Quote:
Originally Posted by jusmee
Dave, did you notice there are three wires on the PP battery. That may mean it is a 'smart' battery, which means it certainly should be capable of being more precise.
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Yes, it definitely is a "Smart Battery", but does not mean that the charge indicator is capable of being more precise than what you are seeing. The charge state circuit is mass produced in the millions, as are the battery cells, and then they are joined together at the final manufacturing steps. During use, the charge state chip learns the batteries full charge voltage and it's empty voltage and a few voltages along the way, and probably not very much else. It would certainly be possible to add more RAM and ROM memory to the monitor microcontroller in the battery so that very precise charge/discharge curves for the battery could be kept. But, why? The levels that it does store are sufficient to do the job and keep costs down, and the battery is going to change over time and temperature anyway.
Quote:
Originally Posted by jusmee
This means it shouldn't vary so much with 'specific batteries' as the smarts are specific to the battery, and they also monitor temperature and load and from some reports I have seen in software that interrogates these smarts, they even account for historical performance. All in all, I believe we should expect better than what we are getting.
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What you say is quite true, but the specific controller in the battery used in the PocketPRO does not have the fourth temperature sensing lead. In more critical applications the historic performance is also monitored, but a book reader is far from a critical application, and the simple controller used in the PocketPRO's smart battery is sufficient for it's intended function. I do not think that berating Astak for low resolution battery power indication is a valid criticism, when almost all cell phones (a tremendously larger market) only show battery state to 4 or 5 bars resolution. In most (all ?) of those cases, only a very rudimentary calibration of the non-linearity of the charge/discharge voltage curve is attempted because that is all that is really necessary for simple mass produced appliances.