1. Charging circuit
Charge current: I=0,45V/R2
Power-dissipation by R2: (0,45 * 0,45 / R2) !
Please adjust 13,8V by R5 without connected battery.
D1 - D4, D6 :
|charge-current less than 1A:||1N4001 (up to 1N4007)|
|charge-current up to 2A:||1N5401|
D5: 1N4184 , 1N4001.
Transformer: 15 V max 2 A
The L200 must be cooled.
2. Simple charging circuit
based to the PB137.