Being informed that there has been a "power surge on a hub port", followed by malfunctioning or absolute non recognition of the device that is connected to one of the USB ports of the computer or USB hub, is a frequent nuisance faced by people using Windows-powered systems. Techspirited provides solutions for this problem as well as tips to avoid it.
Power Rating of USB ports
Any standard USB port―before the USB 3.0 era, that is not a charging, power-delivering, or a self-powered hub port―has the following typical power rating.
Maximum Current: 500mA to 900mA
Maximum Voltage: 5V ± 25mV
On a laptop that is approximately three or four years old, one generally finds USB ports with the rating mentioned above.
Quite often than never, we have all faced this typical problem. We plug an external device which could be anything from our digital camera, iPod, or smartphone to a 1TB-capacity hard drive into our computer with the help of a USB connector data cable. Things seem to progress normally, when suddenly, we get slapped with the following message:
| Power Surge on Hub Port A USB device has exceeded the power limits of its hub port. |
after which, things just go downhill from the USB ports only recognizing our devices intermittently to their complete malfunctioning. A fact that not too many people are aware of, is when excessive power is drawn by a device through a USB port, it will not only damage the port itself but the computer’s motherboard as well. For this precise reason, it is advisable to know beforehand, how much power a device would draw when it is connected to a USB port, so as to avoid unforeseen damages.
How to Avoid A”Power Surge on Hub Port”
Here are a few pointers to help avoid this situation from the very first instance itself.
♦ If you wish to plug your device into your computer to charge it, use the charging USB port rather than the standard one. The reason is charging ports are well-equipped to draw in more power than a standard one. Hence, they are optimized to charge your device.
♦ If only those devices that actually need to communicate with a computer are plugged into the hub rather than each and every device that has a USB-connect capability, the chances of overloading the hub are reduced. For example: a USB-connected table fan or a lava lamp can function perfectly without being connected to a computer. There are two ways to work around this:
☞ You can run the device with a USB adapter that can be directly connected to an power socket.
☞ You could daisy-chain (plug one hub into another hub) your connection. However, daisy chaining would increase the time lag in the communication with the computer, especially if you are using the USB 1.x standard.
♦ Low-cost, poor-quality, multi-port USB hubs are deemed inefficient in regards to load management. Instead of these, you could opt for a self-powered hub which not only has sufficient number of ports but also has the ability to draw power from an external power source instead of the computer it is connected to. It, thus, safeguards your computer and other devices from power surge damage.
How to Fix A “Power Surge on Hub Port”
Let’s troubleshoot this issue right from the root.
♦ Check whether the fault lies with the cord that you are using. Probably, its connector and/or cable may not be equipped to handle a lot of power. Double-check the power rating of both and compare the values with that of the port. If you are in doubt, you can obtain the power rating of your USB ports by following these steps:
☞ Type “Device Manager” in the search box of the Start menu. Look for USB Root Hub nested inside the tree of theUniversal Serial Bus Controllers.
☞ To individually take a look at the properties of each port, right-click the root hub’s listing and select Properties from the drop-down menu. This will show you the maximum voltage and current allowed for the different ports.
In case you find that the cable is the cause of the problem, replace it with another one and check if the problem persists.
♦ As soon as the other factors are ruled out, remove each device connected to the hub (or the ports directly on your computer), one by one. This is an easy way to find the device responsible for the problem. However, if in spite of removing every connected device, you still get the same message of the “Power Surge” problem, the fault could lie with the drivers for the USB port. Here are a few steps to guide you to resolve this:
☞ Open the Device Manager (Control Panel → Hardware and Sound → Device Manager) once more.
☞ Click on Scan for Hardware Changes. This will reveal the USB port that has been affected by the power surge problem.
☞ Uninstall all the drivers for every USB port accessible by your computer. This can be done by clicking on Universal Serial Bus Controllers to expand it, and then right-click each device listed under that, and click on Uninstall.
☞ Shut down your computer.
☞ If you are using a laptop computer that has a detachable battery, remove the battery, and then press down the power button for a few seconds. This will drain out the capacitors on the USB ports of any residual charge, and assist in the process of resetting your ports.
☞ Switch on your computer, and start Windows as you normally do.
☞ Allow your computer to discover the device connected by you, and install the corresponding drivers by itself.
♦ Sometimes, an error message pops up for no reason at all, and in fact, when checked, all the available USB ports as well as the devices connected to them are working perfectly. Tech forum rumor mills suggest that this entire problem is sometimes nothing more than a Windows glitch. If you are absolutely sure (do verify this more than once) that the message does not really imply impending damage to both your computer and to the external devices connected, feel free to disable the feature that informs you of errors. Here’s how:
☞ Open Control Panel → Hardware and Sound → Device Manager, and in the application, right-click on any USB Universal Host Controller listing, which is nested within the Universal Serial Bus Controllers tree.
☞ From the drop-down menu, select Properties, and go to the Advanced tab in the window that opens.
☞ Click on the check box against Don’t Tell Me About USB Errors. You are good to go now.
A good tip to prevent power surges in your USB ports is to plug in the USB connector while the computer is switched off. The reason being, many a time, unusually large amounts of power, are drawn by the device the moment it is connected to the USB port. Always exercise caution if you encounter this error message while you are working with a high capacity removable hard disk drive with important files. The impact of the high power surge could burn the USB-to-SATA bridge (in simple words, your device will not be recognizable on any other computer, you will have difficulty in recovering your data), or even worse, corrupt the contents on the drive.
We hope our simple guide to resolve the problem of “Power Surge on Hub Port” was helpful.