I use car about once per month, autocross mainly. I turn on, and let her idle for 10min, just to keep fresh, maybe once per week (small battery). So, it didnt turn on yesterday, so i though batt. was dead. I charged it today and nothing. The ecu clicks on ignition, then clicks again a few secs later, like normal when ignition off. Car is pretty much stock, besides suspension. any ideas?