Was probably nothing with life ....
Kraftmax battery with 4500mAh for iRobot Roomba 500/520/540/560 - 14.4V / Ni-MH - brand cells in professional quality for maximum power and long life (Electronics) 1
Kraftmax battery with 4500mAh for iRobot Roomba 500/520/540/560 - 14.4V / Ni-MH - brand cells in professional quality for maximum power and long life (Electronics)