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Forum Index : Electronics : Neat power supply for your 5v projects.

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Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5004
Posted: 12:45am 19 May 2022
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While at my local Bunnings a few weeks ago I picked up a few cheap 1 amp USB power supplies for another project. Once home I discovered one had been squashed, so decided to open it up, it was only $8. Circuit board was OK, so I wondered how low a input voltage it would accept and still provide a stable 5v output.

I'm always on the lookout for a power supply to convert 48v to 5v for off grid projects. I've tried a few buck converters from ebay, but these have a max input voltage of 60v, and I've blown a few when the battery bank was in equalisation. I've also tried a few odd charging wall warts for various gadgets, but these cut out when the input voltage drops below 60 to 70v.

This time I got lucky. This charger would work all the way down to 25v, and still provide 5.1v at 1 amp!

Bunnings also have a 2.4A model, for like $12. I bought one and pulled it apart. Better circuit than the 1A model, and also worked down to 25v.

Here is the 2.4a model....



And these are the two circuit boards, 2.4A and 1A....



For the price, its a real bargain. I'm using one of these in a new solar charger I've been working on based on a ESP32 Dev board. Its supplied by the battery (48 to 58v ) and provides 5.1v for the controller and associated stuff....



Glenn
The best time to plant a tree was twenty years ago, the second best time is right now.
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Haxby

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Joined: 07/07/2008
Location: Australia
Posts: 417
Posted: 06:09am 19 May 2022
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Warp put me on to the benefits of little switch mode power supplies (similar to this) a year or 2 ago.

They are amazing, and are the answer to many problems.

I use them for isolated high/low side gate drives as well as microprocessor projects.

If the marketing guys marketed them as being useful for DC applications, they'd sell a lot more.

I use the 3w Hi-Link ones from Ali express. Namely HLK-pm01, PM05, PM15, etc for 3.3v, 5v, 9v, 12v, 15v, and 24v.

No load power consumption I measured to be 100mW per module. And cost is $4 Inc shipping once over the 10 piece mark.
 
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