Method of electrolyte bath stabilization

A method of stabilization of electrolyte bath in electrocoating for obtaining electrodeposition coat by immersing a substrate in the electrolyte bath filled with a cationic electrocoating composition containing a basic resin and an amine compound and carrying out electrocoating;

• wherein said basic resin in said electrolyte bath contains, per 100 grams of the resin solids, 10 to 300 millimoles of sulfonium group and 50 to 2,000 millimoles of carbon—carbon unsaturated bond, and;
• said amine compound is contained in an amount of 1 to 50 millimoles per 100 grams of the basic resin solids in the electrolyte bath, said amount being not less than 5 mole percent relative to the sulfonium group content in said basic resin, so that the sulfonium group remaining in said electrodeposition coat amount to not more than 50% relative to the sulfonium group contained in the electrocoating composition in said electrolyte bath.