Dear EC,
Due to battery to use for the generator for backup power system electrical components such as elevators, lighting, centralized, etc.the battery can't be fully changed after recharged.These battery was changed on Sep 30,2013 (Normally battery last for 2 years.)
Please find attached comparison file to replace 4 Batteries at Tower A&B. We recomend OA Sales & Service Co.,Ltd.
For your approval consideration.