27/03/2022
Have you noticed how phones with fast charging tend to have smaller batteries than phones that charge slowly? We did. We even asked manufacturers about it, however, they were pretty tight lipped about the details. So, we decided to do our own research.
We searched through our database for devices from the same maker, that launched around the same time and that have the same dimensions (down to the tenth of a millimeter), but offer different charge speeds. The idea is to remove as many variables as possible. Often times addition of fast charging is the difference between vanilla and Pro models, so it is sold as a premium feature.
How much battery capacity does fast charging “cost”? Based on twelve pairs of devices, the short answer is around 10%. So, one phone may have a 5,000 mAh battery, a nearly identical model with fast charging will have a 4,500 mAh battery. The loss varies by model of course and in general faster charging means less capacity.
Model Battery Charge rate Model Battery Charge rate Battery delta Specs comparison
Xiaomi Redmi Note 11 Pro (China) 5,160 mAh 67W Xiaomi 11i HyperCharge 5G 4,500 mAh 120W -15% Specs
Xiaomi 11i 5,160 mAh 67W Xiaomi 11i HyperCharge 5G 4,500 mAh 120W -15% Specs
vivo Y72 5G 5,000 mAh 18W iQOO Z3 4,400 mAh 55W -14% Specs
Realme 7 (Global) 5,000 mAh 30W Realme Narzo 20 Pro 4,500 mAh 65W -11% Specs
iQOO Z5 5,000 mAh 44W iQOO Neo5 SE 4,500 mAh 55W -11% Specs
Xiaomi Redmi K50 5,500 mAh 67W Xiaomi Redmi K50 Pro 5,000 mAh 120W -10% Specs
Xiaomi Mi 10 5G 4,780 mAh 30W Xiaomi Mi 10 Pro 5G 4,500 mAh 50W -6% Specs
Xiaomi Pad 5 8,720 mAh 33W Xiaomi Pad 5 Pro 8,600 mAh 67W -1% Specs
Xiaomi Redmi Note 9 Pro (India) 5,020 mAh 18W Poco M2 Pro 5,000 mAh 33W 0% Specs
Redmi Note 9 Pro (India) 5,020 mAh 18W Redmi Note 9 Pro 5,020 mAh 30W 0% Specs
Oppo F17 Pro 4,000 mAh 18W Oppo A93 4,015 mAh 30W 0% Specs
Oppo Reno4