Advice on maximising lifetime (charge cycles) of laptop battery

In article , Paul
wrote:

When you have a single cell, like my digital camera
does, you can run those down to 0 volts.

which digital camera might that be and what battery chemistry is this
mystery single cell?

regardless, that's a bad idea.

nospam wrote:
In article , Paul
wrote:

When you have a single cell, like my digital camera
does, you can run those down to 0 volts.

which digital camera might that be and what battery chemistry is this
mystery single cell?

regardless, that's a bad idea.

The (provided) charger sets the policy.

I checked the cell voltage before plugging the
thing in to be charged. And it was right at zero
volts on the multimeter. It charged up just fine.
And that's probably the battery I took the picture
with a couple hours ago.

The camera is a Canon Powershot.

Paul

Paul wrote:

John Doe wrote:

One familiar warning is to avoid discharging lithium to zero, in
dumb devices.

That's NOT all I know... THE REST OF WHAT I KNOW WAS SNIPPED.

This is true for battery packs with multiple cells. If you have a
14.4V battery pack, it could be using multiple cells, and running
those down to zero is not allowed. (As the charger checks, and if
it detects a low voltage, it won't inject current.)

When you have a single cell, like my digital camera does, you can
run those down to 0 volts.

The reason you can do that, is there is no danger of a single cell
"reverse biasing itself". Whereas if you have a battery pack with
multiple cells then "N-1" cells can strong-arm the "weak" cell and
place it under reverse bias, and cause it to plate out metal.

I think you are talking about nickel metal hydride (NiMH) or
earlier. I read an article about that concerning NiMH. The reason
lithium cannot be run down to zero is different and also applies to
single cell lithium.

One other consideration with respect to single versus multiple
cells... A single cell can be partially charged without worrying
about leveling that might take place near the end of the charge.
That is clear, because there is only one cell and no need to even
the voltage between multiple cells. That is, if you can guess there
is only one cell in your device.

Paul wrote:
nospam wrote:
In article , Paul
wrote:

When you have a single cell, like my digital camera
does, you can run those down to 0 volts.

which digital camera might that be and what battery chemistry is this
mystery single cell?

regardless, that's a bad idea.

The (provided) charger sets the policy.

I checked the cell voltage before plugging the
thing in to be charged. And it was right at zero
volts on the multimeter. It charged up just fine.
And that's probably the battery I took the picture
with a couple hours ago.

The camera is a Canon Powershot.

Paul

The battery type is Canon NB-11L.

This is as close as I'm going to get to a datasheet.
This is a third party replacement for it.

http://www.produktinfo.conrad.com/da...NON_NB_11L.pdf

system: Lithium-Ion-Battery
nominal voltage: 3.7V
end charge voltage: 4.2V

capacity after standard charge
nominal: 600mAh

The chemistry could be Lithium-Cobalt or Lithium-Manganese.

http://batteryuniversity.com/index.p..._with_voltages

Paul

In article , Paul
wrote:

When you have a single cell, like my digital camera
does, you can run those down to 0 volts.

which digital camera might that be and what battery chemistry is this
mystery single cell?

regardless, that's a bad idea.

The (provided) charger sets the policy.

it determines the charge strategy, not the minimum cutoff voltage.

I checked the cell voltage before plugging the
thing in to be charged. And it was right at zero
volts on the multimeter. It charged up just fine.
And that's probably the battery I took the picture
with a couple hours ago.

then you did something wrong, or the battery is reporting 0v for some
reason despite it not actually being 0v internally.

li-ion batteries have multiple connectors to communicate to the device
the charge level and sometimes other info, such as number of cycles,
health status, etc.

it's possible you used the wrong two pins, or the voltage is 0v unless
the battery thinks it's actually in a camera (or other compatible
device).

The camera is a Canon Powershot.

i was about to ask which powershot and which battery but you answered
that, at least for the battery.

In article , Paul
wrote:
The battery type is Canon NB-11L.

that's a lithium ion battery pack, thus the 'l' in its name.

lithium ion batteries have protection circuitry and *cannot* be
discharged to 0v. they are considered fully discharged at around 3v.

lower than that risks being unable to charge it at all, and if it's
actually 0v, it's completely *dead* and cannot be recharged anymore.

the protection circuitry also prevents overcharging, as bad things can
happen.

This is as close as I'm going to get to a datasheet.

canon has some info:
https://shop.usa.canon.com/shop/en/catalog/battery-pack-nb-11lh

This is a third party replacement for it.

avoid, unless it's a well established battery vendor (i.e., not noname
**** off ebay).

aftermarket batteries tend to not be as reliable or as safe and
frequently do not have the claimed capacity. if anything bad happens,
canon will blame the battery (and rightly so).

the better aftermarket batteries aren't that much cheaper than canon's
own, so it's not worth it.

nospam wrote:
In article , Paul
wrote:

When you have a single cell, like my digital camera
does, you can run those down to 0 volts.
which digital camera might that be and what battery chemistry is this
mystery single cell?

regardless, that's a bad idea.
The (provided) charger sets the policy.

it determines the charge strategy, not the minimum cutoff voltage.

