Sorry I'M not Mike, but this is Piclist, and here is my advice.

If you charge your battery, measure the energy you put in.
In your system, measure the energy sucked away from the battery,
then discharge completely your battery; don't forget
to measure it's expiration energy.

Then compute the lossssss.
A perfect battery has no loss, nobody's perfect.
Watch the loss !

Here i want to cite the appropriate song for the circumstance.
"You can watch them die... Live on T.V. "

This song is from "The BOX"

Batteries are good for human beeing, given them a reasonable retiremnt
time
before they pass away.

Jean Mercier



Now you know what you have

Scott Walsh wrote:
>
>      Battery performance information is extremely hard to get hold of. We
>      are making a product at the moment that needs to incorporate both a
>      battery charger and a mechansim for determining the amount of useable
>      time left in a battery ... the battery people are of little help, this
>      includes comapnies such as Gold Peak, Panasonic, Energizer and Varta!
>
>      Hence, I have had to spend a large amount of time using GPIB
>      controlled DVM's to measure batteries while being charged and
>      discharegd.
>
>      Mike, what method did you use for the product to give a user an
>      indication that the battery was failing? ... I have been playing with
>      usign either an absolute measure or rate of change of the battery
>      voltage.
>
>      kind regards,
>      SW.
>
>      PS. I think this thread is great, it is easy to tell from the tone
>      that people are writing in that there is a mutual appreciation of the
>      headache these 'simple' devices cause. But hey .. its only software
>      8-)
>
> ______________________________ Reply Separator
 _________________________________
> Subject: Re: Batteries [OT]
> Author:  wwl@netcomuk.co.uk at INTERNET
> Date:    21/11/97 09:36
>
> >Manufacturers don't say much about the capacity of alkaline batteries, I
> >think a safe assumption would be about 4x the capacity of the same size
> >Ni-Cd.  But not rechargeable, or rechargeable only a small number of
> >times.  This is the least expensive battery system to manufacture, since
> >the user pays someone else for the batteries.
> I recently needed detailed discharge curve info on alkalines, and was
> staggered to find that Duracell couldn't supply anything othr than a
> couple of reference curves at specific loads & temps. Surely these guys
> have been making batteries long enough to be able to supply a simple
> program which would give a discharge curve at any given load & temp
> (i.e. what the customer really NEEDS) - apparently not! We had to spend
> a lot of time testing, as we had to provide a lo-bat warning with a
> specific amount of running time available (due to the standards the
> product had to comply with). Lack of info was a REAL pain.
>      ____                                                           ____
>    _/ L_/  Mike Harrison / White Wing Logic / wwl@netcomuk.co.uk  _/ L_/
>  _/ W_/  Hardware & Software design / PCB Design / Consultancy  _/ W_/
> /_W_/  Industrial / Computer Peripherals / Hazardous Area      /_W_/