I'd like to comment on the battery subject. This is based on my readings of several articles as well as practical research done at my work, where battery condition sometimes litterary is a life or death issue. (Battery operated respirators and defibrillators, patients risk dying if those don't have power when needed.) First: All that's stated about Li-ion batteries also hold true for the other rechargeable types. They all have a time limited life span! Then there's also a limit to how many times thay can be recharged, where li-ion batteries have plenty more cycles which makes it a nearly non issue for them. The “memory effect” is highly disputed. It’s existance seems more like an axiom than absolute truth. There are several written articles both pro and con. My own theory (not tested) is that the alledged memory effect is the result of sheer cycle numbers. If you recharge the battery every time you’ve used some of it’s capacity instead of using most of the capacity before recharging, you’ll get more cycles used within the same time frame, which in turn will reduce the available capacity. Now to battery charging and discharging... Different types of batteries have different properties when it comes to internal resistance, internal discharge and how well they handle large currents as well as deep discharges. Lead-acid batteries ar good at handling punishment in terms of large currents and deep discharge, which is a major reason for using them in cars. Li-ion batteries are at the other end of the scale, with excellence in minimum internal discharge and high capacity density. Recent development have come up with designs that allow them to handle moderately high discharge currents as well. A battery is “full” when the voltage is about 20% above the nominal, and it’s “empty” when the voltage has dropped to 20% below nominal. If the voltage drops further it’s defined as a “deep discharge”, which usually decreases the capacity more than a regular discharge and therefore should be avoided. Another way of beating a battery is by quick-charging. A regular recharge of an empty battery should take at least ten hours! Twenty hours is about the optimum charging time for most batteries. The “few minutes” recharge times found nowadays with many R/C toys is a prime example of battery torture! What worries me more is that even other appliances, like cell phones, come with quick (~4h) chargers only. Cheers Olle
Woah, I just saw a good one. A customer review for a keyboard stated that he was disappointed that the usb connected was just an extension cord. The keyboard was really a PS2 only. But his reason for being disappointed was that PS2 keyboards are 'slower' than usb. ??? Please correct me if I'm wrong. But I don't see how that could even be. I guess it's possible that there are a few micro-second differences in how the PS2 signal is handled vs. USB. But considering how slow the human brain is to reacting to things, I can't see this as being noticeable or anything to be concerned about.
As I've learned it's rather the other way around, at least for mice but I think it applies to keyboards too. PS2 is faster (more responsive) than USB! The reason is that the PS2 port is used exclusively for the input device, while USB is a one-for-all feature with lower priority. /Olle