I checked the cell voltage before plugging the
thing in to be charged. And it was right at zero
volts on the multimeter. It charged up just fine.
And that's probably the battery I took the picture
with a couple hours ago.

then you did something wrong, or the battery is reporting 0v for some
reason despite it not actually being 0v internally.

li-ion batteries have multiple connectors to communicate to the device
the charge level and sometimes other info, such as number of cycles,
health status, etc.

it's possible you used the wrong two pins, or the voltage is 0v unless
the battery thinks it's actually in a camera (or other compatible
device).

The camera is a Canon Powershot.

i was about to ask which powershot and which battery but you answered
that, at least for the battery.

In article , Paul
wrote:
The battery type is Canon NB-11L.

that's a lithium ion battery pack, thus the 'l' in its name.

lithium ion batteries have protection circuitry and *cannot* be
discharged to 0v. they are considered fully discharged at around 3v.

lower than that risks being unable to charge it at all, and if it's
actually 0v, it's completely *dead* and cannot be recharged anymore.

the protection circuitry also prevents overcharging, as bad things can
happen.

This is as close as I'm going to get to a datasheet.

canon has some info:
https://shop.usa.canon.com/shop/en/catalog/battery-pack-nb-11lh

This is a third party replacement for it.

avoid, unless it's a well established battery vendor (i.e., not noname
**** off ebay).

aftermarket batteries tend to not be as reliable or as safe and
frequently do not have the claimed capacity. if anything bad happens,
canon will blame the battery (and rightly so).

the better aftermarket batteries aren't that much cheaper than canon's
own, so it's not worth it.

I have two batteries total.

The third-party battery is in the camera now, and
has a voltage of 3.77 at the moment.

The spare battery is Canon branded, and acquired at
the same time as the third-party battery.

The battery has three terminals. The outside
two terminals are marked "-" and "+" for
easy identification.

A measurement three hours ago, shows the outer two
terminals of the Canon reading zero again.

I placed the Canon battery NB-11L in the Canon charger
and 2.5 hours later or so, the "full" light came on.

Measuring the outer two terminals registered 4.12V.

Shooting about 10 minutes of video with the now-recharged
dead battery, ran the battery down to around 3.93V or so.

So it does appear the battery was dead (again), and is
charged up (again). For how long, who knows.

Paul

On June 24, I wrote:
[...]

In addition to Paul's response - which covers most of the issues -,
you might want to read the thread "charging to 80 or 90%" of March 16 in
comp.mobile.android.

That thread is about phones/tablets, but they use the same battery
technology, so most is also applicable to laptops. The thread is only
122 articles, so an easy read! :-)

Addendum: The "charging to 80 or 90%" also partly discusses laptop
batteries and how to keep them charged between X and Y%.

Posts in that thread mention that some brands have brand-specific
power manager' software which allows the battery to be kept between X
and Y%, or at least below Y%.

A poster (Libor 'Poutnik') advises:

quote

For laptops, try Google ( replace .. by actual values )

"your vendor your model battery charge manager"
or
"your vendor your model power manager"

or like that.

/quote

In article news describe that - and how - it should be possible to write general - non
brand-specific - software to keep the charge between X and Y%, but I was
and am not aware that such software actually exists.

NY, which brand, model, etc..is your current laptop? (AFAIK, you
didn't mention it and have not responded since your OP.)

In article , Paul
wrote:

I have two batteries total.

The third-party battery is in the camera now, and
has a voltage of 3.77 at the moment.

The spare battery is Canon branded, and acquired at
the same time as the third-party battery.

The battery has three terminals. The outside
two terminals are marked "-" and "+" for
easy identification.

that's good. not all batteries have that.

some have several pins, often unmarked:
https://i.ebayimg.com/images/g/fgQAAOSwHnFViMeW/s-l1600.jpg

A measurement three hours ago, shows the outer two
terminals of the Canon reading zero again.

that's because the protection circuitry shut it down so that the
battery can't be used anymore when it's fully discharged (around 3v),
which would cause it to discharge even further, thereby damaging it.

the battery cells are *not* 0v. the protection circuitry prevents it.

there's actually a little bit of headroom in the cutoff voltage because
the battery will continue to self-discharge.

I placed the Canon battery NB-11L in the Canon charger
and 2.5 hours later or so, the "full" light came on.

Measuring the outer two terminals registered 4.12V.

Shooting about 10 minutes of video with the now-recharged
dead battery, ran the battery down to around 3.93V or so.

So it does appear the battery was dead (again), and is
charged up (again). For how long, who knows.

it appears you don't understand batteries.

there is no way that a lithium ion battery will discharge to zero and
then be able to recharge.