Overcharge preventive device for automotive batteries

An overcharge preventive device for a battery charging circuit of an automobile which includes a battery and a charging generator circuit coupled across the battery, said overcharge preventive device comprising:

• odorant sensor means for detecting an amount of gas developed from said battery when the battery is being charged by said charging generator circuit;
• overcharge detector means, connected to an output of said odorant sensor means and disposed near said battery, for identifying when said generator circuit malfunctions and causes an excessively high charging rate to be supplied to the battery based on a level of said output of said odorant sensor means, said overcharge detector means detecting an overcharged state of the battery when the output of said odorant sensor means indicates that an amount of gas detected by said odorant sensor means has exceeded a predetermined level, the overcharge detector means outputting an output signal only when a generator circuit malfunction is identified;
• interrupter means, connected to the overcharge detector means and connected between the battery and said charging generator circuit, for automatically electrically separating said charging generator circuit from said battery in response to said output of said overcharge detector means which is generated only when said generator circuit malfunction is identified;
• and
• alerting means, connected to said overcharge detector means, for alerting a driver of said automobile that said generator circuit malfunction has occurred in response to the output of said overcharge detector means.