How long does a 3kVA UPS take to recharge?

The recharge time for a 3kVA UPS lead acid battery set should be up to 6hours but will be dependent upon the size of the battery (measured in Ah) and the size of the charger (measured in Amps). The longer the runtime, the larger the battery set installed and potentially the longer the recharge time. A rule of thumb is to achieve 80% within 24hours (formula Ah/A=recharge time). Charging in non-linear and so the last 20% can take several hours longer. For extended runtime packs connected to the UPS, the charging capacity can be increased to reduce the recharge time by using a larger charger. This may be installed inside the UPS itself or in the battery extension pack. Note that each externally battery charger will require its own AC power source. Lithium-ion batteries can recharge far quicker and reach 80-100% capacity within 2hours.