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Almost every technical fact in that post is wrong. - The LiIon batteries in phones cannot be charged to 5V. going above 3.7v or 4.2V (depending on battery chem
by theamk 4y ago
Almost every technical fact in that post is wrong.
- The LiIon batteries in phones cannot be charged to 5V. going above 3.7v or 4.2V (depending on battery chemistry) will permanently damage battery and/or will catch it on fire.
- If the battery's internal resistance is 1 ohm, it means it is very bad and should be thrown away. A good battery's internal resistance is 0.05 - 0.001 ohm range.
- Because of that, when charging batteries, you cannot connect it to power adapter directly -- with internal resistance that low, it will try to draw tens of amperes and will overload power adapter and/or overhead and catch fire.
- That's why cell phone has a complex charger chip, which regulates input voltage into whatever voltage/current is required for battery. In most phones it uses DC/DC convertor for higher efficiency/less heat dissipation and has temperature sensor to prevent battery overheating.
- This means all the graphs in the post are junk. (And in the retrospect, it is kinda clear... the second one says 5A / 25W if charging a fully discharged phone. As many adapters are only rated 1-2 amps and cables have similar rating, having this current will destroy the power adapter and melt the cable. And many people charged the phone from 0% before, many times, and there were no significant heating compared to say charging from 40%.