C-POWER

Charge Methods For C-Power Ni-Cd Batteries

There are several charging methods for rechargeable Ni-Cd and it is important to note that different type of battery systems are suitable for different charging methods. Correct charge and discharge are critical to the cycle life of rechargeable batteries

The charge methods for Ni-Cd batteries can be generally classified into two types according to the purpose for which the batteries are used:

Cycle Use

The battery is repeatedly charged and discharged. This is the most common method for using Ni-Cd batteries.

Standby Use

Power is normally supplied to the load from an AC power supply, and the Ni-Cd battery is used to maintain the power supply to the load in the event that the AC power supply is interrupted.

1. Methods of Charge for Ni-Cd Battery

Use Application	Charge Methods	Charge Time	Charge Control	Notes
For Cycle Use	Standard Charge	15 hours	Semi-constant- current Charge System	-----------
	Quick Charge	6 to 8 hours	Timer-controlled Charge System	-----------
	Rapid Charge	1 to 2 hours	-△V Cut-off Charge System	value of -△V is 10mV-15mV/cell
	Rapid Charge	1 to 2 hours	dT/dt Charge System	0.5℃ -1℃ per 1 minute
For Standby Use	Trickle Charge System	Continuous Charge	-----------------------	at a low rate of 0.03CmA to 0.05CmA

2. Detail Comparison of the Various Charge Systems

Charge system	Cycle Use				Standby Use
Charge system	Semi-constant Current Charge	Timer Controlled Charge	-V Cut-off Charge	dT/dt Cut-off Charge	Trickle Charge
Features	Typical type; Simple; economical	Reliable than Semi-constant current; Relatively simple and economical	Most popular; The extra safety and reliable; Good for battery protection	costs more than the others but overcharge can be avoided; enabling longer life cycle than other charge method; Good for battery protection	Simple and Economical; Applicable to the equipment for continuous long charge
No. of Output Terminals	2	2	2	3	2
Charge Time	15 hours	6 to 8 hours	1 to 2 hours	1 to 2 hours	24 hours or longer
Charge Current	0.1 CmA	0.2 CmA	0.5CmA to 1 CmA	0.5CmA to 1 CmA	frequent charge: 0.05CmA-0.03 CmA
Trickle current	---	---	---	---	frequent charge: 0.05CmA-0.03 CmA
Charge Level at Charge Control	---	Aprox.120%	Aprox. 110% to 120%	Aprox. 100% to 120%	--
Application Examples	Shavers, Cordless Phones, Toys	Cordless Phone, Shavers, Portable equipment	Data Terminals, Camcorder, Wireless equipment	Power Tools, Electric Tools, Cellular Phones	Emergency lights, Guide lights, Memory back-up