32% literally". They are just shown a better value.

~~~
dpark
More correct but less useful isn't actually better. An estimate of time
remaining is more meaningful than a percentage of battery capacity remaining,
even if the latter can be provided with more accuracy.

~~~
coldtea
> _More correct but less useful isn 't actually better._

I'd argue that more correct is by definition more useful.

~~~
dpark
Correct but inactionable is useless. It's basically undeniably correct that
our universe will eventually die of entropic heat death. This isn't useful,
though.

Projections about Earth's global warming are undoubtedly less correct but far
more useful because they are actionable.

Correctness is _not_ synonymous with usefulness.

------
johansch
So is there any good (hopefully free/open) third-party solution to bring it
back to the menu bar on the mac?

~~~
akvadrako
Sure, iStat Menus is great.

~~~
jdcarter
Seconded on iStat Menus. Despite its cost, it shows a _ton_ of useful
statistics, including moving graphs of CPU activity, network IO, storage IO,
etc.. It's easy to customize the display so you see just what you care about.

------
andrewgleave
Years ago (probably 2009) I wrote a small utility which polls the SMC to get
current and voltage readings and from hardware. Wrapped it up in a simple app
which shows realtime power consumption in my menu bar.

Didn't do much with it since the SMC keys differ for pretty much every piece
of hardware Apple create and there is practically no information so it
requires some investigation for each.

------
tedmiston
Can anyone on the latest update of macOS confirm whether the time prediction
is also gone from Activity Monitor > Energy at the bottom?

~~~
yoz-y
The estimate is still there, you can also get if by running `pmset -g batt`.

------
onion2k
I don't think it's fair to suggest Apple removed the battery life indicator
because they don't know how to make one.

~~~
mikeash
It's a joke. Of course they know how to make one. They had one in 10.12.1.

------
trymas
> sysctl -A | ag watt

Gives nothing. Why it's not shown? rMBP late 2013, macOS 10.12.2.

~~~
ggreer
The author is using a Thinkpad running OpenBSD. I don't think macos or linux
kernels expose battery info as kernel state.

Also, thanks for using ag. :)

~~~
trymas
> I don't think macos or linux kernels expose battery info as kernel state.

Bummer.

> Also, thanks for using ag. :)

Thank you for making it ;)

------
Skunkleton
They removed it to cut down on complaints. Most people wont get the advertised
10 hours, and now most people wont notice.

~~~
comex
Or:

Most people will get the advertised 10 hours, and now people won't think
they're not because of an inaccurate estimate.

~~~
Skunkleton
I guess it depends. Seems like people are getting more that 10 hours out of it
when used for light tasks.

------
waynecochran
197.45836985100788781720 is grossly superfluous precision is it not?

------
abritinthebay
The point is that those estimates aren't actually accurate. That they mislead
the end user so they don't belong in primary UI.

This article is nice to show that you can get the data from the command line
(you can still get it elsewhere in macOS too) but the snark at Apple for
saying they _can 't_ do it when it's in fact a deliberate design choice just
makes the author look uninformed & petty.

~~~
wyager
It doesn't matter if they aren't perfectly accurate. Neither is the battery
"percentage"; it's a constructed number that usually has an unintuitive
relationship with the actual physical state of the battery. The point is that
it's a useful number, as it answers the question "approximately how much
longer can I keep doing what I'm doing right now?".

~~~
abritinthebay
Percentage is pretty darn accurate actually. Mostly because it's based on
remaining charge not fluctuations in load like time.

You can measure this yourself with any lipoly batteries you have at home. It's
quite reliable

~~~
0xcde4c3db
Percentage is a dynamically constructed estimate too. It's more accurate
because the underlying variables tend to change more slowly and predictably,
but the actual charge levels corresponding to "0%" and "100%" aren't fixed,
and the calculations do sometimes drift noticeably from reality.

~~~
mikeash
Incidentally, this is why you'll sometimes see an improvement in battery life
if you do a full discharge. It's not that it's good for the battery itself
(quite the opposite, in fact), but it gives the estimator a better view of how
the battery is behaving, so it can better estimate the charge level at any
given point.

