HTC Hero Forum

Fast phone charge via computer?

Was wondering if theres any way to get the fast charge that you get from the wall charger to work with a usb from computer charge. I know its "slower charge" because the computer also allows data transfer and mounting of the sd card, but maybe theres a possible way to shut that off? Also, would a double USB port cord that are used for external hard drives improve charge time at all? Two normal sized USB coming from computer to the miniUSB port on hero.



#1 LxMxFxD, Feb 15, 2010
it's a limitation of the power available in a USB port. that is done to protect some USB devices..
#2 mysticmead, Feb 15, 2010
Check out this thread:

For a more in-depth knowledge, go to this link and find the power section

USB in a NutShell - Chapter 2 - Hardware
#3 treborcj, Feb 15, 2010
OK... here's a little info on charging... the wall charger is putting out 1000ma.. or 1a.. the USB port is limited to 500ma or .5a since a battery is charged on current more than voltage a higher current charges faster. in this case.. the wall charger will charge twice as fast. since the stock battery is a 1500mah single Li_Ion cell and the wall charger is putting out 1000ma it will take approx 1.5 hours to charge. a USB port at 500ma will take approx 3 hours to accomplish the same thing.

now if the wall charger had an output of 1500ma it would charge in 1 hour at a rate of 1C. Charging above 1C will reduce the life (total number of charges the battery can take).. while charging below 1C will slightly extend the life of the battery
#4 mysticmead, Feb 15, 2010
Like Mysticmead says... There are tolerances which the battery will safely sustain. The listed voltage and amperage rates are used on the chargers for a reason... they are set to meet those tolerances for a variety of reasons. HEAT is the No.1 killer of any phone and it's components, charging at a faster rate may be possible but there are risks to do so. Those risks include permanently damaging circuitry of the phone, components within from the heat generated by charging at accelerated rates and or to the battery itself (melt/explosion).

So to answer the double/twin USB cord question... Yeah, it's possible, by I wouldn't try it without the EXPECTATION that things would end badly. If you feel brave and find losing your battery and or phone is an acceptable risk then give it a whirl... just don't freak out when things are a mess... ;)

#5 cooolone2, Feb 15, 2010
I basically just read the same thing and came to that conclusion.

Question then: If I used a double pronged USB cord (2 USB ports going to my USB hub) do you or does anyone else know if this would provide 1A and thus do the same charge time as the wall charger? I dont have a double pronged usb cord handy or otherwise I'd just test it myself.
#6 LxMxFxD, Feb 15, 2010
me personally... I wouldn't risk it.. the charging circuitry for the USB portion of the phone is made for 500ma... doubling that could result in failure.
#7 mysticmead, Feb 15, 2010
Incorrect. THe wall charger puts out 1A.
#8 LxMxFxD, Feb 15, 2010
you're correct... I was thinking of something else at the time (I hate when work intrudes into import stuff like our phones).. but I will say this.. having tested MANY computers over the years.. getting one that actually sticks to the standards that they are supposed to follow is rare. your USB port might be putting out 4.5v at 600ma... or it might be 5v at 450ma... I have even seen a USB port that was putting out 6v at over 550ma... so take the chance and double it might get lucky and have a perfect 1000ma... or might come in less... then again.. you might be pumping 1200ma or also need to make sure that the doubler is not a series connection.. if it is then you'd have 10v (or more) and the same 500ma.. it has to be a parallel connection..

charging batteries is one of those things that you really don't want to mess around with unless you have the right tools.. in this case.. the wall charger or a single USB are the right tools (ok.. I do have a battery charger that will charge Li-ION and I can adjust the current)
#9 mysticmead, Feb 15, 2010
I highly doubt that 500mA is all we can get, I remember my old Touchpro had a hack that allowed the phone to charge at the TRUE max current of a USB port (maybe 800-900mA) I was successful with this on any computer so long as the fast-charge tweak was applied.
The problem is on the software level, someone needs to make a hack that just lets the phone allow for the max current of the usb port to be used.

As it stands, charging via computer/usb is nearly pointless at the current 500mA.
#10 iviyth0s, May 31, 2010