On 7 April 2015 at 12:52, Bob Blick wrote: > I seem to remember if a USB phone is plugged into a computer the current > is limited to 500mA. But if the cable tells the phone it's plugged into > a dedicated charger, it might try to draw 1 Amp. > Might not work so well on all computers :) > Such capability as it may have could be replicated with an adaptor that connected at either end of a standard USB cable and which could be produced in eg China for well under $1. This could be switched as theirs is or used only when required. The latter is marginally cheaper. As noted by Bob and others, the device almost certainly changes the charging mode if the power source is designed to accommodate such a facility. "They say "charge any phone twice as fast". Limitations will include: - Chargers operating at capacity will allow no change. - Chargers operating at more than 50% capacity will allow some change but not double. - Phones with very small batteries will not be able to accommodate double charging rate as usually max rate is C/1. This will not apply to almost any "smart phone" as these tend to have at least 1000 mAh cells (batteries) and usually ~=3D 1500 mAh. C/1 rate for these is > 500 mA limit in some modes s= o will allow increased rates. - Suitably 'smart' devices will already maximise charging capability. Not quite a total "con" but certainly "economical with the truth". Good opportunity maybe for a campaign for an adaptor? :-) Russell --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .