Which are trustworthy brands for a simple USB wall charger?

[robosensor]

If safety is on the first place you can make your own power supply using miniature transformers like this (lower half of PCB):

Such transformers are very small for low-power nodes:

UPD: link to the topic: https://forum.mysensors.org/topic/6259/encapsulated-transformers-instead-of-traditional-switching-power-supplies-like-hi-link

[NeverDie]

Maybe I worry too much. Provided that as a USB charger's plastic housing isn't combustible, then any failure would be "contained"?

[mfalkvidd]

@NeverDie yes, as long as it doesn't send too much voltage on the 5V output (and fries whatever you have connected)

[robosensor]

@NeverDie you can just google for images for "exploded/burned phone charger"

Just an example:

[NeverDie]

Yeah, your example is the sort of thing I want to avoid. From what I've read, the electrolyte in capacitors can boil off over time, creating a kind of time bomb.

[sundberg84]

@NeverDie - I have also posted pictures in this forum and other forum about personal issues with "genuine" (fake!) iphone/samsung charger. Just a search on ali/ebay makes it impossible with that amount of results to know which one is good vs bad... i guess it some way you pay more for good.

My guess is that we are going to see more fires... I watched a morningshow here in Sweden some time ago and it was considered safe so far with the chargers (13 fires / year) verses stove fires (1500+/year) but the last linked charger (samsung) was bought at a market here in sweden in a nice packaging sold as a genuine... it was not so i guess the market is getting quite flooded with fake ones.

My second guess is as the charger is safer using it as just a charger than putting a unknown DIY load as well. Might be the work fine charging phones but what happens when you add to much load to them?

[gohan]

As usual it is always the problem of attaching to mains a supposedly certified shitty power adapter or make your own high quality and safe adapter but not certified. Probably phone chargers are just not designed to be used 24/7

[NeverDie]

@gohan said in Which are trustworthy brands for a simple USB wall charger?:

Probably phone chargers are just not designed to be used 24/7

No, of course they are. Good ones anyway.

[NeverDie]

@sundberg84 said in Which are trustworthy brands for a simple USB wall charger?:

it was considered safe so far with the chargers (13 fires / year) verses stove fires (1500+/year)

I suppose one could monitor the temperature of the charger since, after all, it would be used to power a sensor node anyway. Maybe that would give some advance warning if things are heading badly before it goes catastrophic?

[robosensor]

Seems like this is offtopic, but there are good meanwell power supplies designed to run 24x7, like this:

http://www.meanwell.com/webapp/product/search.aspx?prod=DR-15 (MTBF 1.1M hours)

Or even something like this:
http://www.meanwell.com/webapp/product/search.aspx?prod=PM-05 (MTBF 1.5M hours) and so on

I used long time this NFM-05-5 power supplies, very good, no problems at all:
http://www.meanwell.com/webapp/product/search.aspx?prod=NFM-05

[gohan]

@robosensor nice, but not very handy as a wall charger.

[sundberg84]

one could monitor the temperature

@NeverDie - this is the exact approach I have in my In wall AC/DC nodes.
https://www.openhardware.io/view/13/In-Wall-ACDC-Pcb-for-MySensors

[NeverDie]

If you've guys have never seen any of the videos from:
https://www.youtube.com/user/bigclivedotcom/videos
many of them are quite entertaining. I think he may have been a Scottish electrician or something. He routinely buys things from the pound shop, tears them down, and often shows them to be "deathtraps," especially for mains connected devices.

[gohan]

most cheap stuff is potentially a death trap if it is mains powered :D

[NeverDie]

Noticing now that at least some of them claim to offer various protections:

https://www.aliexpress.com/item/LED-Display-3-USB-Charger-ROCK-Universal-Mobile-Phone-USB-Charger-Fast-Charging-Wall-Charger-For/32832813133.html

So, what would be the cheapest one but offering good protections?

[gohan]

I wonder how they achieve over charge protection :anguished:

[NeverDie]

I guess the way to do it would be if someone credible like Dave Jones did a tear down and vetted a particular USB charger. Then get that make and model. Ignoring counterfeits, maybe then it would be deem-able as "safe."

[mfalkvidd]

When I need multiple ports, I use the IKEA chargers. Reasons:

• They are the cheapest per mA and port that I can buy locally
• They are a big brand with a reputation to protect
• bigclivedotcom has done a teardown and deemed it safe

[NeverDie]

@mfalkvidd Good find! I also just now found a teardown by bigclive for the ~$1 usb wall chargers that I was thinking of getting:
https://www.youtube.com/watch?v=bNoGCdX1IdQ
and it has convinced me that it would have been a mistake. So, I guess around $7.50 or more is what it's going to take for a decent, safe quality usb charger. So, suddenly batteries start to look like a reasonable alternative, whereas before I wouldn't have thought so.

[gohan]

battery or wall charger it is a choice that depends on the kind of sensors you want to use :)