My UPS is not charging the battery to full.
So I watched a lot of YouTube videos and guides on using lithium batteries with UPS units as replacements for lead acid batteries. Which made me buy 2 new APC units with 2 new sets of lithium batteries to try out.
At first the APC units I bought from Amazon were defective, showed a massive load on them when nothing was plugged in. APC replaced them immediately with no issues.
The new ones I got I then pulled out the lead acid batteries and put in a new set of 12v 10ah lifepo4 batteries. Ran a 35w load on it and only got 1 hour and 40 mins of runtime.
So I figured it wasn’t fully charged, and waited 48 hours before my next test, this time it lasted 2 hours and 30 mins, still way below the 6+ hours it should be getting according to the math.
So I bought a different brand of batteries to test to see if it was the battery itself. After a few days of charging I checked both batteries voltage and both were at 26.5v so each battery was at 13.25v, the minimum and maximum voltage for these batteries are 11.4/14.8v so these were not fully charged, on both units.
Whats going on, and how do I fix this?
APC Unit: BR1500MS2
Batteries: MightyMax 12v 10AH LifePO4 Batteries, ECO-Worthy 12v 10AH LifePO4 Batteries