[ELI5] How do “OEM replacement” batteries exist for a device that is several years discontinued? And do they genuinely work better than the battery they are replacing?

Question

I bought a used $20 Samsung Galaxy J7 (2015) since the screen looked to be in perfect condition. I do not know if the seller replaced the battery, but even so, how would a “brand new” battery from 2015 be any better than the current battery inside?

In: Technology

Answer 1

Batteries are pretty simple devices. They have pins that output (and for rechargeable batteries, take in) power and a size they are, and if you can match those the battery will work in a device. Batteries rely on chemistry that means they slowly degrade over time, and faster with temperature changes and charge/discharge cycles. A new battery will generally perform rather better then an old battery. A new old stock battery, if it’s been stored in a climate controlled warehouse, will generally be better then a battery that has been used in a cell phone or tablet.

Sometimes, if there’s enough demand, a factory may keep producing batteries compatible for an older device when support has ended by the manufacturer. If the batteries are up to the same quality standard these OEM batteries are a good replacement option for someone that wants to keep using an old device and has found the battery performance poor.