Overclock.net › Forums › Mobile Computing Forum › Tablet Computers › Are these "Amperage step up" adapters safe to use?
New Posts  All Forums:Forum Nav:

Are these "Amperage step up" adapters safe to use?

post #1 of 5
3/27/12 at 11:52pm
Thread Starter 
I was looking around on ebay/google for a usb charging solution for my HP touchpad when I found this:

http://www.amazon.com/Switching-Charging-Charger-Adapter-Convertor/dp/B006JXOROC

Pisen is one of the better china brands, but I'm wondering if these are safe to use? It apparently steps up the 0.5Amps from a usb port to 2A, enough to feed an iPad etc.
$3 shipped on ebay for those who are looking for one.

Cheers


300
I-It's not like I want to overclock you or anything... baka!
(15 items)
 
X220
(6 items)
  		 
CPUMotherboardGraphicsRAM
Intel Core i7-3820 MSI X79-GD45 MSI GTX465 GE unlocked to 470 16GB Corsair Vengeance LP 
Hard DriveHard DriveHard DriveHard Drive
128GB Crucial M4 1TB WD Black 1TB WD Black 640GB WD Black 
Hard DriveCoolingOSMonitor
2TB WD Green Noctua D14 Windows 7 Ultimate 64-Bit 2x Samsung 22" 2253BW 
PowerCaseAudio
Corsair HX650 Fractal Define R2 Fii E10 DAC 
View all
CPUGraphicsRAMMonitor
Core i5 2520 Intel HD3000 Gskill  12.5" IPS 
CaseMouse
Thinkpad NUB 
View all
  hide details  
Reply
I-It's not like I want to overclock you or anything... baka!
(15 items)
 
X220
(6 items)
  		 
CPUMotherboardGraphicsRAM
Intel Core i7-3820 MSI X79-GD45 MSI GTX465 GE unlocked to 470 16GB Corsair Vengeance LP 
Hard DriveHard DriveHard DriveHard Drive
128GB Crucial M4 1TB WD Black 1TB WD Black 640GB WD Black 
Hard DriveCoolingOSMonitor
2TB WD Green Noctua D14 Windows 7 Ultimate 64-Bit 2x Samsung 22" 2253BW 
PowerCaseAudio
Corsair HX650 Fractal Define R2 Fii E10 DAC 
View all
CPUGraphicsRAMMonitor
Core i5 2520 Intel HD3000 Gskill  12.5" IPS 
CaseMouse
Thinkpad NUB 
View all
  hide details  
Reply
post #2 of 5
3/28/12 at 5:00pm
I thought USB (from a computer) could deliver 0.5A max @ 5V--I'm confused by this contraption--how does it allow a draw more than what the port can supply?

If you're using a higher-current source (like a wall plug or a car plug), they should be capable of delivering 2A already, right?

What device is this for?
My New Middle-of-the-Road System
(13 items)
  		  
CPUMotherboardGraphicsRAM
i5-2500K Biostar TP67B+ XFX HD5750 1GB 2x4GB DDR3 Corsair 1600 
Hard DriveOSMonitorPower
60GB OCZ SSD, 2x160GB HDD RAID0, 500GB+500GB+1.5TB Windows 7 Ultimate 64-bit Samsung SyncMaster 930B Antec SmartPower 450w 
Case
Antec 900 
View all
  hide details  
Reply
My New Middle-of-the-Road System
(13 items)
  		  
CPUMotherboardGraphicsRAM
i5-2500K Biostar TP67B+ XFX HD5750 1GB 2x4GB DDR3 Corsair 1600 
Hard DriveOSMonitorPower
60GB OCZ SSD, 2x160GB HDD RAID0, 500GB+500GB+1.5TB Windows 7 Ultimate 64-bit Samsung SyncMaster 930B Antec SmartPower 450w 
Case
Antec 900 
View all
  hide details  
Reply
post #3 of 5
3/28/12 at 9:13pm
Thread Starter 
Quote:
Originally Posted by guyladouche View Post

I thought USB (from a computer) could deliver 0.5A max @ 5V--I'm confused by this contraption--how does it allow a draw more than what the port can supply?
If you're using a higher-current source (like a wall plug or a car plug), they should be capable of delivering 2A already, right?
What device is this for?

It's supposed to somehow make your usb port supply 2A, but wouldn't that lower the voltage?

I'm hoping theres someone who knows how this might work as my electrical knowledge is next to none tongue.gif
I-It's not like I want to overclock you or anything... baka!
(15 items)
 
X220
(6 items)
  		 
CPUMotherboardGraphicsRAM
Intel Core i7-3820 MSI X79-GD45 MSI GTX465 GE unlocked to 470 16GB Corsair Vengeance LP 
Hard DriveHard DriveHard DriveHard Drive
128GB Crucial M4 1TB WD Black 1TB WD Black 640GB WD Black 
Hard DriveCoolingOSMonitor
2TB WD Green Noctua D14 Windows 7 Ultimate 64-Bit 2x Samsung 22" 2253BW 
PowerCaseAudio
Corsair HX650 Fractal Define R2 Fii E10 DAC 
View all
CPUGraphicsRAMMonitor
Core i5 2520 Intel HD3000 Gskill  12.5" IPS 
CaseMouse
Thinkpad NUB 
View all
  hide details  
Reply
I-It's not like I want to overclock you or anything... baka!
(15 items)
 
X220
(6 items)
  		 
