The microwave oven has a very powerful transformer, which can be used in a homemade charger for 12 V car batteries. Let's rewind the transformer to suit our needs and assemble the charger.
The first step is to disassemble the microwave oven and remove the transformer from it.
You also need to take a fan and a power cord from the microwave. At the transformer, use a hacksaw to cut off the high-voltage winding (2500 V) and the middle low-voltage winding (6 V). All these windings serve to start the magnetron. We leave the mains winding (220 V), usually the lowest one.
We clamp the transformer in a vice and use a chisel to knock out the remains of the sawn windings.
Now you need to wind a new, low-voltage winding on the transformer with a 2.5 kW wire. mm.
We wind 15 turns. We connect the transformer to the network and check.
Output is 13.3 VAC. This is not enough. We wind another 2-5 turns to a voltage of 15 V.
Now you can start making the charger.
Charger diagram:
On a rectangular piece of chipboard we attach a transformer, a fan, a diode bridge with a fan, and a switch with a power supply box.
We connect everything with wires according to the diagram.
Instead of a fuse, for clarity, we’ll plug multimeter for current control.
The charger works, the battery is charged with a current of 4.5 A, which is quite normal. The transformer heats up, but much less than when working in a microwave. The fan does a good job of blowing.
As a charger option, letting the battery charge for 1-2 hours to “revive” it will do just fine.
