10.8v 32wh New Original Laptop Ultrabay Battery 45n1040 45n1041 For Lenovo Thinkpad T420s T410s T430s 51j0508 51j0507 57y4536 - Laptop Batteries - AliExpress
I figured out how to not hate a t420s! (i7+dgpu heat monster) (new main& ultrabay batteries=8+ hours, 1sata 860evo 1tb, 1msata 128gb, tf8 thermal paste) Now it's actually resembling a T series! :