CPUMotherboardGraphicsRAM
Intel Core i7-3820 MSI X79-GD45 MSI GTX465 GE unlocked to 470 16GB Corsair Vengeance LP 
Hard DriveHard DriveHard DriveHard Drive
128GB Crucial M4 1TB WD Black 1TB WD Black 640GB WD Black 
Hard DriveCoolingOSMonitor
2TB WD Green Noctua D14 Windows 7 Ultimate 64-Bit 2x Samsung 22" 2253BW 
PowerCaseAudio
Corsair HX650 Fractal Define R2 Fii E10 DAC 
View all
CPUGraphicsRAMMonitor
Core i5 2520 Intel HD3000 Gskill  12.5" IPS 
CaseMouse
Thinkpad NUB 
View all
  hide details  
Reply
post #4 of 5
3/28/12 at 9:19pm
Quote:
Originally Posted by cgg123321 View Post

It's supposed to somehow make your usb port supply 2A, but wouldn't that lower the voltage?
I'm hoping theres someone who knows how this might work as my electrical knowledge is next to none tongue.gif

Witchcraft I tell you!

But I don't understand--since it's passive, you can't increase the amount of current.

Okay, I just looked around, and found this:
http://androidforums.com/samsung-galaxy-nexus/500497-1a-2a-car-charger.html#post3946933

Devices recognize something as either a "USB" (data) port, or an "AC" (technically DC, but whatever) connection. Apparently if the port is configured like a computer USB data port, the device itself will recognize that and only draw up to 0.5A. If the port is configured NOT as a "USB" data port, the device can draw up to 2A. It seems to just be a slight change of not shorting the two data usb pins on the usb port which tells the device it's not a usb data port, but rather a strict charging port.

Don't see why they wouldn't be unsafe in that case--the device will still only draw as much current as it is allowed (by the circuit in the battery--batteries are pretty smart these days).

edit--But if you're plugging the device into a computer usb port, you will still only get 0.5a since that's all the computer port can supply (I think technically usb 3.0 can output up to 0.9a)--this is probably more for wall chargers that are still only putting out 0.5a
Edited by guyladouche - 3/28/12 at 9:25pm
My New Middle-of-the-Road System
(13 items)
  		  
CPUMotherboardGraphicsRAM
i5-2500K Biostar TP67B+ XFX HD5750 1GB 2x4GB DDR3 Corsair 1600 
Hard DriveOSMonitorPower
60GB OCZ SSD, 2x160GB HDD RAID0, 500GB+500GB+1.5TB Windows 7 Ultimate 64-bit Samsung SyncMaster 930B Antec SmartPower 450w 
Case
Antec 900 
View all
  hide details  
Reply
My New Middle-of-the-Road System
(13 items)
  		  
CPUMotherboardGraphicsRAM
i5-2500K Biostar TP67B+ XFX HD5750 1GB 2x4GB DDR3 Corsair 1600 
Hard DriveOSMonitorPower
60GB OCZ SSD, 2x160GB HDD RAID0, 500GB+500GB+1.5TB Windows 7 Ultimate 64-bit Samsung SyncMaster 930B Antec SmartPower 450w 
Case
Antec 900 
View all
  hide details  
Reply
post #5 of 5
3/28/12 at 9:44pm
Thread Starter 
That's what confuses me, the theoretical max current output from a USB port is 0.5A (as I have been told). It doesn't seem to make sense that an adapter would somehow allow it to output more, without drawing power from an external source.

Anyways, thanks for the reply. I ordered one earlier for $3 shipped so I'll see if it actually works and report back:thumb:
I-It's not like I want to overclock you or anything... baka!
(15 items)
 
X220
(6 items)
  		 
CPUMotherboardGraphicsRAM
Intel Core i7-3820 MSI X79-GD45 MSI GTX465 GE unlocked to 470 16GB Corsair Vengeance LP 
Hard DriveHard DriveHard DriveHard Drive
128GB Crucial M4 1TB WD Black 1TB WD Black 640GB WD Black 
Hard DriveCoolingOSMonitor
2TB WD Green Noctua D14 Windows 7 Ultimate 64-Bit 2x Samsung 22" 2253BW 
PowerCaseAudio
Corsair HX650 Fractal Define R2 Fii E10 DAC 
View all
CPUGraphicsRAMMonitor
Core i5 2520 Intel HD3000 Gskill  12.5" IPS 
CaseMouse
Thinkpad NUB 
View all
  hide details  
Reply
I-It's not like I want to overclock you or anything... baka!
(15 items)
 
X220
(6 items)
  		 
CPUMotherboardGraphicsRAM
Intel Core i7-3820 MSI X79-GD45 MSI GTX465 GE unlocked to 470 16GB Corsair Vengeance LP 
Hard DriveHard DriveHard DriveHard Drive
128GB Crucial M4 1TB WD Black 1TB WD Black 640GB WD Black 
Hard DriveCoolingOSMonitor
2TB WD Green Noctua D14 Windows 7 Ultimate 64-Bit 2x Samsung 22" 2253BW 
PowerCaseAudio
Corsair HX650 Fractal Define R2 Fii E10 DAC 
View all
CPUGraphicsRAMMonitor
Core i5 2520 Intel HD3000 Gskill  12.5" IPS 
CaseMouse
Thinkpad NUB 
View all
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Tablet Computers
Overclock.net › Forums › Mobile Computing Forum › Tablet Computers › Are these "Amperage step up" adapters safe to use?