Low Cost Battery Charger Circuit

Posted by Micro System

on Monday, September 27, 2010

This is a circuit for the low cost universal charger circuit diagram for NiCD – NiMH batteries. This battery charger circuit is ideal for car use. It has ability to transform a mains adapter in to a charger . This one can be used to charge cellular phone, toys, portables, video batteries, MP3 players. An LED is located in circuit to indicate charging. This is the figure of the circuit;

 

Before building the circuit, you must determinate how much current will be used to charge the battery or battery pack. It is advisable to charge the battery with a current that is 10 times smaller then the battery capacity, and to charge it for about 15 hours. If you double the charge current, then you can charge the battery in half the time. Charge current selection chart is located in diagram.

Battery Charger Circuit with Constant Current

Posted by Micro System

on Tuesday, September 14, 2010

This is a circuit for battery charger circuit. In this circuit, the battery is charged with a constant current that is generally one-tenth of the battery capacity in ampere-hours. This constant-current battery charger circuit is divided into three sections: constant current source, overcharge protection and deep-discharge protection sections. This is the figure of the circuit;

R2 and T1 limit the charging current if something fails or battery terminals get short-circuited accidentally. To set a charging current, while a multi meter is connected in series with the battery and source supply is present, adjust potentiometer VR1 slowly until the charging current reaches its required value.

Adjust VR2 when the battery is fully charged (say, 13.5V in case of a 12V battery) so that VGS of T5 is set to zero and hence charging current stops flowing to the battery. LED1 glows to indicate that the battery is fully charged. When LED1 glows, the internal LED of the opto coupler also glows and the internal transistor conducts. As a result, gate-source voltage (VGS) of MOSFET T5 becomes zero and charging stops. If the battery terminal voltage drops to, say, 11V in case of a 12V battery, adjust potentiometer VR3 such that transistor T3 is cut-off and T4 conducts. LED2 will glow to indicate that the battery voltage is low. Values of zener diodes ZD1 and ZD2 will be the same for 6V, 9V and 12V batteries. For other voltages, you need to suitably change the values of ZD1 and ZD2. Charging current provided by this circuit is 1 mA to 1 A, and no heat-sink is required for T5. If the maximum charging current required is 5A, put another LM236-5 in series with diode D2, change the value of R11 to 1 kilo-ohm, replace D1 with two SB560 devices in parallel and provide a good heat-sink for MOSFET T1. TO-220 package of IRF540 can handle up to 50W.

NiCad Battery Charger Circuit

Posted by Micro System

on Friday, July 23, 2010

This is a design circuit for a charger circuit. This circuit can be used for Ni-Cad battery. This circuit is built using MOSFET. This is the figure of the circuit;


This array charger ambit is advised for recharging NiCad batteries based on an AC-powered accepted antecedent method. It can crank out as abundant as 1 amp and can be adapted to go alike college by allotment altered accessories for Q1. Since this ambit uses AC band voltages and currents, amuse exercise acute attention during assembly, turn-on, and test. NiCAD batteries accept a accommodation blueprint alleged milli amp-hours. This amount alleged “C” is a measurement of how abundant absolute accepted they can accommodate in one hour. Milli amp-hours is addition way to accurate the activity independent in the battery. To recharge a NiCAD array conservatively, it is accepted convenance to pump a accepted of 0.1 C into the anode or absolute terminal for about 12 hours. Therefore, if you had a D-size NiCAD with a accommodation of 4000mAh, you would appetite to allegation it at 400mA for about 12 hours. Addition advantage of this charging address is that it is affable on batteries and doesn’t account them to lose accommodation as bound as the fast allegation techniques. The achievement accepted of this array charger ambit is controlled by the accretion of the bandgap advertence diode and the base-emitter alliance of the PNP transistor. The PNP transistor provides abrogating acknowledgment to the aboideau of the MOSFET. As acclaimed in the schematic, the batteries actuality answerable can accept a absolute of 12V which is agnate to about 8 NiCAD’s in series.