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- Booting laptop problem
August 22, 2014, 2:46 pm
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If a laptop battery fails for whatever reason, should it still be able
to switch on / boot / be usable powered on just the mains power, with or
without the battery pack installed?
I have a friend who when booted to Windows it claimed there was a fault
with the battery. They are not technologically minded. Taking the
battery out, and they claim the laptop won't boot, is this right?
Brand is a Toshiba.
Re: Booting laptop problem
I run my Acer all the time, without the main battery pack inserted.
I only use the main battery pack, when going outdoors with it.
If you have the model number of the laptop available,
there may be a PDF for it online. My Acer manual didn't
mention operation without the main pack, but I tried it anyway.
And it worked. A unit which needs the battery pack, may
state that in the manual.
Like everything in life, there can be exceptions. Perhaps a 15 year
old laptop with nickel cadmium battery pack, would need the pack to
be present. The more modern the unit, the more likely it can run
without the main pack present.
For a fair test, unplug the adapter from the wall, and
give the battery-less laptop a chance to start from zero power.
That's in case a safety circuit latched in the off state, and
is waiting for your to cycle the mains power (Off, then On again).
The CR2032 coin cell can also play a part in this puzzle. If
both the main battery pack is bad, and the CR2032 needs replacement,
that could prevent it from starting. For unexplained reasons,
a percentage of motherboard designs, do not tolerate completely
flat (zero volt) CR2032 batteries, and they will not start with
them present. It would be a coincidence, for both the CR2032
to die, in the same week as the main pack.
Laptop CR2032's are shrink-wrapped, to hide the spot welds
of the cable to the battery surface. You buy a replacement
that is similarly wrapped and cabled. A computer store
may be able to help with this, as I don't know whether
Radio Shack would stock these. The cell voltage should be
above 3V when new, and no less than 2.4V or so when
just about worn out. A multimeter can be used to check.
(Probe with needle point probes, inside the two pin
connector on the end.) Such batteries will drop from 2.4V to
0.0V, in about a month or so of maintaining clock time and
settings. That's how long it takes the battery to
completely fail, when it is worn out.
In the picture, the 0326 could refer to the battery
being made in the year 2003 week 26. Be careful to avoid
stock which is this old :-) The shelf life of a CR2032
is around ten years or so. And if you're lucky, a date
stamp may be on the label. I wouldn't have had to
mention this, except I went to a battery store in
the mall, and was sold a set of flat coin batteries
(retail packaging and everything). From a battery store...
Never had a problem with Radio Shack that way. For any
kind of battery, even replacement main pack batteries, you
want to buy them from someone who sells a lot of them,
and is known to have "fresh stock".
Re: Booting laptop problem
Some laptops won't start if the battery is physically absent.
Similarly, I've seen desktops that won't start if the CMOS battery was
removed, even if it was a dead (too low) battery.
Put the battery back in. Boot and look at Power Options. Make sure
there isn't a setting for battery operation alone.
Have you unplugged all external devices (USB keyboards, mice, printers,
memory drives, etc) from the laptop and then see if the laptop powers up
and boots okay with the battery absent? Perhaps your A/C adapter is too
weak (by design or defect) so it cannot provide all the power needed by
both the laptop and all those external devices. Although the battery
might be weak (doesn't last as long as a new one), it still may supply
sufficient power during the current surge when powering on. After the
surge on power on, the A/C adapter might be sufficient for the running
Some folks are overly physically abusive, and laptops get banged around
a lot more than desktop PCs. The A/C cord might've gotten whacked many
times when used while travelling or even at work or home simply by
shoving it around so the power connector going into the laptop gets hits
repeatedly. This could break the receptable in the laptop so the
connection is flaky. While it sounds goofy, putting the battery in
could have you moving the power cord in a way that lets it make a good
connection while removing it happened to push the power cord so it then
had a bad connection. With the battery removed and the power cord
plugged into the laptop, turn on the laptop and wiggle the power cord.
I've seen users note that when inserting a non-Toshiba battery that
their laptop would not start. Their problem is the laptop would not
boot on the battery alone but required booting on A/C power. After the
boot completed and they were in Windows, they could remove A/C power and
continue on the battery. Seems there is some logic in the Toshiba to
determine if a Toshiba battery is installed, or it could be the
protection circuitry to prevent lithium temperature runaway that causes
fires. The logic board in the battery is missing when the battery is
missing so the laptop doesn't know if it cannot read the logic from the
battery or if the logic is wrong or the battery is missing (there is no
physical presence detection of the battery). Lithium batteries contain
their own logic to prevent thermal runaway
); however, from the
experience of these users, there also seems to be some recognition of
whose battery is in the laptop. If the battery is absent, recognition
is also absent.
I've seen reports that some Toshiba and HP laptops won't boot without a
battery. Looks like they expect to detect the presence of a battery and
that it's the right type of battery. Could be that if it detect an
overly low voltage that it refuses to boot since the normal state would
be to charge the battery while on A/C power, but charging a bad lion
battery could cause a fire, and a missing battery would register as
undervolted (i.e., zero volts). There are probably many reasons why
laptop makers won't permit their products to power on if they cannot a
battery and its condition. Looks like you'll have to leave a battery in
the laptop, even if it's an old one so you can leave a new replacement
somewhere else in a safe place.
Re: Booting laptop problem
I would think any safety built into the laptop's power management
circuity would be totally independent of the conditions of the CPU, or
memory, or video card, or hard drives, or any other subsystem. Why
would you want to protect against thermal runaway only when the CPU was
While it would be nice if hardware never failed, why couldn't a laptop
check for undervoltage in case the inbuilt thermal runaway circuit
inside the battery was non-functional? I've not seen redundancy in the
logic used for the circuit inside the battery. The only reason why
redundancy wouldn't be built into the laptop is the cost for it (which
is perhaps the volume cost of 1 chip and a couple extra foils on the
mobo in the laptop).
Actually I'm wondering if firmware, even if just an ID or signature,
within the battery along with ID logic within the laptop is permitting
recognition, so a missing battery is seen as a mismatched battery. This
would be similar to why refilled ink cartridges fail to function. The
printer sees an ID reused and considers the cartridge still empty. I've
heard of the tricks to fool the printer, like cycling through 3
cartridges or covering some of the contacts on the cartridge before
inserting it, but you get the idea. Something in the battery could be
used to ID it to the laptop as a viable power source. With an absent
battery, there's no ID info.
Why would Toshiba-branded battery packs allow the laptop to startup but
a non-Toshiba battery cause the laptop to not start? Both LIon
batteries would have the internal thermal runaway protection so
something else differs between them. A voltmeter or even a load tester
won't show differences in new Toshiba and non-Toshiba battery packs.
Like with presentation data passed during USB handshaking to identify
the device, perhaps something similar is used for battery ID.