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Automatic 12V Battery Charger

Charger can work with gel, AGM and acid 12 V batteries. Led Indicates when battery is fully charged.

Components

C1    -   220uF 25V Electrolytic Capacitor   
D1    -    P600 Diode - 50V 5A or greater rectifier diode
D2    -    1N4004 Diode  
D3    -    5.6V Zener Diode

D4    -    LED

R1,R3 - 330 Ohm 1/4W Resistor   
R2    -    100 Ohm 1/4W Pot   
R4, R5 -82 Ohm 2W Resistor
R7, R8 -82 Ohm 2W Resistor   
R6    -   100 Ohm 1/4W Resistor   
R9    -   1K 1/4W Resistor   
Q1    -    BT136 TRIAC    (need heatsink)
Q2    -    BRX49 SCR   
T1    -    12V, 4A Transformer   
F1    -    3A Fuse   
S1    -    ON-OFF Switch, > 5A  at 110 or 220V

Misc- If circuit work on box then a fan is might be necessary.


automatic 12v battery charger

It's fully automatic and will charge at a rate up to 4 A until battery voltage reaches a preset point at wich it still switch a very low current float charge. If battery voltage drops again, charger willl begin charging until the voltage reaches the cut off point. We can be left connected a battery forever maintain full charge without causing damage.

If circuit is powered off, disconnect battery otherwise battery drain slowly to it.

Adjusts:

R2 adjust proper charge voltage. Flood and Gel batteries charging at 13,8V otherwise AGM or GEL use 14,5 or 14,9. To adjust, turn on charger and a battery, R2 in midway, turn on charger. Monitor charge with a voltmeter until battery reaches proper end voltage then, adjust pot until led grow. Charger has set.