Since the charger from Milos Zajic has limited maximum charge current to 1A, larger capacity batteries are charging longer time than it is when charging by 1C. Therefore I decided to build more chargers and incorporate them into a common box. I made a charging station which is able to charge two or three accumulators of any capacity and combination at the same time. This partly offsets the long charging time due to the current limited charger. Because three chargers also may take up to 3A, I had to look for a stronger source of voltage supply. The original transformer from trains PIKO was not enough for such collection. I found a toroidal transformer 2x24V in my drawer ( from the times of my experiments with hi-fi amplifiers). I also already had rectifier diodes and filter capacitors. So I bought three stabilizers LS78S15, several heat sinks and components for chargers and voltage limiters ( balancers ). PCB, I copied in triplicate to the larger plate, added some connectors for charging. I built in everything a black plastic box. I'm using this charging station more than 2 years. During that time i had zero explosions, zero accumulators damaged and lots of successful charging cycles.
After a time, I decided to buy universal charger/discharger for larger currents. It requires external power supply. I purchased one for PCs and built it into a box along with the charging station. I connect out the +12 V and -12V for external charger.
PC power supply had to be modified. First I unsoldered all output wires, then I have to load the +5 V output about 0.6 A (connect two 6V light bulbs 0.3 A), without which some PC power supply does not work. Then I mounted the PCB in a box and used a fan to cool the entire device.
For orientation, mentions the price of individual components:
1x PC power supply - 18,- EUR
3x charger MZ - 12,- EUR
3x voltage limiter (balancer) MZ - 20,- EUR
1x toroidal transformer 2x24 V - 24,- EUR
3x stabilizer 78S15 - 1,44 EUR
Other material (heat sink, box, connectors) - 14,- EUR
Charger with balancer G.T. Power A6 from HK - 49,- EUR
Total cost: 138,80 EUR ( 89,84 EUR without GT Power charger )