Firstpower 5.0Ah 14.4V Compatible with Roomba Battery Replacement R3 Battery 500 600 700 800 900 Series 510 530 531 532 535 536 540 550 552 560 570 580 595 620 650 660 760 770 780 790 800 870 (Amazon Affiliate)
US: https://amzn.to/39RSPFD
Roomba 600 Series Upgrade, Maintenance and Repair: https://youtu.be/RS1z1BAymCY
Lithium Battery (Amazon Affiliate)
US: https://amzn.to/2fT9QW5