Smallest USB power supply?

[dutts]

I am looking to wire in USB power supplies for both my Nest Thermostat and Netatmo indoor weather station unit, both currently take power from their respective supplied micro-usb to usb cables which plug into wall power adapters. For cosmetic reasons I have limited space so would like to replace these two power supplies with a single low profile unit. I have a mains fused spur available in the place I want to wire these in. I have looked at the various USB wall socket options (like http://www.amazon.co.uk/gp/product/...tag=usbwallsockets-21&linkId=NS6OGXXKXQ3627BN) but a back box, along with the usb cable sticking out is too big.

My latest thinking is to buy something like a 5v power supply (from RS or maplin, something like http://uk.rs-online.com/web/p/product/6783760), and butcher some usb cables to hard wire them in, but does anyone have any alternative ideas? I see a lot of discussion about the usb power socket wall plates on here but I would like to ideally go a step further and hard wire them in to avoid the extra space taken up by the face plate and USB connectors.

Rich

 

[bernardgreen]

Using a reputable source for the power supply would make a lot of sense. The "quality" of many imported items sold via the internet is very poor. Failure of just one component in a poorly designed USB power supply could result in 230 volts AC being supplied instead of 5 volts. That would destroy the item it was supplying.

Remember that almost all compact mains to 5 volt PSUs are switch mode PSUs and are likely to have a minimum load.

Dual outputs have a minimum load requirement, see output current data (within datasheet).

Take less than that minimum load and the output voltage will not be garanteed to be correct.

 

[flameport]

This: http://cpc.farnell.com/stontronics/t3514eg/inline-power-supply-5v-2a-2-1mm/dp/PW02870 or similar.

The RS item is designed to be mounted inside other equipment, not suitable for use on it's own.

 

[plugwash]

Remember that almost all compact mains to 5 volt PSUs are switch mode PSUs and are likely to have a minimum load. Take less than that minimum load and the output voltage will not be garanteed to be correct.

My experience has been that with modern DC power supplies minimum load requirements are the exception not the rule. Still it is something to watch out for.

Dual outputs have a minimum load requirement, see output current data (within datasheet).

Take less than that minimum load and the output voltage will not be garanteed to be correct.

The text you have quoted from (which seems to be the blurb from the website, not a quote from the datasheet) is for the range as a whole (which covers a range of wattages and both single and dual output models). The statement you have quoted is for the dual output models, the specific model linked is a single output model.

Reading the actual data sheet (rather than the blurb on the website which you seem to have quoted from) for the model in question states a current output range of 0-10A

 

[bernardgreen]

Plug wash is of course correct, I did quote from the blurb, not the most accurate way to describe a product.

 

[dutts]

This: http://cpc.farnell.com/stontronics/t3514eg/inline-power-supply-5v-2a-2-1mm/dp/PW02870 or similar.

The RS item is designed to be mounted inside other equipment, not suitable for use on it's own.

Ah excellent, thanks. The reason I was looking at those like the RS example I linked to was that I also have a device which takes a 12V supply so was originally looking to see if I could get a dual output (5v and 12v) but I suppose if I got whatever I needed to mount this into it would probably be larger than a socket and wall adapter?. In that case would something like this do? Obviously ensuring that my three device's requirements don't exceed the spec.

Or would I be better off with this and this?

Rich