when i use my HTC thunderbolt as a GPS in the car and plugged into my griffin dual-USB port charger, it never really seems to charge...just maintain the current power level



i assume that's because it's using just enough (or perhaps just a tad less) power than it's getting from the charger and as such, doesn't charge...since it will actually charge when i have it simply plugged in (but screen off and no GPS app running), it charges

i have one of those Y-cables that used to come with external hard drives back in the day when some enclosure/HDD combinations wouldn't get enough power from the USB ports and you'd plug the single cable into two ports to power it...would using one of these cables allow me to fast-charge my phone?

the griffin adapter is NOT compatible with the ipad (apparently each port doesn't supply enough mA?)...so i assume the voltage is the same (5V), but it would multiply the amperage supplied to the phone (500mA to 1000mA), thereby allowing for fast charging

good idea, do-at-your-own-risk-but-will-probably-not-blow-up-your-phone idea, or zomg-dont-do-it! idea?

5/3/2012 7:11:16 AM

Quote :

"good idea, do-at-your-own-risk-but-will-probably-not-blow-up-your-phone idea, or zomg-dont-do-it! idea?"

you phone pulls the current, the adapter doesnt push it. You will not blow up your phone. IIRC that adapter is rated at 1A per usb port. The two things that pull the most current on that phone are the gps and the 4G. You are prob just pulling about as much current as you are using.

you will be fine using the dual USB.

5/3/2012 8:12:38 AM

Quote :

"you phone pulls the current, the adapter doesnt push it."

i feel dumb because i knew this...just forgot until you wrote it

and in that case, i might as well give it a shot...google gives me a bunch of different things, the most likely of which (in my mind) is that it will recognize the charger as a USB port and limit the current to 500mA regardless of what it's actually offering

but since it shouldn't hurt it, might as well give it a shot...thanks for the feedback

5/3/2012 8:26:44 AM

The rating of that adapter might also be for total power output, not just each USB port. My old droid barely charges when using GPS navigation and the battery gets pretty warm so I know it's sucking up some power as well.

5/3/2012 8:32:09 AM

^ if that's the case and the thunderbolt is willing (ie. isn't limited to 500mA), then the Y-cable might still help, yes?

edit: actually, i think specialkay is right: http://store.griffintechnology.com/powerjolt-dual-micro

Quote :

"5 watts per port (5 volts @ 1 amp) for fast charging "

i'm very surprised that it doesn't charge (just maintains) at 1A...which leads me to believe that it might recognize the charger as a USB port and limit itself to 500mA...is that plausible?

[Edited on May 3, 2012 at 8:38 AM. Reason : link]

5/3/2012 8:34:27 AM

500ma will charge that phone but very slow

1a will charge it, I bet if you look at your oem charger its 1amp

5/3/2012 8:43:41 AM

My DX does the same thing. I have an OEM charge that is close to 1A and it can only hold the current charge when using nav/screen is constantly on.

5/3/2012 9:50:07 AM

if you want to get ass backwards about the whole thing, get a small inverter and plug the AC charger in. Im assuming the AC charger will give it more amps.

5/3/2012 12:35:38 PM

Quote :

"you will be fine using the dual USB."

5/3/2012 1:01:44 PM

Logically, yes. But you are forgetting how this works. The phone pulls the current, the charger doesn't push it. How it knows how much it can legally pull is by asking the charger over the data lines (either digital negotiation or by checking for a particular circuitry). As such, even if your charger is rated to 10A, if the circuitry there-in contained is not what your phone is expecting from its OEM charger, or is blocked by the Y-adapter, your phone may pull as little as 100mA (the USB standard when negotiation fails).

As such, the only way to know is to try it and measure the current. Or, buy your phone's OEM charger.

All that said, there was a rom hack available for my old phone which would force the charging circuit to always pull the maximum current of 800mA regardless of what it was plugged into. I never used it, but I seriously considered it.

[Edited on May 3, 2012 at 11:57 PM. Reason : .,.]

5/3/2012 11:55:34 PM