This was originally posted on APC forums on 8/3/2020
I bought a new RBC7 battery replacement (17Ah, 24V) pack for a Smart-UPS SMT1500I (1500AV, 1050W) with a AP9631 Network Management Card 2. The NMC2 allows me to collect and plot data provided by the UPS.
So I ran tests: the load is a laptop charger and a traditional light bulb and the powerstrip with power monitor says together they peak at 150W.
1) disconnect the input power from the UPS (see attached picture SMT1500i-RBC7-batt)
2) built-in calibration test (see attached picture SMT1500i-RBC7-cal)
Both diagrams clearly show a 20% battery charge drop right when the UPS switches to battery output. After that drop the battery charge decreases linearly.
Is this normal behaviour of a new and freshly charged RBC7 model battery? If that is normal how is the initial charge drop explained?