Soldered Battery

[Firethorn]

You get the voltage mostly right and you're good.  IE 3.7/3.6 Volts don't matter.  Given the description of how long it lasts on a charge, it's not pulling any tricks like 'draw so much amperage that the voltage drops' such that a bigger battery wouldn't be overwhelmed and push too much voltage through.

[230RN]

Firethorn remarked,

And, as KD surmised, their battery management system is 'extensive'.  Their batteries, for example, are actively water cooled(using the AC system if necessary!), and the car will report that it's batteries are fully charged, and stop charging, when the charge gets to around 90% of the cell's actual charge capability, because that last 10% of charge represents about 90% of the wear from charging.

I didn't know about that 90%.  It explains some curious but casual observations (limited to NiCads and Pb gel-cells) I've noted over the years.  Thanks for that tidbit !

Is that "90%" generally true of all types of chemistry, or just for the ones you're talking about?

As it happens, I run my laptop* as a desktop off its wall wart with the battery removed most of the time.  I re-install it from time to time when I go portable.  Maybe I'm inadvertently doing a "good thing" for that battery pack --that is, not keeping it topped off 100% of the time?

Terry

* HP G-72... don't know what type of cells are in the battery pack.

[Firethorn]

That really depends on the battery management.  You might be doing it a real disservice, or a service.

Depending on the maker of the laptop, there may be a utility available that will stop the charging at 80-90%.  It'll cost you run time if the power goes out or you otherwise have to unplug, but only for about the first 6 months to a year.  After that, lowered battery wear will mean that the 80% of a reduced wear battery is more capacity than the 100% of the more worn one.

I know it's not unique to Lithium Ion.

At least for standard lead-acid cells keeping it at 100% is the recommended level, NiCd and NiMH suffer more from fast charging than being fully charged, though I have heard of people not fully charging them to help preserve them.  With them it's more avoiding fast charging.