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How do I buy quality external power supplies ("Adapter"/"Wall wart") from China?
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SmallCog:
Basic options:

1) Buy from online marketplaces such as ebay/ali/bangood/wish etc. and roll the dice that you'll get what you ordered and it will be safe

2) Buy the above with the skills/experience/knowledge to open the device, assess its safety, and either make the appropriate alterations or dispose of it and try again.

3) Buy from a reputable retailer that does the quality checks for you, and pay a premium.

There's no magic trick to buying option 1 and getting option 3. Even if you think you've received an option 3 device for $2 posted from China it may well be a counterfeit (look at all the counterfeit apple charges available) or from a batch that have failed some sort of quality inspection.

My go-to suggestion for anything low power DC is to make it suitable for USB. In the case of your friends device they could incorporate a small boost module in their design and fit a micro-USB socket on their device and use it with a quality brand name adapter - either bought new or surplus from an old phone or something.
Karel:

--- Quote from: SmallCog on February 21, 2022, 02:18:26 am ---
My go-to suggestion for anything low power DC is to make it suitable for USB. In the case of your friends device they could incorporate a small boost module in their design and fit a micro-USB socket on their device and use it with a quality brand name adapter - either bought new or surplus from an old phone or something.

--- End quote ---

You can't draw more than 100 mA from USB except when you include some intelligence and even then it's not guaranteed
you can draw up to the max. 500 mA.
John_doe:

--- Quote from: BeBuLamar on February 20, 2022, 03:51:18 pm ---How much is sane price? I would think $20 is still a sane price.

--- End quote ---
Well, I guess that for an adapter of, lets say, 30W, $20 including shipping sounds like a fair price. Not a great price, just a fair one. But even that price I was unable to find.



--- Quote from: Karel on February 20, 2022, 03:56:44 pm ---I hope you'll find an acceptable alternative or workaround.

--- End quote ---
Thank you.



--- Quote from: janoc on February 20, 2022, 04:09:24 pm ---$20 (or rather 20€) is pretty much the standard shipping price even within EU if you order from Farnell or Mouser for less than some minimal value (50€-ish).

So, OP, you are certainly not in what I would call a "small" and/or "isolated" country! Those are normal prices.

--- End quote ---
I wasn't suggesting as much. My gripe is the lack of trustworthy local sources.
But since you mentioned it, IMHO if Farnell or Mouser ship within Europe for $20 then they are the exception. I have seen websites that send their goods for cheaper. Also, I tried it now, and the lowest possible shipping quote was $28:




--- Quote from: janoc on February 20, 2022, 04:09:24 pm ---And when it comes to ordering mains stuff from China - $20 shipping for a good, certified wall wart is too expensive but I wonder whether replacing whatever a crappy, poorly designed adapter from AliExpress has blown up will be cheaper? And that's still the good case, there have been plenty of fires and even electrocutions documented because of crappy wall warts.

Especially so when the person in question has no clue how to spot dangerous equipment? Hint, you can't do it from pictures on a web site, so your question doesn't have an answer - there is no way to buy "quality power supplies from China" unless you are a business and/or do a lot of research and get into long term business relationship with a trusted supplier, including inspecting the goods. I.e. pretty much out of the question for buying a one-off part.

When it comes to anything mains powered from places like AliExpress or Banggood, the first thing to do is to always take it apart and inspect. And fix whatever needs fixing - missing earth connection, poor insulation, lack of fuses ... Often even tossing the power supply out and replacing it with a known good one. If you can't or are not willing to do that, you are playing Russian roulette with your equipment, safety of your house and anyone living in it and really should buy a power supply from a distributor who has to sell only certified and tested equipment. Even if it costs more.

--- End quote ---
I agree with almost everything you said, but I thought I'd try and ask. Maybe someone knows better. Also, specifically in my current situation, the problem was not so much as finding a cheap adapter, but finding ANY adapter with the non standard value of 10V.

The one issue I disagree on, is USB power supplies (colloquially called "USB Chargers") - These CAN be bought from China for dirt cheap and still be of reasonable quality. There are people who review such chargers regularly, such as Henrik K. Jensen (lygte-info.dk). And the companies behind brands like Anker, Blitzwolf, Ugreen and Baseus do not change model internals, so if one model is proven to be safe, you can buy it with no worries.

Oh, and as for Mr. Mitchell, I watch his videos in order and right now I'm about two weeks behind, so I'll watch this video when I get to it. No spoilers!!




--- Quote from: SmallCog on February 21, 2022, 02:18:26 am ---In the case of your friends device they could incorporate a small boost module in their design and fit a micro-USB socket on their device and use it with a quality brand name adapter - either bought new or surplus from an old phone or something.

--- End quote ---
Yes, I have decided to do something of this sort. Thank you.



--- Quote from: Karel on February 21, 2022, 07:20:49 am ---You can't draw more than 100 mA from USB except when you include some intelligence and even then it's not guaranteed
you can draw up to the max. 500 mA.

--- End quote ---
That's not true for USB "Chargers" with USB-A ports. Actually, I'm not even sure it's true for computers anymore. I have brand name 100% genuine chargers and I don't even have to short D+ to D- (as per BC v1.2) to get 2 amps from them.
wraper:

--- Quote from: SmallCog on February 21, 2022, 02:18:26 am ---Basic options:

1) Buy from online marketplaces such as ebay/ali/bangood/wish etc. and roll the dice that you'll get what you ordered and it will be safe

2) Buy the above with the skills/experience/knowledge to open the device, assess its safety, and either make the appropriate alterations or dispose of it and try again.

--- End quote ---
Unfortunately that is not enough. A lot of them may look OK on a first glance, however transformer may easily lack any serious insulation or QC even if construction is somewhat decent. Only Hi-pot test will show if its electrically safe or not.
Karel:

--- Quote from: John_doe on February 21, 2022, 10:38:32 am ---
--- Quote from: Karel on February 21, 2022, 07:20:49 am ---You can't draw more than 100 mA from USB except when you include some intelligence and even then it's not guaranteed
you can draw up to the max. 500 mA.

--- End quote ---
That's not true for USB "Chargers" with USB-A ports. Actually, I'm not even sure it's true for computers anymore. I have brand name 100% genuine chargers and I don't even have to short D+ to D- (as per BC v1.2) to get 2 amps from them.

--- End quote ---

You are right, I forgot we were talking about (wall)chargers. But for pc's I believe it's still true.
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