12V Battery charger circuit

Published:2012/9/24 4:13:00 Author:muriel | Keyword: 12V, Battery charger | From:SeekIC

This battery charger circuit can be used to charge one or more batteries with the total nominal voltage of 12 V, meaning ten NiCd battery or six 2 V lead acid. The circuit is pretty small and can be built in a housing network adapter. The incorect usage is impossible: connecting the batteries with reverse polarity, shortcircuit of the output terminals or power loss have no impact on the charger or battery.We can use a transformer with 18 V on the secondary and then using a diode bridge to rectify the 18V ac voltage we get 22V dc on C1. The completely discharged batteries are charged at the begining with a 6 mA current thru R2-D2 and R4-R6-D1. One the bat. have reached 0.3 – 0.5 V, the base-emitter voltage of T1 is high enough to bring the transistor in conduction. Green LED D4 is used as an charging indicator and opens T1.There is a 60 mA current flowing thru R5-R6, this means that the charging of a 500 mAh NiCd battery will take 12 hours. If the battery is connected with reversed polarity or there is a shortcircuit, the power transistor T1 remains blocked and the charging current can not exceed 6 – 12 mA. The current draw at maximum load is around 80 mA. Battery charger circuit schematic Battery charger PCB Layout Components ListR1 = R2 = 10KR3 = 1KR4 = 5.6KR5 = R6 = 12Ω C1 = 1nFC2 = 220µF / 35V D1 = 1N4001D2 = D3 = 1N4148D4 = green LED T1 = BD140T2 = BC546? 12 Responses to “12V Battery charger circuit”



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Power_Supply_Circuit/Battery_Charger/12V_Battery_charger_circuit.html

Print this Page | Comments | Reading(3)