APC UPS Pro 550 POWER KINGDOM Battery Replacement - YouTube
Solved: Back-UPS Pro 550 not charging battery when powered on - Communities
Powery GEL battery for UPS APC Power Saving Back-UPS Pro 550 9Ah 12V, 12V, 9Ah/108Wh, Lead-Acid battery, rechargeable, 151mm x 65mm x 94mm, 100% Compatible. New - AliExpress Consumer Electronics
User manual APC Back-UPS 550 (English - 2 pages)
Teardown and operation of an APC Back-UPS RS 550
APC BR700G Back-UPS Pro 700VA 6-outlet Uninterruptible Power Supply (UPS) - Newegg.com
User manual APC Back-UPS 550 (English - 2 pages)
APC Back-UPS ES 550 - UPS - 330 Watt - 550 VA - BE550G - UPS Battery Backups - CDW.com