operate || Charging
(1)Stand-by / black-up use (Trickle use)
The application load is supplied with power from AC sources in normal state.Stand-by / back-up use is to maintain the battery system at all time so that it can supply power to the load in case the AC inut is disrupted (such as a power failure). The are two methods of charging for this use.

(a)Trickle charge (Compensating charge) Trickle charge In this charge system, The battery is disconnected from the load and kept charge with a small current only for compensating self discharge while AC power is alive, In case of power failure, the battery is automatically connected to the load and battery power is supplied. This system is applied mainly as a spare power source for emergency equipment. In this use. If rapid recovery of the battery after discharge is required, it is necessary to consider the recovery charge with a comparatively large current followed by trickle charge, or alternative measures, While the type and capacity of the battery is determined by the back-up time and the load (current Consumption) during power failure, some reserve power should be taken into account considering such factors as ambient temperature, capability of the charge and depth of discharger.

Trickle charge system model
(Precautions on charging)
1.As the battery continues to be charged over a long period, a small difference in charging voltage may result in a significant difference in the battery life. Therefore, charge voltage should be controlled within a narrow range and with little variation for a long period.
2.As charge characteristics of the battery are dependent on temperature, compensation for temperature variation is required when the battery is used over a broad temperature range, and the system should be designed so that the battery and the charger and kept at the same temperature.

- Float charge
Float system is the system in which the battery and the load are connected in arallel to the rectifier, which should supply a constant-voltage current.

Float charge system model

In the above-illustrated model, out put current of the rectifier is expressed as:1O=1C+1L where 1C is charge current and 1L is load current, Consideration should be given to secure adequate charging because, in fact, load current is not constant but irregular in most cases. In the float system, capacity of the constant-voltage power souce should be more than sufficient against the load. Usually, the rectifier capacity is set at the sum of the normal load current plus the current needed in order to charge the battery.
(Precautions on charging)

1.(a) in constant voltage charging (cycle use): Initial current should be 0.4 CA or smaller (c:rated capacity)
   (b) in V-taper charg control system: Initial current should be 0.8 CA or smaller (c:rated capacity)
   (c) in constant voltage charging (trickle use): Initial current should be 0.15 CA or smaller (c:rated capacity)

2. Relation between standard voltage value in constant voltage charging And temperature is given in the table.
Relation between standard voltage voalue in constant voltage Charging and temperature <<==Prv