uC monitor voltage using ADC and turn on/off charger code example :
Alarm System 12V Lead Acid Battery Charger (Simple Example Version)
http://www.libstock.com/projects/vi...d-acid-battery-charger-simple-example-version
Charging process require voltage and current control.
18V transformer is ok.
Charging voltages according to ambient Temperature for your battery should be :
0°C 15.2 to 15.6V
25°C 14.5 to 14.9V
40°C 14.0 to 14.4V
At 25C Float charge voltage range 13,6-13,8V, 1,08A max current of charging.
At 25C Cycle charge voltage range 14,5-14,9V, 2,88A max current of charging.
Maximum charging time should be less than 24 hours.
Additional info maybe useful for you :
At 25°C temp capacity according discharge time :
20h 7.2Ah
10h 6,8Ah
5h 6,3Ah
1h 4,9Ah
Internal resistance at 25°C 21mΩ
Best regards,
Peter
;-)