How long does the VDC take to recharge after a full discharge?
The recharge time after a complete discharge is factory adjustable per application requirement. For UPS applications the recharge time default is approximately 12 minutes. The current is limited by the current available from the UPS rectifier. After an outage, the UPS is typically fed by the stand-by emergency diesel generator. As a result the recharge current is set for approximately a 12 minute re-charge to avoid overstressing the diesel engine. Even if the utility returns, the diesel will typically power the UPS for 10 to 15 minutes to assure a stable utility supply. If the UPS and diesel engine are properly sized, the recharge current can be increased to reduce the time needed to re-charge. While recharging, if another event were to occur, the VDC will provide whatever energy is available instantaneously even though it is not fully charged.
