Possible to power a USB from SW tank?

[Takahashi]

Is it at all possible to run a powered USB hub off an SW powertank? The tank only has 3, 6, and 9 volt DC outs, all @ 1a each, but any powered hub I've seen appears to need 5v @ 2+ amps...

Any help would be greatly appreciated, as this is probably my only remaining hurdle to get the AP kit up & running. Well, that, and the half-a-grand for a CCD guider, but that's another story.

[great_bear]

any powered hub I've seen appears to need 5v @ 2+ amps...

I don't think that's what the hub needs, as such - it's more like that's what current might be drawn in the worse-case scenario if you hung a USB-powered device off every port on the hub.

You're not planning on doing that are you?

[Mikea]

You'd need to check whether the hub has a built-in 5V regulator that will cope with a 6V input, or if it just passes the DC input straight through. Yoi could be in trouble if it's the latter.

[Takahashi]

The voltage and amperage requirements I mentioned were simply read off the power-supply (wall-wart) labels of a couple of USB hubs I've seen recently, and there does appear to be some variation between them. I think I understand what you're saying about it only using this power to cover specific "demands" of certain peripherals that might be plugged into it, but unfortunately I'm looking at having at least two devices that absolutely require power assistance (if not complete dependence on it) from the hub :

1 - USB wireless dongle (for gamepad) definitely relies on USB power.

2 - USB from Lodestar CCD, definitely requires USB power.

3 - USB connection to dSLR, may need some power outwith the camera's battery for passing data?

Other than that, I'll have a laptop connected to the hub via USB for all scope / camera controls, and the HitecAstro EQDIR also plugged into the hub from the 9-pin RS232 on the EQ6. Not sure how much power it will require from the hub, if any. The wireless dongle that will control the gamepad could easily be plugged directly into a spare USB on the laptop, but I'd rather not have such a thing protruding from the lappy when I'm "in the field", as I've seen many a minor disaster occur in this way.

[PhillyDee]

USB from a port is 500mA. So if it has 4 ports it is rated at 2 Amps. I think thats where the value comes from. You could use a voltage divider to get the 5v, or you could buy one of those cigarette lighters from Asda (and others) that actually has 2 x 12v ports and 2 USB ports.

[Merlin66]

I had similar problems..

The answer was a 12V 2A car plug to a 5V small pin connector ( to suit the power IN socket on the USB hub) from Maplins. Works a treat!

[Takahashi]

Merlin, that sounds exactly what I need!

Do you have a link to it on Maplins site? I've tried a few variations of "12V to 5V" in Google, but the only Maplins link I found took me to a general converters page,

[Merlin66]

It's a #A92JH - 3A Car Power Adaptor.

Universal 3A DC Power Supply : All Products : Maplin

Ken

[Takahashi]

Superb, thanks... and only 10 quid too.

[Merlin66]

I also use the similar 140W 12V -15V/ 18V car power adaptor to give an extra grunt to drive the HEQ5pro (15V) and the Lx200 (18V). Certainly makes sure there's sufficient power at the mount!!

Ken