<![CDATA[#Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains?]]> nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? I have a board that consumes a peak of about 2.4w, but most of the time only consumes 0.35w. Having a mains to 3.3v or mains to 5v adaptor that is drawing more than the device most of the time seems a poor choice.

Any recommendations?

]]>https://forum.fedi.dk/topic/dbe53e16-fdff-4b55-a394-e9c892f9a341/electronics-nerds-of-the-fediverse-what-s-the-most-efficient-way-of-powering-really-low-power-devices-from-the-mainsRSS for NodeSun, 05 Jul 2026 04:59:05 GMTFri, 19 Jun 2026 12:07:35 GMT60<![CDATA[Reply to #Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? on Fri, 19 Jun 2026 12:52:41 GMT]]>@wmd @moof perminantly, it's for building sensor network.

]]>https://forum.fedi.dk/post/https://social.v.st/users/quixoticgeek/statuses/116776865695392664https://forum.fedi.dk/post/https://social.v.st/users/quixoticgeek/statuses/116776865695392664Fri, 19 Jun 2026 12:52:41 GMT<![CDATA[Reply to #Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? on Fri, 19 Jun 2026 12:51:36 GMT]]>@quixoticgeek @moof how long does it need to run?

]]>https://forum.fedi.dk/post/https://chaos.social/users/wmd/statuses/116776861442394719https://forum.fedi.dk/post/https://chaos.social/users/wmd/statuses/116776861442394719Fri, 19 Jun 2026 12:51:36 GMT<![CDATA[Reply to #Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? on Fri, 19 Jun 2026 12:35:48 GMT]]>@pndc Brilliant, thank you!

]]>https://forum.fedi.dk/post/https://social.v.st/users/quixoticgeek/statuses/116776799316976231https://forum.fedi.dk/post/https://social.v.st/users/quixoticgeek/statuses/116776799316976231Fri, 19 Jun 2026 12:35:48 GMT<![CDATA[Reply to #Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? on Fri, 19 Jun 2026 12:33:46 GMT]]>@quixoticgeek I made a slight error, but not in a bad way. The datasheet is in the product bumph PDF. The one I linked to is actually 70mW at idle and provides up to 17W across 3 USB-A outputs. There is also a model which is 30mW at idle with 5W on its single USB output which is the PDF I was looking at: https://www.ikea.com/nl/en/p/smahagel-power-supply-kit-80604096/. There are a few other charger options with different idle draws and maximum power outputs in the general category: https://www.ikea.com/nl/en/cat/usb-chargers-40844/.

The product bumph PDFs are buried behind a load of clicks; thanks JavaScript. I clicked on "Product Details" then "Assembly and documents" and from there there's a PDF download link.

]]>https://forum.fedi.dk/post/https://social.treehouse.systems/users/pndc/statuses/116776791349300261https://forum.fedi.dk/post/https://social.treehouse.systems/users/pndc/statuses/116776791349300261Fri, 19 Jun 2026 12:33:46 GMT<![CDATA[Reply to #Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? on Fri, 19 Jun 2026 12:32:43 GMT]]>@kim @quixoticgeek POE is a nice idea.

]]>https://forum.fedi.dk/post/https://mastodon.social/users/_thegeoff/statuses/116776787202160815https://forum.fedi.dk/post/https://mastodon.social/users/_thegeoff/statuses/116776787202160815Fri, 19 Jun 2026 12:32:43 GMT<![CDATA[Reply to #Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? on Fri, 19 Jun 2026 12:32:00 GMT]]>@quixoticgeek At a guess, a solid state transformer (basically most modern phone chargers) is going to be the best bet, >90% efficiency. But thermodynamically you *have* to have losses, and anything converting mains (capable of kWs) down to single Watt range is going to seem very inefficient, the actual usage is comparable to the very minor loss in the transformer.
Rechargeable batteries, perhaps? With a controller you could have short bursts of charging for hours/days of usage?

]]>https://forum.fedi.dk/post/https://mastodon.social/users/_thegeoff/statuses/116776784428066131https://forum.fedi.dk/post/https://mastodon.social/users/_thegeoff/statuses/116776784428066131Fri, 19 Jun 2026 12:32:00 GMT<![CDATA[Reply to #Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? on Fri, 19 Jun 2026 12:23:11 GMT]]>@wmd @moof I thought about that, but it dramatically increases the complexity of the device.

]]>https://forum.fedi.dk/post/https://social.v.st/users/quixoticgeek/statuses/116776749754572313https://forum.fedi.dk/post/https://social.v.st/users/quixoticgeek/statuses/116776749754572313Fri, 19 Jun 2026 12:23:11 GMT<![CDATA[Reply to #Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? on Fri, 19 Jun 2026 12:22:31 GMT]]>@pndc ooh, where do you see the 30mW number I'm not spotting it on the ikea website anywhere obvious. But that would be ideal.

]]>https://forum.fedi.dk/post/https://social.v.st/users/quixoticgeek/statuses/116776747078431513https://forum.fedi.dk/post/https://social.v.st/users/quixoticgeek/statuses/116776747078431513Fri, 19 Jun 2026 12:22:31 GMT<![CDATA[Reply to #Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? on Fri, 19 Jun 2026 12:21:44 GMT]]>@moof @quixoticgeek this was my thoughts. Have a buffer like battery or elco, and only switch on supply when low.

]]>https://forum.fedi.dk/post/https://chaos.social/users/wmd/statuses/116776744000228935https://forum.fedi.dk/post/https://chaos.social/users/wmd/statuses/116776744000228935Fri, 19 Jun 2026 12:21:44 GMT<![CDATA[Reply to #Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? on Fri, 19 Jun 2026 12:19:46 GMT]]>@quixoticgeek IKEA's SMÅHAGEL supposedly only draws 30mW when unloaded and provides up to 1A/5W.

]]>https://forum.fedi.dk/post/https://social.treehouse.systems/users/pndc/statuses/116776736309001610https://forum.fedi.dk/post/https://social.treehouse.systems/users/pndc/statuses/116776736309001610Fri, 19 Jun 2026 12:19:46 GMT<![CDATA[Reply to #Electronics nerds of the fediverse, what's the most efficient way of powering really low power devices from the mains? on Fri, 19 Jun 2026 12:18:27 GMT]]>@quixoticgeek What kind of project is this? Are you comfortable designing PCBs with mains voltages? If so, there are PCB mount AC/DC modules (E.g. Meanwell and Myrra) which only consume 75mW at no load. You may be able to do better still with a bit of searching.

]]>https://forum.fedi.dk/post/https://mastodon.scot/users/GrahamCampbell/statuses/116776731107959514https://forum.fedi.dk/post/https://mastodon.scot/users/GrahamCampbell/statuses/116776731107959514Fri, 19 Jun 2026 12:18:27 GMT