High Performance Gelled lead acid charger

This high performance battery charger circuit allow quickly charges gelled lead-acid batteries, and automatically turns off at full charge. First, the charge current is held at 2 A, but as battery voltage rises, the current will decreases. When current falls to 150 mA, the charger automatically switches to a lower float voltage to keep from overcharging. When you hit full charge, transistor Q1 lights the LED to indicate that status.

Gelled lead acid charger parts list :
R1 : 3K
R2 : 15 ohm
R3 : 230 ohm
R4 : 15 K
R5 : 1K
R6 : 0.2 ohm
R7 : 500 ohm
C1 : 0.1uF
C2 : 1uF
C3 : 1000pF
Q1 : 2N2905
U1 : LM 350
U2 : LM301A
Led
S1 : push button