Before I get into this a little background. I am currently an electronic technician in the telecommunications field. I have been working with electronics for over 20 years both designing circuits and building equiment to field repair and quality control for custom cirruit and equip manufactures. I also happen to hold a US Amateur Radio License and build power supplies and battery charging circuits.
So I didn't just grab something that had the right plug and hoped it works.
Quote:
Originally Posted by Robertb
Dear kdf:
This is a huge misconception. People think that all USB chargers are the same. They are not. Many of them run at far different amps and voltages.
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Like I stated in my post I have load tested this charger and it puts out a very stable 5 vdc with a min amount of ac induce ripple and is rated for 550ma or aprox 1/2 amp. The supplied battery witch is a 3.7v 1000mAh battery should not be charged at a rate of more than C/5 witch in this case would be 200ma. The USB standard also happens to be 550ma max current draw so the reader should by design not draw more current than that at any time or risk the possibility of damage to your computer if the current drain on the 5V Vbus is grater than that.
Quote:
Originally Posted by Robertb
WHY on earth try using a charger from a cell phone when we give you one made for the device in the box? You may have damaged the battery or the device. And you may be nullifying the warranty.
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The other reason that I have done this is that I have not load tested the transformer unit that was supplied with the reader. I have had problems with burning up equipment with unknown wall warts like this one before. I also did not want to use it until I had had a chance to see if it produced RFI (radio frequency interference). The last USB wall wart I used wiped out a good portion of the 20meter amateur radio band and I wanted to be able to read while listening for contacts.
And this is why this battery meter is driving me nuts....