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Re:New 10.3″ Waveshare E Ink Monitor by jwr on Thursday January 16, 2020 @04:44AM (#22063011)
5V/3A (15W) — that sounds like a LOT for an e-ink display!
Re:New 10.3″ Waveshare E Ink Monitor by VLM on Thursday January 16, 2020 @08:06AM (#22064089)
A popular amount of power for USB type device chargers, so economy of scale applies.

Economy of scale makes weird pricing happen.

Right now on digikey you can buy a "SWI25-12-E-P5" 25 watt PSU for $11.95, or a "KTPS12-12010WA-VI-P1" 12 watt PSU for $12.21. Both are wall mount class 2 supplies, level 2 efficiency standards, even the same connector. The cheaper one has a longer cord, LOL, as yet another weird example of economies of scale.

If your application requires 10 watts, a 25 watt supply will quite happily provide 10 watts and run extremely cool for a long time compared to a 12 watt supply being asked to provide 10 watts.

I will admit that one mfgr chased safety approvals for euro countries and the other chased safety approvals for USA/Asian countries, but for hobbyist one off purposes, something that passes TUV/CE is approximately as good as something that passed UL, and if you want to sell commercially in the US its usually a paperwork transaction to cross approve something. A bigger problem is X% where X is pretty large, of chinese mgfr equipment has fake safety marks. So for hobbyist purposes you're far safer using a genuine TUV approved supply in the US than graymarket gear with a fake UL mark. So there are minor differences. It would be non-trivial to design something that could pass TUV but fail UL, although someone out there has probably succeeded in the past.

The real world market is not magically 100% efficient, so you can absolutely pay 26 cents more for a supply with a shorter cable and lower power output.

Re:New 10.3″ Waveshare E Ink Monitor by r3drock on Thursday January 16, 2020 @05:07AM (#22063150)
It only uses electricity when it refreshes, so it does not seem that high.
Re:New 10.3″ Waveshare E Ink Monitor by fnord77 on Thursday January 16, 2020 @06:40AM (#22063615)
if you're typing something, wouldn't be constantly refreshing?
Re:New 10.3″ Waveshare E Ink Monitor by rustybolt on Thursday January 16, 2020 @06:53AM (#22063679)
Most e-ink displays only refresh sections. So if you type a letter, it really only draws the letter. If you scroll however, the whole screen needs to be updated.
Re:New 10.3″ Waveshare E Ink Monitor by agumonkey on Thursday January 16, 2020 @09:13AM (#22064642)
unless the software stack has a degraded mode for power saving