I have two 10,000 mAh batteries from an original Xiaomi 20,000 mAh power bank. My power bank was broken, but both batteries are in good condition; I have checked the battery capacity myself (you can see in the pictures). The actual total capacity is still 11,500 mAh. When there was no electricity at home for a few days, I connected these two to my Mini UPS and ran a 12V 1A router and a 12V .5A ONU. I got about 9-10 hours of backup.