How do I provide a stable power supply for a device that will be staying on permanently? I have a "Cheap Yellow Display" Esp32 and if I plug it into a cellphone charger it eventually freaks out the program. If I plug it into a USB power bank/battery and have the cellphone charger connected it lasts longer before the program crashes. I know it's the charger because when i turn off the power the screen goes off for a second then comes back on, I imagine it is reconnecting to the USB bank. If I simply plug it in a decent USB power bank it can run until the battery goes flat.
Something like https://www.digikey.co.za/en/products/detail/mean-well-usa-inc./RS-25-5/7706180?
This is 5V / 5A. You can get more powerful ones if needed.
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Baie dankie 
Both cellphone chargers and power banks are designed to charge cellphones. Many of them will cut off if they decide whatever is connected to them is fully charged.
Use something described as a power supply, not a charger, with a 5V output and at least 20% more current capacity than your circuit needs.
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I run many ESP devices from generic USB phone chargers. I use 5V/1A chargers; I doubt they will really supply 1A, but an ESP32 will draw maybe half that with WiFi on, max. So maybe just get a somewhat better phone charger and try again.
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Thanks, I've tried two different chargers with the same results.
So try 3rd one. Some original Samsung charger would be good choice. If that Esp board has usb port and doesn't work with any charger, the manufacturer has a big problem with refunds.
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…or try using a real power supply.
It doesn’t have to be big or expensive, just designed to be a power supply.
(If that’s your problem!)
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Most power banks turn off the output when there is not enough power drain to save battery. But did you really see a mains powered cell phone charger (or anything else) with such behavior? That would increase complexity (read: cost) without any benefit the user might notice.
Well, there's the 130W charger for my DELL laptop. I tried to use it to power an RPi 4. Works great for up to about an hour, then cuts the power.
But you are right, I don't think any of the smaller, cheap chargers I have around the house do that. I haven't tested the 30W charger for my smartphone to see what that does.
I am doing some more tests to see if the problem was simply heat related. I previously had my CYD taped to a clear plastic surface inside a junction box so it couldn't dissipate heat so easily. I added some spacers to give it more breathing room and have had it running for 24 hours off a 2.0 A/H USB power bank [It dropped from 100% to 43% in 24 hours just for interest]. I have now changed it over to a cheap USB power supply and will leave it going like that overnight to see how it compares.
That's not a box with live AC in it as well, is it? If so, don't do this. It's bad practice (and disallowed by local codes generally) to mix LV devices and live AC wiring inside the same fixtures and ducts.
I basically had an extension lead going into the enclosure and plugged my power supply into that. Presently I have removed that and have the power supply plugged externally and it just has a long built-in micro-USB cord that I have running into the enclosure. It's been going for about 36 hours now with no issues.
It may seem like it's not an issue but I can assure you it will be if you mix ELV and mains level in the same enclosure.
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Just an honest question with regard to that: How is that different to something like a microwave with a mains feed converting to dc and electronic components inside the same enclosure?
Obvious I would have though however, manufacturers have to follow strict guidelines as to segration and insulation requirements.
In addition, none of the ELV is exposed to the outside of the enclosure.
When you take an ELV conductor out or into a mains enclosure it does not comply and subjects people, most times your kids or family, to your ignorance.
I think you have misunderstood my description. An extension lead, that is used in most households, and a cellphone charger, also used in most households - is actually safer going into an enclosure than it would be not in an enclosure, even though it is pretty safe without it.
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