At work I am curntly building a battery charger.
I took a 220v to 10v transformer and took out the secondary windings because I wanted to make it a 12v, I rewinded it with 2.5mm flexible cable untill I got my 12v. The transformer works well untill I connect it to the battery, the current rises to anything between 10A and 17A and the voltage rises to 16v, witch according to me is much to high for charging a battery. When I connect a normal load like a motor or light it works 100%. I have even took out some of the windings to drop the voltage to 11v but still gets the same problem.
What may be the cause of the problem?
Any help would be appreciated