Hello  friend 
It's me Becca , hope this email find you and your family well ;)
as a repairer ,we all know that a battery after used for 2 years ,will happen many problems ,like Power down fast,Low battery health etc.
That's because the batttery has recycle time restriction ,so how can you choose a 0 complain battery ?
1.the battery u bought from your local wholesaler also from china 
  • What is the most important part for the battery? 
  • Why battery  power drop fast after full charge? 
  • If your battery with health state in iOS 14.3?
Battery cell:

There are different brand like ATL, WK and so on. Now the best one is ATL, which also one of the supplier for Apple.

IPhone 6G cheap battery capacity is about 1000-1200m/Ah, the cycle time is about 100-200times. But the for ATL cell, it can the same as the original battery, the cycle time can reach to 500-700 times. 
2:Protection board and flex (PCB)
There have IC chip on the PCB, also with different brand like TI/ZY. The function of IC its detect the voltage and galvanic current. Some battery with dual IC and some is single one. what's dual IC mean?  when the voltage higher/lower the fixed value the it will cut off the MOS conductor automatic, to protect the battery cell.  another IC it's for galvanic current. 
Dual IC protection design ensure the safety and extend the battery's life.
About the iOS 14.3, BIZBEE iphone 5-11 Pro Max  battery with battery health state /battery percentage.
we offer the valid CE and RoHS certification for all battery, it will without any other customs issue. For the battery with logo, we also package carefully to cover the logo.
Bizbee offer your best solution to your business. 

battry from 30pcs for iphone 6 ----3.8$
battry from 30pcs for iphone 7/8 ----4.3$
if you have any needs or problems ,plz feel free to contact ~
purchasing link here
Welcome to contact Becca for more details,my WHATSAPP :+8615797875928
Best Regards!

Have a lovely day!


Becca
Area Manager 

Facebook:https://www.facebook.com/beccabizbee
Whatsapp:https://api.whatsapp.com/send?phone=008615797875928
Ins:https://www.instagram.com/beccawangbizbee