Vostro 1400 battery overcharging?

I just replaced a Vostro 1400 battery after it
started flashing a yellow code, showing no charge
in the battery meter.

The new one charges up okay, but the Vostro seems
to keep trickle charging it (occasional blue flash
on the battery light) and the power meter doesn't
show idle status, though it shows 100% charge.

I'm wondering if this is a failure that took out
the old battery, and so this battery will soon
fail as well if overcharging is what took the old
one out.

Is there a way to prompt the battery charger to
lay off?

Otherwise it becomes a science experiment, leading
to maybe don't put any battery in at all.

The machine is up on AC power 24/7 for years at a
time.
--


On the internet, nobody knows you're a jerk.

On Fri, 04 Nov 2016 15:07:30 -0500, Ron Hardin
wrote:

I just replaced a Vostro 1400 battery after it
started flashing a yellow code, showing no charge
in the battery meter.

The new one charges up okay, but the Vostro seems
to keep trickle charging it (occasional blue flash
on the battery light) and the power meter doesn't
show idle status, though it shows 100% charge.

I'm wondering if this is a failure that took out
the old battery, and so this battery will soon
fail as well if overcharging is what took the old
one out.

Is there a way to prompt the battery charger to
lay off?

Otherwise it becomes a science experiment, leading
to maybe don't put any battery in at all.

The machine is up on AC power 24/7 for years at a
time.

Don't know what the charger is assuming. Is that a genuine or
after-market replacement battery? How often is the blue light "tick"?

My V1400 was behaving very nicely until one day whilst charging after
a bit of battery operation. I was monitoring the indicated SOC % and
it went 25 .... 30 ... 2 and then lights came on.

Ran the deep diagnostics - which are a crock - and concluded it was
the battery pack. Split it open and found one (parallelled) pair of
cells to have SFA capacity. As a test, replaced them with an old pair
from a project and verified that the charging behavious was "as per
the book".

I haven't bothered to get a replacment pack as this machine is now
about 4th in line and effectively mothballed.

pedro wrote:

Don't know what the charger is assuming. Is that a genuine or
after-market replacement battery? How often is the blue light "tick"?

My V1400 was behaving very nicely until one day whilst charging after
a bit of battery operation. I was monitoring the indicated SOC % and
it went 25 .... 30 ... 2 and then lights came on.

Ran the deep diagnostics - which are a crock - and concluded it was
the battery pack. Split it open and found one (parallelled) pair of
cells to have SFA capacity. As a test, replaced them with an old pair
from a project and verified that the charging behavious was "as per
the book".

I haven't bothered to get a replacment pack as this machine is now
about 4th in line and effectively mothballed.

It's one of the $70 batteries not one of the $13 ones, and has a 2 year
guarantee, so presumably is done right. The cheap ones fail by having no
capacity

And it gets the charge amount right 100%, and seems to have about 3:30 hours
capacity under a test.

Maybe the charger is waiting for a temperature verification before putting the
charger on absolute idle. Once a battery is full, charging goes into heat.

The slight confirming evidence is that the original one failed, perhaps driven to
death by this same thing. We'll see what happens.
--


On the internet, nobody knows you're a jerk.

On Mon, 07 Nov 2016 06:05:25 -0500, Ron Hardin
wrote:

Maybe the charger is waiting for a temperature verification before putting the
charger on absolute idle. Once a battery is full, charging goes into heat.

That's not how Li-xx chargers operate. (I have designed a
commercially successful Li-Ion charger.) They are current-limited
constant voltage chargers. For 18650 cells - found in the vast
majority of laptops - we used 1A as the current limit. When the
volatge reaches the set-point, usually 4v2, the current will taper off
and when it reached a predetermined level (10% is typical) the charger
effectively disconnects. You can see this sometimes where the
displayed % charge will reach 100%, then slowly drift down to 95% or
so. The voltage droop will cause the charger to return to charging,
and the cycle repeats. When operating the machine on AC these cycles
will be quite long - many minutes - as there is no drain on the pack.

The slight confirming evidence is that the original one failed, perhaps driven to
death by this same thing. We'll see what happens.

As above, there should be NO "trickle charge" on any Lithium
recharging.

pedro wrote:

On Mon, 07 Nov 2016 06:05:25 -0500, Ron Hardin
wrote:

Maybe the charger is waiting for a temperature verification before putting the
charger on absolute idle. Once a battery is full, charging goes into heat.

That's not how Li-xx chargers operate. (I have designed a
commercially successful Li-Ion charger.) They are current-limited
constant voltage chargers. For 18650 cells - found in the vast
majority of laptops - we used 1A as the current limit. When the
volatge reaches the set-point, usually 4v2, the current will taper off
and when it reached a predetermined level (10% is typical) the charger
effectively disconnects. You can see this sometimes where the
displayed % charge will reach 100%, then slowly drift down to 95% or
so. The voltage droop will cause the charger to return to charging,
and the cycle repeats. When operating the machine on AC these cycles
will be quite long - many minutes - as there is no drain on the pack.

The slight confirming evidence is that the original one failed, perhaps driven to
death by this same thing. We'll see what happens.

As above, there should be NO "trickle charge" on any Lithium
recharging.

Dell laptops won't start charging again no matter how low the battery voltage gets. That's
actually a problem if you run them for months at a time on AC power. You have to disconnect the AC
to wake up the charger.

It's that not-disconnected state that I think it's in, but it's a flash every ten seconds from the
charger, which apparently indicates the charger is still on but not seriously on.

Constant voltage probably means the current is minimal in any case, then.

It turns into a science experiment. Either it kills the battery or it doesn't.
--


On the internet, nobody knows you're a jerk.

On Tue, 08 Nov 2016 09:34:34 -0500, Ron Hardin
wrote:

Dell laptops won't start charging again no matter how low the battery voltage gets.

I've never left this one on AC for more than a day or two at a time,
so hadn't observed that. I muast admit it surprises me.

That's actually a problem if you run them for months at a time on AC power.
You have to disconnect the AC to wake up the charger.

I twould present a problem.

It's that not-disconnected state that I think it's in, but it's a flash every ten seconds from the
charger, which apparently indicates the charger is still on but not seriously on.

Constant voltage probably means the current is minimal in any case, then.

It turns into a science experiment. Either it kills the battery or it doesn't.

The "coulomb efficiency" of Li-Ion on charge is very high. Our
testing placed it between 98.5 and 99%. That means that only 1-1.5%
of the current into the cell is generating heat, whereas the actual
charging chemical change is either neutral or *very slightly*
endothermic, so cell heating (while charge current is being accepted)
is non-existent for all reasonable purposes.

If the charge IS cut off when "full charge" (sic) is reached, then the
only harm that could follow from a non-recycling charging system would
be low voltage cutoff. The main battery sustains *some* load by
virtue of maintaining the CMOS battery as well as some internal power
control circuitry, and eventually this - plus the minute
self-discharge - will drag it down to the cutoff point for the pack.
The pack protection module should prevent any further external drain,
so the pack is effectively isolated. The prospects of it killing the
battery are minimal in that scenario.

I had one pack here date-coded last millennium, from an Acer model
which came with a choice of chemistry. Two otherwise identical
models, one with NiMH and the other a Li-Ion - probably their first
venture intothat area. Until I junked then a few years ago, the NiMH
had gone to battery heaven but the Li-Ion, which I would try and pull
out to recharge annually, would still deliver over an hour's running
and showed no signs of age or off-charge deterioration other than
reduced capacity.