New batteries won't lose capacity over time. A lot of "new" batteries are just knockoffs, but there's no way of knowing without opening them.
If you want good aftermarket batteries, KingSener has a solid reputation. Only go for aftermarket batteries that are upfront about being aftermarket and are open about the cells they use and well reviewed, or for sealed Lenovo batteries in original packaging.
I recently bought a brand new, sealed 72Wh original battery. It sat sealed for so long the batteries went down below 3.1V per cell and the pack locked itself. Looking at the self discharge curves I'd expect this to be the case for any actually new battery.
To make it work I had to open the battery and use a specialized charger to give it 0.1A of current until it got to 3.3V per cell, and I then programmed it to charge at 6A, after which the battery pack decided to start up.
Thanks. I’ll try that brand. I buy mine from Encompass, the official seller of Lenovo batteries. So they shouldn’t be knockoffs, nor unsealed. But, one battery went from 90% health down to 30% in the course of six months. And they’re not cheap!
If you want good aftermarket batteries, KingSener has a solid reputation. Only go for aftermarket batteries that are upfront about being aftermarket and are open about the cells they use and well reviewed, or for sealed Lenovo batteries in original packaging.
I recently bought a brand new, sealed 72Wh original battery. It sat sealed for so long the batteries went down below 3.1V per cell and the pack locked itself. Looking at the self discharge curves I'd expect this to be the case for any actually new battery.
To make it work I had to open the battery and use a specialized charger to give it 0.1A of current until it got to 3.3V per cell, and I then programmed it to charge at 6A, after which the battery pack decided to start up.