USB Hub not working on 12v

[alfista]

Hi all,

I have an Anker 3+7 port hub (three charging ports, seven device ports). It comes with a 12v 5a power brick and I'm trying to run it off of 12v instead of using the brick. I've run a new 12v line and confirmed proper polarity of the tip, but the hub will not power on with it. Voltage is identical to what the power brick is providing. Is the hub 'confirming' that I am not using the OEM's brick? I would think the fuse would blow if it tried to draw too much power, but the line is still providing power.

Any thoughts?

[rsdata]

Are you sure it is 12V and not 5 or 6 Volt? It should say on the brick. Does the hub still work with the supplied brick plugged into 120AC, or is it blown?

If it still works with the brick and not hooked to 12V on your camper, then something has to be overlooked as these things are NOT "smart".

[alfista]

Brick definitely outputs 12v 5a and the hub still works fine with it.

I must be missing something, but I can't figure out what. I have a second (but different model) hub installed in this manner and it is working fine.

[Flybob]

There is some intelligence in the USB chips ( will shut down if excess power is drawn from one port) however they do not have any way of checking where their input power is coming from. They may however shut down if the input is above a certain voltage. Check the voltage at the output of the new line you ran. Most 12V RV systems ( when connected to shore power) will actually be closer the 13+ volts as that is the voltage provided to the battery by the converter. You can also try disconnecting shore power and letting the battery rest an hour or two and try with just battery.

[Toddupton]

Don't know why it would be a 12 volt brick when usb only wants 5v/dc that is strange it would not work.

[Flybob]

Description of one model from their web site.

Anker® USB 3.0 9-Port Hub + 5V 2.1A Smart Charging Port with 12V 5A Power Adapter

[mikes86gn]

I can't tell without the adapter in my hand, but your adapter just might be 120vac to 12vac. The device then will take the 12vac input and convert it to 5vdc. If that's the case a 12vdc input won't work.

[Radio]

Originally Posted by Toddupton

Don't know why it would be a 12 volt brick when usb only wants 5v/dc that is strange it would not work.

It has to do with having enough "overhead" to filter out noise and ripple that may be riding on the 12 vdc line to get a very pure 5 vdc. Also, 12 vdc wall warts are plentiful and cheap.

[Bocamo]

From the photos the brick appears to be substantial. The device can apparently output 10 amps at 5V or 50 watts. internally the device has to limit power to the individual ports (2.1A to the 3 smart ports). The device is probably looking for a very regulated 12V supply and you are not likely to get it from your 12V wiring. Overvoltage should make this device go into protection mode. I wouldn't suggest running this particular hub off of a raw DC input. You might check with Anker on this. An easy way to verify this hypothesis would be to just power it up from a bench supply.

[alfista]

Thanks everyone. As I'm doing more with the camper, raspberry pi's and arduinos I'm learning that not all current is created equal. I'm going to run it from 120v in the meantime, but feel like that is a waste.

Any tips on what kind of device do I need to run clean 12v power that this would respond properly to? I also have a Ubiquiti PoE device that requires 24v that I need to figure out as well.

[dwrichards]

I have been adding 12v gadgets also. Consider getting a few of these to keep on hand:
http://www.amazon.com/Nextrox-Conver.../dp/B00A71CMDU
There are waterproof versions and versions that take a wider voltage range.

[redwolf]

It most likely has a switching power supply to generate the 5v for the sub connectors.

Depending on the chip set inside the hub it may not switch on the charging ports until it's plugged into a host and enumerates. Some of them will then continue to support the charging until the 12v is cycled.

Martin