[ale] OT: Charging smart phones

[Chris Fowler]

Anyone here putz with trying to figure out charging current of their 
phone?  I have a HTC Thunderbolt and I've been trying to figure out how 
to get it to charge the fastest.

I purchased a 3" USB A -> micro cable off eBay to use in my car so that 
I can keep the phone in the console for WAZE.  I got tired of coiling up 
a cable.  I purchased a 12v -> 5v USB converter off eBay.  This is in a 
sealed enclosure and can provide 5V up to 3A.  With the short cable and 
that device my TB will charge at almost 800mAh.  I then switched to a 
cable that is 3' and came with 'HTC' wall chargers I got off eBay.  The 
phone drops to above 100mAh.  With the cable A I get 'AC Plugged'.  With 
cable B I get 'USB Plugged'.

I have read up on USB DCP and what had to be implemented in Minty boost. 
  I have not checked the USB output of this device to see if I have 2.8v 
on D- and 2.0v on D+.  It could be that I do, but the thin gauge wire in 
the longer cable could be forcing the TB to think it is attached to a PC.

I would like to make a small 5V to USB adapter that will take any 5V 
input and make the device think it is a charging device.  Need 75K 
resistors and 49.9k ones.  Anyone have any? Anyone mess with the USB DCP 
to charge their devices?

Chris