Re: envstat wrong: who's at fault?

[Steven Bellovin <smb%cs.columbia.edu@localhost>]

On Jul 26, 2010, at 11:59 10AM, der Mouse wrote:

> Last night, I wrote, of the issue I had with envstat/envsys values,
> 
>> One thing I have not yet done is to plot the figures to see what they
>> look like - I'm letting the battery drain to the point of the machine
>> going dead while recording this information; once that's done I'll
>> have some figures worth plotting.
> 
> I've now done this.  The pictures are interesting, and clearly indicate
> that the discharge rate fairly consistently under-reports the actual
> discharge rate (in terms of the reported charge values, that is; I have
> no independent measurements of either figure, so I can't tell which
> one, if either, correponds to the electrical reality).
> 

How old is the battery?  In my experience, as batteries age their discharge 
characteristics change markedly.  The hardware-reported value may not account 
for that properly.


                --Steve Bellovin, http://www.cs.columbia.edu/~smb