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What is the specific unsafe condition are you worried about? I don’t know everything but I did evaluate consumer tech for Underwriters Laboratories to IEC 6095

by xnyan 6y ago

What is the specific unsafe condition are you worried about? I don’t know everything but I did evaluate consumer tech for Underwriters Laboratories to IEC 60950 and 62358. I think your caution is commendable but nothing you’ve described is inherently wrong. USB is just a connector. When the product said it needs 5w (I assume you mean 1A @ 4.8-5.1Vdc) by itself means nothing without more information. One really obvious point, did the instructions say it’s a) dangerous with a power supply that can’t provide 1A or b) not/less functional without the 1a supply? If they were not specific, I’m happy to easy your mind - it was the latter.

csnover 6y ago
The specific unsafe condition I am worried about is that the power management electronics lack any sort of fault protection, and this ends up causing a shock, burn, or fire. I have a hard time imagining a situation where a wearable with a USB charging port is designed so cheaply that it only works with specific USB chargers, but still includes over-temp, over-volt, over-current, etc. protection. Needless to say, there is not even a suggestion of this thing being either UL or USB-IF certified.
segfaultbuserr 6y ago
> did the instructions say it’s a) dangerous with a power supply that can’t provide 1A or b) not/less functional without the 1a supply? To me, the real red flag is: what happens when you plug it into an 3 A USB charger? Being a constant voltage supply, the load should only draw as much current as needed, and it should work with no problems (which is the usual expectation of 90% of consumer electronics with a USB port). The warning of "only use 1 A charger" notice is suspicious because it may suggest that the product doesn't include any internal overcurrent protection by itself (like a $0.1 polyfuse), and solely depends on the current limiting of the USB charger for its safety. While it's possible that it's not inherently wrong, but it's certainly a bad design practice.

by xnyan 6y ago

csnover 6y ago

The specific unsafe condition I am worried about is that the power management electronics lack any sort of fault protection, and this ends up causing a shock, burn, or fire. I have a hard time imagining a situation where a wearable with a USB charging port is designed so cheaply that it only works with specific USB chargers, but still includes over-temp, over-volt, over-current, etc. protection. Needless to say, there is not even a suggestion of this thing being either UL or USB-IF certified.

segfaultbuserr 6y ago

> did the instructions say it’s a) dangerous with a power supply that can’t provide 1A or b) not/less functional without the 1a supply? To me, the real red flag is: what happens when you plug it into an 3 A USB charger? Being a constant voltage supply, the load should only draw as much current as needed, and it should work with no problems (which is the usual expectation of 90% of consumer electronics with a USB port). The warning of "only use 1 A charger" notice is suspicious because it may suggest that the product doesn't include any internal overcurrent protection by itself (like a $0.1 polyfuse), and solely depends on the current limiting of the USB charger for its safety. While it's possible that it's not inherently wrong, but it's certainly a bad design practice.