Review on ⚡️ dkplnt 120W 48V 36V to 12V 10A Converter Golf Cart Voltage Reducer Regulator Waterproof: Efficient Power Solution for Golf Carts by Andrew Pierceson

Came without detailed instructions, only wiring diagram. You might think this would be enough. What they don't tell you is that the device contains a large capacitor. When you first connect the device, it should charge a capacitance that produces a very large spark. To pre-charge the capacitor before connecting the last wire I used a 60w lightbulb, placed the soldered end of the lightbulb on the battery post and held the wire to be connected to the side of the lightbulb. The light acts as a resistor, allowing the capacitor to gradually charge up. Quickly attach the cable to the battery and you avoid the anxiety I had when I plugged mine in. You only had to put a small piece of paper in the box and that would have saved me a lot of nerves and time.