24.07.2025 How much energy does it take to charge a phone Phone batteries use 3.7 V DC USB chargers output 5 V DC 230 V AC → 5 V DC conversion efficiency ≈ 0.8 (0.75 – 0.9) 1 2 5 V → 3.7 V conversion efficiency ≈ 0.9 (0.88 – 0.95) 3 Every 1 000 mAh (= 1 Ah) of … more…