Question Fry USB 2.0 Port?

[VegasBobby]

I own the patent on a counterfeit detector we may sell to a large chain of retail stores. Normally the counterfeit detector is powered by a wall adapter but the chain wants to power the detector from a computer cash register using a USB 2.0 port. The USB ports operate at 5VDC with a maximum of 500mA. My device will use all of that and maybe a little more amps. Perhaps as much as 550mA. We have tested it and it works fine. I’m worried however that we may fry the cash register motherboard. It’s been my experience in the past that if a device requires too much current on a USB 2.0 port it just won’t work. Is that the case or can we fry the cash register motherboard?

 

[RememberThe5th]

You wont fry.
As the current is higher than max specified (also varies a lot), the voltage will drop.
Ive tested that with usb voltage/amp meter.

Only if you short it the fuse will go down or the chip that gives voltage to the usb port or controller.

 

[Deleted member 14196]

As long as you don’t go over the 550 mA you should be fine

 

[VegasBobby]

That was my thinking too. If the device tries to pull too much current or voltage the motherboard just won't supply it. I tried to run a USB powered hard drive once from a USB port and it didn't fry my board, it just didn't work. A board can't supply something it doesn't have. At least that's my thinking which of course could be wrong but it seems reasonable. Who could I contact to get a definitive answer I could use to tell my customer before I sell them thousands of my counterfeit detector?