[SOLVED] Possibly a bad battery for Thinkpad T400?

[irets]

Hi,
I noticed that on my Lenovo Thinkpad T400 the

[irets]

I noticed they sell T400 replacement batteries on laptopbatteryexpress.com but they'd charge $430.15 total for shipping the $78.90 battery to my country.
That is insane.

[NeddySeagoon]

Irets,

Do you care what

[irets]

Neddy,

This is my only travel laptop that I own so having even a somewhat 'decent' battery life is a plus.
Of course I always have a charger with me also.

I ended up ordering a Green Cell 4400mAh battery for my T400 from a certain online store in my country.
Other reviewers had not had issues with it but I am aware of the risk I am taking by not using an official Lenovo battery.

I think it's impossible to find 'new' official Lenovo batteries for laptops old as this, so second-hand is the best I can do, unless if I look into disassembling the battery myself and refurbishing it, which I do not feel comfortable doing right.

I'll update this thread and report back when I get my battery, if my apartment does not catch on flames and/or I get hospitalized.


EDIT:
Now that I look a the current battery which is in my laptop, I do not see any Lenovo markings.
It's a TradeShop 4400mAh battery. Could the previous owner of this machine have replaced the original battery with this? Or could Lenovo have had a partnership with TradeShop back when they rolled out his machine to the store shelves in 2000s?

[sdauth]

This is not a good idea to let it drain to zero. I killed my old T400 battery this way (although it was still showing 76% capacity)
On my T400, I always shut it down (if power source is not available) when it reaches 20%. My current no name battery is almost two years old and shows 94% capacity (around 5 hours with low luminosity, non intensive load)

[irets]

Sdauth,

Five hours of non intensive load is pretty good. Do you know the mAh capacity on yours?
Are you using any power management software?

Long ago, I remember reading somewhere that letting a rechargeable battery drain to the point where the device powers off is better than having a constant charge on the cells.
Was that bogus information?

[sdauth]

[szatox]

[NeddySeagoon]

sdauth,

It addition to what szatox said, a deep discharge and recharge to 'full' does nothing for the battery.
It only recalibrates the battery charge management system.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

[sdauth]

NeddySeagoon,

This mean the battery cell could actually still be ok ? The only thing I know is that I'm unable to charge it anymore after having it let it drain to zero. (fast orange led blinking)
So maybe a bug in the battery firmware ?
Unless there is way to manually reset the battery charge management system (eeprom) ? I don't know of such tool.
EDIT : Found this : https://www.youtube.com/watch?v=6_J_yuI1xMo although it is not cheap.

[logrusx]

[szatox]

An error in BMS doesn't automatically mean the cells are dead though. It could be a response to e.g. undervoltage or a bug or whatever.
This said, bear in mind that Li-ion cells are quite dangerous. The electrolyte is highly flammable, lithium is somewhat explosive, the whole thing should be considered toxic... And they can be set of by short-circuit or overvoltage, not only physical damage.
If you want to salvage some parts, better give this task to someone who knows what he's doing.

[irets]

[logrusx]

[irets]

Thanks for the explanation.

[NeddySeagoon]

Irets,

The battery management software estimates the remaining charge by measuring charge in an change out over time and comparing that with battery capacity.
Its dead reckoning so errors mount over time.

The deep discharge lets the battery management software get a foot on the ground again by defining zero. (Empty)
The next charge calibrates the amount of charge that the battery can hold, in your case 57% of its rated capacity when new.
Laptop batteries are rated end of life when they can only store 50% of the rated capacity.

Lithium batteries loose capacity with every charge/discharge cycle. Its a feature of the chemistry/construction.

Lithium spontaneously ignites on exposure to water vapour, so a damaged lithium cell is very dangerous. Water vapour is everywhere.
Once the fire starts, its very difficult to extinguish. Water just makes it worse.

Your battery is close to end of life. A good quality replacement is the only option - or no battery at all.
Recycle the old battery properly, so that its dismantled safely.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

[irets]

Neddy,

Thank you for the in-depth explanation.
I never knew this stuff about laptop batteries.

So, I got my GreenCell battery today in mail and it came with the following instructions:

1. Insert batter into laptop/tablet and turn it on without AC adapter connected.
2. Use the battery until system alerts low battery level (usually 5-10%).
3. Do not let the battery discharge completely, it may cause irreversible cells' damage.
4.Connect the AC adapter and charge battery according to the device's instructions.
5. After 3-5 complete charging cycles, the battery should reach it's maximum capacity.

Good and all... but my battery arrived with such a low charge my T400 could not completely power on, so there likely already is some damage done to the cells.
I'll charge it up completely, let it drop to ~15% and charge up again a few times and see what cat /sys/class/power_supply/BAT0/capacity reports.
The locking lever is also a bit different on this battery compared to my previous one, but it works just as good.

[irets]

The problem was with my previous battery.
I now have much longer battery life and /sys/class/power_supply/BAT0/capacity isn't limited to 57.

Thank you to everyone who shared their Li-ion wisdom in this thread. Marking as solved.