From the situation described, even if the entire charging process is 3A constant current, it can theoretically only charge less than 16ah of electricity. The battery described in the question is 30ah, so there are several possible situations, 1. . The battery is old or falsely marked and the capacity is not enough 2. There is a problem with the protection board and the protection threshold is too high, causing the power supply to be protected without being released. groups of cells have unbalanced tension. Whatever the reason, the battery core should be tested to determine it.
The acceptable power of the 48V30A battery is 48*30=1440WH. Under normal circumstances, the power reception efficiency of the battery is about 70%. The charger efficiency is calculated at 80%, so the power consumed by a full charge is The battery capacity is approximately:
1440/70%/80%/1000=2.57 kWh
I hope this is useful to you.