Amazon.com: 2600mAh Replacement Li-Ion Battery for iRobot Roomba e and i Series i7 7150 i7+ 7550 i6 6150 i6+ 6550 i3 3150 i3+ 3550 i4 4150 i4+ 4550 e5 e515020 e5152 e6
Amazon.com: 3200mAh i7 Lithium ion Replacement Battery for Irobot Roomba i7 7150 i7+ 7550 e5 e5152 e5154 e6 i3 3150 i3+ 3550 i4 4150 i4+ and More e/i Series Vacuum-4624864, ABL-D1 -BURFLO :
Amazon.com: KUNLUN 3200mAh i7 Battery Replacement Compatible with iRobot Roomba e and i Series i7+ 7150 7550 i3 3150 i3+ 3550 i4 4150 i4+ 4624864 ABL-D1 Lithium Ion Battery Extended Life : Home & Kitchen