APC SMART-UPS DLA1500 Replacement with 2 x 12V 18AH SigmasTek Batteries | eBay
Amazon.com: APC Dell SmartUPS 1500VA USB DLA1500 12V 18Ah UPS Battery - This is an AJC Brand Replacement : Electronics
Amazon.com: RBC7-UPC Replacement Battery for APC Smart-UPS SU1400, SUA1500, SUA750XL, SUA1000XL, SU1400NET, SU1000XLNET - Scroll Down for The Complete List of Compatible Models : Electronics