I was disappointed that my question was not answered. I cannot see any evidence of battery cell behaviour in that linked article; I can only see assertions.
- I would have welcomed being corrected if I had failed to spot evidence in that article.
- I don’t regard their unsubstantiated assertions as useful. They do not cite their sources except for the non-specific statement, “The information is compiled from the manufacturer's specifications, test labs and crowdsourcing.”, shown on their homepage.
For my part, I am conducting testing that I hope will progress my own bank of evidence of battery behaviour.- I have no reason to believe that my results will be of use to anybody other than owners of Dell Inspiron 17 7000 Series computers.
- - My test computer is a Dell Inspiron 7779.
- - My test computer’s batteries are not made up of Type 18650 Li-ion 3.7V cells but 4.4V cells, possibly Li-Polymer cells similar to those used in my smartphones & my tablet.
- My battery cells are part of a battery and that battery’s charging & discharging behaviour is governed by a battery management system.
- Battery cell performance has been widely remarked up on and there are many scientific & empirical studies available for scrutiny.
- What I have never seen are reports of studies of complete battery systems - cells in batteries governed by the battery management systems in laptops.
- I have no idea what my battery management system is doing with regard to maximum charging voltage reached and this, I understand, is a most important factor in determining battery longevity i.e. the actual [effective] number of charge-discharge cycles achieved is determined by the maximum charging voltage reached.
I have good records of battery capacity for each of the two batteries I possess for the test computer.- I measure capacity by running PowerCfg Battery reports / Energy reports to seek out the ratio Last Full Charge / Design Capacity
- Both batteries were always charged to 100% [as shown on the Windows SysTray gauge] and external power was always left on when it was available.
- I refer to “external” power rather than “mains” or “AC” power merely because I have special-to-type 19.5V powerbanks for the test computer so I can have power available almost always.
- - Test battery 1 - 4.5 years old, used on battery power for probably over an hour a day for its first year [its capacity dropped to 80% during that period], after that it has been on external power for almost the whole time. In the following 3.5 years, it has been in use for 6 months a year and in storage for the other 6 months and its capacity has dropped by a consistent 8% a year.
- - Test battery 2 - 2.5 years old, it has been on external power for almost the whole time. It has been in use for 6 months a year and in storage for the other 6 months and its capacity has not dropped i.e. it remains at 100%.
For my tests, I have changed the computer’s charging behaviour to start charging at 80% and stop at 90%.- Selecting those particular levels was somewhat arbitrary.
- I have to temporarily allow the batteries to charge to 100% [as shown on the Windows SysTray gauge] in order to run PowerCfg Battery reports / Energy reports.
- I do not expect to be able to conclude anything for a couple of years i.e. after both batteries have had two periods in use and two periods in storage.
It was somewhat disconcerting to find, so soon after starting this test, that- Dell Tech support now say [in the video referenced earlier on in this thread] that allowing the battery to reach 100% charge every time made no difference to battery longevity.
- The OP’s newer version of Dell Power manager lite does not have my version’s facilities for limiting the charging level. I think this might also indicate that Dell no longer think it worthwhile.
Those things make me think that my results might well be that limiting the charging level has no effect. But I’ll only build up my own evidence by trying so I will continue my test.
Denis
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