You will need
  • The transformer TS-180-2, wire size 2.5 mm2, four diode Д242А, network plug, a soldering iron, solder, fuses 0.5 A and 10A.
Take the TS-180-2 (power transformer from black-and-white TV). It has two secondary windings, which are designed for a voltage of 6.4 V and a current of 4.7 A, connect them in series, thus obtained output voltage is equal to 12.8 V. It is enough to charge the battery. On the transformer, connect the wire cross-section 2.5 mm2 pins 9 and 9` and the terminals 10 and 10`, wire cross-section 2.5 mm2 solder a diode bridge which consists of four diodes Д242А, fit and others that are designed for a current of 10 A.
Install diodes on the big heat sinks. The diode bridge assemble on glass fibre laminate wafer of the desired size. Connect the primary winding of the transformer in series, place a jumper between terminals 1 and 1` , to the terminals 2 and 2` and solder the cord with plug for 220 V. In the primary and secondary circuits replace fuses, respectively – 0.5 A and 10 A.
Unplug the charger. Reconnect the battery. The voltage at the battery terminals during charging should not be more than 14.5 V. To control the current and voltage, connect a charger ammeter with a scale dimension of not less than 10 A, and a voltmeter with a scale dimension of not less than 15 V. Also, it is possible to control with a multimeter, which limit the measuring current should be at least 10 A. Limit the charging current by including in series in the gap "minus" wire 12 Into the light output of 21-60 W.