4 ms·
How much power is lost with all of those dumb little DC bricks all over the place right now?
by rachelbythebay 14y ago
How much power is lost with all of those dumb little DC bricks all over the place right now?
- nitrogen 14y agoWith PoE you lose the power three times instead of just once. You have an AC-to-DC brick for the PoE injector (or similar inside of a PoE-enabled switch), then resistive loss on the cable (about 2.4W lost for every 12.5W that reaches the device[0]), then another DC-to-DC converter at the device itself. Now, don't get me wrong. I really like PoE, and would love to have something similar for lighting, but PoE itself can't handle the current required for primary lighting. How much power is lost with all of those dumb little DC bricks all over the place right now? According to http://what-if.xkcd.com/35/ http://what-if.xkcd.com/35/, as a rule of thumb, any DC transformer that's not warm to the touch is wasting less than a penny of electricity per day, and a cellphone charger, if not warm to the touch, less than a penny per year. [0] http://www.connect802.com/ethernet.htm http://www.connect802.com/ethernet.htm