Don't know the power draw but can't imagine its very large. Why not just use an inverter?

tkr001:

 

Why not just use an inverter?

There are quite a few set top boxes out there with stupidly large power use, both when operating and in standby.  So it is a good question to ask.  It is not too difficult to make boxes low power these days, but it does take a little effort.  For a box that may eventually wind up having 100,000 or more running in the country, it would be a good idea not to make it use too much.  If it draws 5 watts on standby then that would be 500 kW the electricity grid would have to provide.  Preferably, STBs should draw less than 0.1 W on standby.  Ideally, less than 10 mW, and it is actually not too difficult to do that unless there is a hard drive inside.

I use the Sky box for recording, and access to sports channels. The problem with the old sky box is that it takes an age to re-tune itself after being powered down, and it consumes ~ 35W when recording in standby mode. Because of its power consumption it spends most of its time off, but it would be nice to have a device that is as capable as the Sky box is, at setting and recording programs, but consuming say 20% of the power of the current box, and with the ability to 'boot' up and tune in promptly.

fe31nz:

 

For a box that may eventually wind up having 100,000 or more running in the country, it would be a good idea not to make it use too much.

 

I used to work for Sky UK. The set top box designers did a presentation about the latest box once, and mentioned they were so conscious of this they wouldn't put another LED indicator on the front of the box without a really good justification. I forget the exact numbers of installed boxes, but it was the first time I had really thought about multiplicative effect of a seemingly insignificant power use; the cumulative power used was astonishing to me.

spmiller:

 

fe31nz:

 

For a box that may eventually wind up having 100,000 or more running in the country, it would be a good idea not to make it use too much.

 

 

I used to work for Sky UK. The set top box designers did a presentation about the latest box once, and mentioned they were so conscious of this they wouldn't put another LED indicator on the front of the box without a really good justification. I forget the exact numbers of installed boxes, but it was the first time I had really thought about multiplicative effect of a seemingly insignificant power use; the cumulative power used was astonishing to me.

 

So if a power company starts offering a pay TV service with a set top box - we should definitely keep a close eye on their offering.
(Lightbulb moment). Is THAT why the power companies offer a 'free TV' with its contracts? 

OK, so no one seems to have an answer to that query. How about this. Is the current sky box capable of being powered directly by 12v DC?

Have you asked Sky directly? They should be able to give you an answer, and likely (if the answer is yes) supply any necessary connectors as well.