Keep your device unplugged for longer with the 9 cell thinkpad battery 70 the average run time is 94 watt hours and the battery can be recharged with the thinkpad external battery charger 40y7625 each power source uses lithium ion technology and can be used as replacement for damaged system batteries or as a convenient spare the battery is compatible with t410 t420 t430 t510 t520 t530 w510 w520 w530 l410 l412 l420 l421 l430 l510 l512 l520 and l530 systems battery life