x2100 battery troubles

[gevor]

Hi,

So, I ran into another issue with my x2100, this time with the battery. Basically, it was ok for 2 years and then it started discharging from 60% to 5% immediately, with two different batteries.

Now, longer version.

I got my x2100 about two years ago and bought a 9-cell and later a 6-cell battery for it, which became my main one.
6-cell (5200 mAh, all original stickers present) worked fairly well for almost two years, however about two months ago it started showing some dodgy behaviour: it took the laptop 2 hours or so to get from 100% to 60% and then it went immediately from 60% to 3%.
// Funny enough, just a few weeks before it started, the laptop was working at least 5 hours with that battery.
Over the next couple of weeks it continued to deteriorate up to the point when it started dropping from 80% to 3%.

Ok, I thought it might be a battery problem, so I decided to get a new one.

I got a new 6-cell battery last week (pretty crappy no-name, 4400 mAh, not 5200 original as advertised), it came almost full, so I plugged it in and started discharging it, cycle 0. It took two hours ot so to go from 90% to 60% and then, to my surprise, it immediately went from 60.4% to to 7.2% and in a minute to 0.7%.
When I charged it and started the second cycle, it went from 100% to 37.5% in 4.5 hours and then immediately from 37.5% to 6.8% and then in two minutes from 6.8% to 1.9%.

I am starting to think that the problem is not with the battery itself, but with the laptop / EC / ...

Have you seen such behaviour with your x2100-s? Any ideas what might have caused it, how to diagnose it and what could be done?

A few points:
* After this rapid discharge, the battery charges normally, steadily going from 0% to 100% in 2 hours or so.
* I am using the original 90W barrel charger
* powertop is showing consumption around 8-10W, and the laptop runs cool; also I did some experiments limiting the CPU frequency to 400 MHz to make sure it's not the high current / power consumption
* I am using xyte.ch's EC, which is supposed to fix battery readings. I tried generating exander's EC, with fix-ec-debug + true-battery-reading + battery-current patches it matches the one I am using now, except for the backlight bit (around 0001090 / 00010b0) if I read it correctly.
* One of my USB 3.0 ports (blue one on the left) was dead on arrival. Moreover, it is consuming -150mV!
* I bricked my ME back in 2021.

[gevor]

And one more thing.

Initially the first battery had 100% capacity:

Code: Select all

        /sys/class/power_supply/BAT0/charge_full_design             =   5484 [mAh]
        /sys/class/power_supply/BAT0/charge_full                    =   5484 [mAh]
        Capacity                                                    =  100.0 [%]

In a week or so it started showing 98% capacity, and it remained so for almost a year:

Code: Select all

        /sys/class/power_supply/BAT0/charge_full_design             =   5484 [mAh]
        /sys/class/power_supply/BAT0/charge_full                    =   5374 [mAh]
        Capacity                                                    =   98.0 [%]

Then, suddernly, it changed to 88% capacity and remains so until now:

Code: Select all

        /sys/class/power_supply/BAT0/charge_full_design             =   5484 [mAh]
        /sys/class/power_supply/BAT0/charge_full                    =   4848 [mAh]
        Capacity                                                    =   88.4 [%]

[gevor]

The new battery when I plugged it in was showing 4180 mAh design and 100% capacity:

Code: Select all

        /sys/class/power_supply/BAT0/charge_full_design             =   4180 [mAh]
        /sys/class/power_supply/BAT0/charge_full                    =   4180 [mAh]

        Capacity                                                    =  100.0 [%]

Then during the first charge it managed to charge to 4400 mAh showing 105% capacity:

Code: Select all

        /sys/class/power_supply/BAT0/charge_full_design             =   4180 [mAh]
        /sys/class/power_supply/BAT0/charge_full                    =   4180 [mAh]
        /sys/class/power_supply/BAT0/charge_now                     =   4400 [mAh]

        Charge                                                      =  105.3 [%]
        Capacity                                                    =  100.0 [%]

However during the second charge (after I turned my laptop off and then back on) it started showing 94% of the original 4180 mAh capacity:

Code: Select all

        /sys/class/power_supply/BAT0/charge_full_design             =   4180 [mAh]
        /sys/class/power_supply/BAT0/charge_full                    =   3937 [mAh]
        /sys/class/power_supply/BAT0/charge_now                     =   3937 [mAh]

        Capacity                                                    =   94.2 [%]

[gevor]

Ah, and the final bit, regarding the 9-cell battery.

The laptop was discharging normally, steadily on 9-cell until it reached 6.8%. And then it was working for more than 2 hours showing 6.8% remaining, not moving at all.

Unfortunately I gave away that battery so I can't check it now, but I used it for a couple of weeks, and it always behaved like this.

[gevor]

And another bit: with the new battery it takes about 30 minutes to get from 100% charge to 99.9% charge.

But then again, it is reporting 4180 mAh battery now (not 4400 mAh) and only 94% capacity left (not 105% as it was yesterday). So I assume it might have charged it to full 4400 mAh, it just can't get the right readings.

[gevor]

And another oddity.

I was charging the battery for a while, from 44.1% to 59.4% (I was charging for 20 mins or so, after using it for four hours on battery power), then I had to go, so I closed the lid, disconnected the power adapter and packed the laptop. In a couple of hours I opened it, running on battery, and now tlp-stat was showing 100% charge! Futhermore, it took 20 minutes to get from 100% to 99.9%.

So now I am pretty sure it's not the battery itself (at least not the power elements), but either the battery controller, or EC, or something in between. Either the laptop is not fully charging the battery (while reporting full charge), or it is shutting down before fully discharging the battery (somehow I think it is less likely).

Do you have any thoughts, ideas?

[gevor]

It is getting more and more interesting.

On the fourth cycle the new battery went from 100% to 25% in about 4 hours (!), then immediately (in less than a minute) to 7.2%, then immediately (again less than a minute) to 2%. Ok, something expected after all the problems I described above.

However, to my surprise, this time it charged only to 89.4% of the left capacity. Battery is still "charging" according to tlp, but the actual percentage is not changing for the last couple of hours, and current_now is 0.

Code: Select all

/sys/class/power_supply/BAT0/charge_full_design             =   4180 [mAh]
/sys/class/power_supply/BAT0/charge_full                    =   3937 [mAh]
/sys/class/power_supply/BAT0/charge_now                     =   3521 [mAh]
/sys/class/power_supply/BAT0/current_now                    =      0 [mA]
/sys/class/power_supply/BAT0/status                         = Charging

Charge                                                      =   89.4 [%]
Capacity                                                    =   94.2 [%]

Ok, I am going to stop spamming for a while with the hope that the experts on this forum might come up with an idea of what's going on there and how to fix it.