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Old March 3rd 17, 05:49 AM posted to alt.comp.os.windows-10,alt.comp.os.windows-8,alt.windows7.general
Ken Springer[_2_]
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Posts: 3,817
Default How to interpret laptop battery results.

On 3/2/17 6:12 PM, Paul wrote:
Ken Springer wrote:
On 3/2/17 10:01 AM, Arnie Goetchius wrote:
Ken Springer wrote:
On 3/1/17 8:19 PM, Paul wrote:
Ken Springer wrote:
Let's say you run the powercfg command from the command line.

The battery design is 60,000, but the last full charge is 40,000.

Would it be accurate to say the battery has 66% or 2/3rds of it's life
left? Or is some type of sliding scale more accurate, and maybe the
battery has only 40% of it's life left?

Is there an easy to understand web site for this? I'm not sure of
what
terms I should search for in this instance.

The term you want is "battery fuel gauge".

http://batteryuniversity.com/learn/a...ery_fuel_gauge

The connector on the laptop battery has room for serial connections,
allowing the CPU to query the battery IC.

The battery capacity declines with age. When Windows says "100% full",
it means 100% of the remaining 60% or original capacity the old
battery has.
You check the "hours and minutes remaining", as a means of
guesstimating
the Watt-hours the battery actually holds. If you laptop used to say
"three
hours" when the battery had just finished charging, maybe now it says
"two hours", under equivalent conditions. Of course, controlling the
conditions on a laptop is notoriously difficult.

Some fuel gauges, if they have not received a calibration cycle,
they count the number of times the battery have been charged,
and estimate the loss in capacity as a result. I'm sure the driver
software in Windows, cleans up any "inconsistent" information
so you won't get a scare like "105% full".

The battery IC is supposed to be "counting coulombs" or some such.
It does that, rather than using open circuit battery voltage
as some sort of indicator. Coulombs should be a better method,
than any voltage-based method.

Hi, Paul,

That's not the type of indicator I was referring to. I'm referring
to the
powercfg report available with Windows.

Open a command window.

Navigate to Windows\system32.

Type powercfg -energy -output power.html

It takes a minute or so for a report, power.html, to be created in
the system32
folder. You can use the full pathnames as you desire to end up with
the output
file where you would like it as well as change the name of the report.

Open the file in whatever, search for Battery Information. Those are
the
numbers I'm interested in.


The above is for Windows 7. I've read online that for 8 and 10, you
change
energy to batteryinformation. I don't have access to an 8 or 10
laptop, so
cannot confirm this.
I ran the "battery" option and got the following:

NAME DELL 7XFJJ4B
MANUFACTURER Sanyo
SERIAL NUMBER 8050
CHEMISTRY LION
DESIGN CAPACITY 73,260 mWh
FULL CHARGE CAPACITY 68,964 mWh
CYCLE COUNT -

Is that what you are looking for?


Looking for it? Nah, I found it. LOL

I'm looking for a way to interpret those numbers in "layman's terms".
How do I explain how much battery "life" is left when the battery is
used, such as in a used laptop I want to sell.

Can I say something like the battery has 94% of its expected life left?
Some kind of description/explanation the average person on the street
would understand.


http://www.techrepublic.com/article/...will-tell-you/

DESIGN CAPACITY mWh when it was new
FULL CHARGE CAPACITY mWh it holds when 100% now

That article has a bit more info.


It looks like batteryreport provides more info that the version in W7.
I'll have to compare the reports when I get a chance.

I do the command line to put the report on my desktop, so it's easy to
drag and drop to where it will be permanently stored in a cloud application.

But I'm still a bit perplexed as to how to accurately, and simply,
explain to someone the current status of a used battery. Maybe I could
say something like "The battery has X% of it's design life left."

A couple months ago I did some research on how to maximize the life of
your battery.
I created a single page doc on taking care of your laptop battery. Main
points are as follows:

Simple ways to make your battery last longer...
1. Do not charge your battery to 100%. Heat is the enemy of battery
life, and charging to full charge creates internal heat in the battery,
which shortens the life of the battery.
2. Do not fully discharge your battery by letting it die.
3. Try to keep your battery charged to between 40%-70%.
4. Try to keep your battery at room temperature. So don’t leave your
computer in a hot or cold car, for example.
5. If your AC adapter (charger) fails, ensure the replacement charger
matches or exceeds the specifications of the original charger. Also see
if you can determine if the charger you are buying includes some safety
circuits, such as a temperature sensor that shuts the charger down in
case the charger gets too hot. That will prevent the charger itself from
failing.

--
Ken
Mac OS X 10.11.6
Firefox 51.0.1 (64 bit)
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"My brain is like lightning, a quick flash
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