How to power a USB hub - Page 3

Vinster03XR · 01-03-2007, 09:01 PM

I wish I could run a DC-DC adapter... I'm running a laptop for a carPC and it needs 19VDC to run.. as for the charging, I removed the battery. So I'm treating it like a regular PC....

Vin

Curiosity · 01-03-2007, 10:40 PM

I use a 19V DC-DC. I think it had a cig lighter plug on it originally. I paid around $80 but they are probably cheaper now. Check eBay.

You should keep the battery in it for unattended shutdown.

musters · 01-04-2007, 01:56 PM

I actually found a very neat solution recently to power a usb hub. There are tons of cellphone car chargers that charge via usb. All pushing out 5V 400ma - 500ma. So you can either get a usb hub that is powered by a usb cable, or get one that isn't, and just rip the cellphone car charger apart and you've got a very easy solution to powering the hub.

Vinster03XR · 01-04-2007, 10:24 PM

Quote: Originally Posted by Curiosity

I use a 19V DC-DC. I think it had a cig lighter plug on it originally. I paid around $80 but they are probably cheaper now. Check eBay.

You should keep the battery in it for unattended shutdown.

I'll have to look into that, when I first started this project a year ago I found nothing..

Vin

spoonraker · 01-05-2007, 04:31 PM

Well I definitely know what you're saying about powering it with a modified cell phone charger or something similar, the problem is they are all too low amerage.

Most of them are between 400-700mA, I went to RadioShack, circuit city, and best buy and looked at almost every cell charger.

My problem is the AC adapter on my hub puts out 3000mA at 5v.

Maybe I just need to buy a new hub that requires less power? Any suggestions? I had a hard time finding how many amps most of them need to run by looking at the box, so if anybody knows how many amps a specific hub needs and has a link to it that would be awesome.

Some of you guys that have done the cell charger trick, can you maybe point me to the exact hub you used?

Curiosity · 01-05-2007, 05:46 PM

You'll get 500mA from the PC it's plugged into. If the devices on the hub need more and have an external 5V jack, connect the cell charger to that. Most devices don't need anywhere near 500mA. The hub itself uses about 100mA and you can check the max power of the others devices by looking at the power info of the hub in device manager and total up all the devices connected to it.

Ruffy · 01-05-2007, 09:49 PM

Quote: Originally Posted by Vinster03XR

I wish I could run a DC-DC adapter... I'm running a laptop for a carPC and it needs 19VDC to run.. as for the charging, I removed the battery. So I'm treating it like a regular PC....

Vin

you can and probably will have to for the best/cleanest install

personally im thinking of getting a 12V/5V Out DC/DC Converter. Using that for my usb hub and my screen. and getting a Laptop power adapter(Basically another DC/DC Converter) For my laptop.

Sad thing is I'll be spending $100 just to power a usb hub and a touchscreen.

Currently my laptop and screen are being plugged into a DC/AC Inverter. I hate it. Laptops in the back seat because I cant decide what im going to do.
The Inverter's been hardwired into the car. I installed AC Jacks in the rear cabin that are easily accessable and can be trigger via a rocker switch. Currently I flick that switch everytime i get in or out of the car. I need to start cleaning things up and making it auto turn on without my intervention.

On top of that I'd like to create a box with some bypass switches that allow the laptop/carpc to be turned on when the car is off. My install keeps getting more and more complicated

spoonraker · 01-06-2007, 12:25 AM

The AC adapter my USB hub came with, the one that plugs into the external 5v port, puts out 3000mA, that's in addition to the 500mA from the USB connection.

If I'm simply going to replace the 3000mA AC adapter with a 12v DC current converted to 5v, don't I still need 3000mA going into the external 5v port? If that's the case none of the cell chargers would work since they only provide at most 700mA of power.

Curiosity · 01-06-2007, 12:51 AM

The AC adapter is provided with the hub as an option. You don't need it unless the total power consumed is over 500mA. USB powered, the hub provides 500 total. Externally powered, it disconnects the USB source power and provides 3000 total, but still 500 max per port. 500 being the max which is why it can only get that much from the USB port that it's connected to.

Ruffy · 01-06-2007, 12:52 AM

Quote: Originally Posted by spoonraker

The AC adapter my USB hub came with, the one that plugs into the external 5v port, puts out 3000mA, that's in addition to the 500mA from the USB connection.

If I'm simply going to replace the 3000mA AC adapter with a 12v DC current converted to 5v, don't I still need 3000mA going into the external 5v port? If that's the case none of the cell chargers would work since they only provide at most 700mA of power.

a cell phone charger would at best power a few low powered items. Just because the AC Adapter is rated at 3A Doesnt mean you'll be drawing 3A so no you dont NEED the 3000mA.

Really you need to measure the mA usage of all your devicesa nd find out how much you truly need. You do want some headroom in case you want to add something else.

Could always get a cellphone charger per device. Would get expensive and tiring quick to install them all. Basically using each as a Point of Load DC Regulator. Still could be done cheaper than buying a Carnetix for both 12v/5v output @ $100, or just a 5v dc/dc for $50

spoonraker · 01-06-2007, 04:04 AM

I guess I'll just buy the highest output charger I can find and hope for the best, I'll be sure to let you know how it goes.

I think I saw a universal charger that went up to 2500mA, it even had adjustable voltage, the only problem I saw was that it didn't have 5v operation as an option. I think 6v and 4.5 were as close as it came...would either of those work? I'm guessing no...

yonu · 01-08-2007, 02:22 PM

stupid question and hopfully someone can help me out, I have been though several call phone chargers however all of them seem to put out 6.9v at 500MA can any suggest a brand that puts out 5v? as I would assume i can't pipe 6.9v into the usb hub.