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07-30-2019

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Re: T480 battery discharge problem: internal battery goes first at all times!

2019-07-30, 16:35 PM

 

Hello everybody,

 

I had the same issue, battery 1 discharging first.

 

 

The solution for me was to reset the laptop with a pin in the small emergency reset hole.

Got the answer from this topic:

https://forums.lenovo.com/t5/ThinkPad-T400-T500-and-newer-T/Battery-issues-about-my-t470/td-p/3825442/page/3

 

Best

Edit: It worked until I restarted the computer, it is quite annoying Lenovo please fix this, it makes no sense..

 

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21 Posts

11-05-2018

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Re: T480 battery discharge problem: internal battery goes first at all times!

2019-07-31, 16:14 PM

I tried to reset the laptop (thorugh the 'reset hole'), but this has not changed anything - the internal battery still drains first. 

 

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2 Posts

07-30-2019

CH

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Re: T480 battery discharge problem: internal battery goes first at all times!

2019-07-31, 16:24 PM

I think we are screwed, it seems Lenovo sees it as a "feature".. (I remember a thread where someone from Lenovo said there were no plans to "fix" it, I will post the thread if I find it again)

I have no hope, this feature was the most important for me when purchasing a T480.

I may not buy anything else from Lenovo in the future since they are unable to provide any service on such an issue.

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294 Posts

10-28-2016

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Re: T480 battery discharge problem: internal battery goes first at all times!

2019-07-31, 16:29 PM

Earlier in this thread (I think) there was a comment that the discharge algorythm selects the battery with the lesser number of discharge cycles to use "first".  There may be more to the algoryhm than just that but:

 

I had a problem with my removable battery ( labeled battery #2 on my system) and it was replaced under warranty after about 10 months use, so compared with the new/replacement battery the original internal battery has considerably more cycles on it.

And what I'm seeing is that battery #2 the new/removable battery is always selected for discharge first.

 

Which makes ME happy ... but doen't really solve the problem for the average user.

 

If my post helps a Kudo is appreciated, if I answer your question, please mark it ”Accepted Solution“ and give it a Kudo! ... Some years ago I worked for IBM. Currently I do not work for, nor do I speak for Lenovo or IBM.
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21 Posts

11-05-2018

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Re: T480 battery discharge problem: internal battery goes first at all times!

2019-07-31, 16:38 PM

My internal battery has gone through 30 recharging cycles, while the external one has gone through 14 recharging cycles. Thus, the external battery should start draining first, which is not the case. 

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Re: T480 battery discharge problem: internal battery goes first at all times!

2019-07-31, 17:09 PM

I really don't know ... but I do think there is more to the algorythm...

with my original setup the internal battery did have more cycles on it ...

because it was ALWAYS the first to be discharged ...

 

so ... it may be the case that the order is only "flipped" if some threshold difference of discharge cycles is reached between the two batteries? 

 

My internal battery had ~150 discharge cycles and when I put in the new 2nd battery it of course had zero discharge cycles,

so maybe that was what got the system's "attention"  ... agian, I'm just speculating

 

The only hard data I have is what happened to my machine when I installed the new #2 batttery....
I'll try and dig out the old battery and do an experiment to see what happens if I put it back in........

 

 

If my post helps a Kudo is appreciated, if I answer your question, please mark it ”Accepted Solution“ and give it a Kudo! ... Some years ago I worked for IBM. Currently I do not work for, nor do I speak for Lenovo or IBM.
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294 Posts

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Re: T480 battery discharge problem: internal battery goes first at all times!

2019-07-31, 17:36 PM

Ok ... I found my original battery.

 

For reference my internal (#1) battery has 157 cycles

The new external  (#2) battery has 21 cycles

The OLD external  (#2) battery has 128  cycles

 

I have the charge threshold set at 80% for both batteries.

I put the old external/#2 battery back in the laptop and let it charge up to 80%

then unplugged the machine .......... and it started discharging the external/#2 battery

 

So ... I have no clue what the **bleep** is going on...........

other than that I'm sticking to my story that the wear leveling algorythm has more to it than just cycle count...

 

 

 

If my post helps a Kudo is appreciated, if I answer your question, please mark it ”Accepted Solution“ and give it a Kudo! ... Some years ago I worked for IBM. Currently I do not work for, nor do I speak for Lenovo or IBM.
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294 Posts

10-28-2016

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Re: T480 battery discharge problem: internal battery goes first at all times!

2019-07-31, 17:43 PM

If someone else has access to a "new"  (low cycle count) external battery ...

It would be interesting to see if temporarlily inserting it into an "older" cycle count machine would flip the discharge order

even when the old external battery is re-installed...

If my post helps a Kudo is appreciated, if I answer your question, please mark it ”Accepted Solution“ and give it a Kudo! ... Some years ago I worked for IBM. Currently I do not work for, nor do I speak for Lenovo or IBM.
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89 Posts

11-04-2013

CA

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Re: T480 battery discharge problem: internal battery goes first at all times!

2019-07-31, 18:11 PM

Remember the system chooses which battery to discharge first based on wear level rather than on cycle count. This is according to a lenovo rep. So if the internal battery has less wear than the external battery, then the internal will discharge first. The purpose for this is that cycle count does not always determine the wear level of a battery.

 

You can determine the wear level by dividing the full charge capacity by the design capaicty. For example:

 

Internal Battery

  • 24.02 - Design Capacity
  • 22.80 - Full charge capacity
  • 22.8/24.02=0.9492 

 

External Battery

  • Design Capacity - 24.05
  • Full charge capacity - 22.93
  • 22.93/24.05=0.9534

Based on the above data, the external battery has less wear because it holds a closer charge to its original designed capacity. Therefore in this scenario the external battery will discharge first. Once the external battery starts to show more wear than the internal battery, the system will opt to discharge the internal battery first. The purpose of this design is so that each battery wears evenly over time.

 

While I understand the rationale, I'd much rather have choice to decide how my system discharges the batteries.

ThinkPad T480 | i7-8650u | 32GB | MX150 | WQHD | 72wh
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Re: T480 battery discharge problem: internal battery goes first at all times!

2019-07-31, 18:31 PM

 

Souldier - thanks I did not know that ... or  ... i forgot i knew that   ;-)

 

 

So my #1/internal is:  24.02  /  18.54

New #2                         24.09 / 23.94

Old #2                          24.05  / 20.29

 

 

So I would have thought that BEFORE I replaced the #2 battery the algorythm would have selected my original #2 to discharge first since it clearly has less wear on it ... but on my machine batt.  #1  was still being discharged first ..............

 

If my post helps a Kudo is appreciated, if I answer your question, please mark it ”Accepted Solution“ and give it a Kudo! ... Some years ago I worked for IBM. Currently I do not work for, nor do I speak for Lenovo or IBM.
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