Application to display battery info

First of all, I am not sure the title of this question is the most appropriate however this is what I meant to say,

There are many ways to extend the life of a laptop battery. One way is by not connecting it to the AC adapter all the time which will overcharge it. I read that in this website.

1. Is there an application which automatically prevents the charging of the battery once it has reached 80% charged? I mean that is such a cool feature. Sometimes people tend to forget to remove the AC adapter and this could diminish the capacity and reduce the life time of the battery.

2. Does the battery indicator in ubuntu display info or pop-up when the battery is almost dead (dead not in the sense of usage time) but rather a degraded battery?

Solution 1:

Wow, that web site is COMPLETELY WRONG. I am an engineer and among other things, sometimes design and build battery packs. I have read many data sheets from battery manufacturers and they all say the exact opposite, and I have experimental evidence that they are correct.

Batteries LIKE being fully charged. If the charger is overcharging them, then it is broken. A correct charger stops charging the battery when it is full, so it is good to leave it plugged in if you can. The more often you discharge the battery, and the deeper you do so shorten its life. A typical battery can handle several thousand cycles if you limit depth of discharge to 30% ( meaning you recharge it once it falls to 70% ). Going to 50% cuts the life of a typical battery down to the 1000 cycle range, and 30% or less drops it to a few hundred. A battery that is fully discharged and remains that way for weeks or months will loose much of its capacity if it can be recharged at all.

Notice the inverse relationship between depth of discharge and state of charge. Battery manufacturers and engineers use the former term. The marketing guy who wrote that web site probably did not understand the difference and so he got it upside down.

Solution 2:

I don't agree with the answer. Keep battery always 100% charged is NOT suggested.

For Li-Ion rechargeable battery (almost all laptop use li-Ion battery) , most manufacturers suggest to keep them in a cool and dry condition with 40%~50% capacity, no matter for camera battery or laptop battery. Why? Because this is the best conditon for battery storage. I have several evidences to support my opinion:

1) My Thinkpad X31 laptop with battery always full charged and dead in around 3 years later. Only 10% capacity left.

2) My Thinkpad T400 laptop has a battery with good condition after 3 years usage (more than 85% capacity left), by limitting the threshold to 30%~80%. I never overcharge or deep discharge the battery, it will reduce the lifespan of battery significantly.

3) I have several 18650 size Lion Sanyo batteries, which is the material of laptop battery, when they were shipped to me, the voltage are all around 3.78V (around 40% of it's capacity), while the full charged voltage is 4.20V. It means in factory, they are charged only to 40% capacity, for storage reason.

I saved them for around 2.5 years in refrigerator (so it's always cool), and the voltage of them still keeps around 3.76V~3.77V.

Solution 3:

• You can get some additional information, apart from right clicking the battery icon next to the clock (get's shown when you pull out your power chord), by opening a Terminal and typing

  cat /proc/acpi/battery/BAT1/*
  

• Does the battery indicator in ubuntu display info or pop-up when the battery is almost dead (dead not in the sense of usage time) but rather a degraded battery?

  Yes it does:

  
  (something like that)

Solution 4:

OMG, The top answer is wrong and it is very convincing since its first paragraph.

However, when it comes to "Batteries LIKE being fully charged", it is clear that there is some miXunderstanding between Li-ion and other batteries (Ni-based and lead-acid).

Ni-based and lead-acid car batteries "LIKE being fully charged" but Li-ion "DO NOT".

It is already correct that Li-ion LIKEs being in 30%-80% level of charge due to Li-ion cell deterioration beyond the range.

However, the answer were already right about depth of discharge i.e. the less discharge the more life cycle.

I used to have the same conclusion as the top answer when I first read that top search-result How to Prolong Lithium-based Batteries page and remembered only the part about depth of discharge. Years after I got to read it again and was so dazzled how could I missed to remember such critical part so I did search for Li-ion cell deterioration and found a research paper so I was certain it was true about 30-80% myth.