Any parasitic drain should be down in the milliamps; even one amp is way too much. Start disconnecting circuits one at a time until you find which one is causing the current draw. Do you have a modern radio with a keep-alive circuit for the electronics, or some other system that's powered up all the time? Also, are you running a 6 or 12 volt system? Sometimes a 12 volt battery with a very dirty top will self-discharge due to current leaking from one terminal to the other, but I've never heard of a 6 volt system doing that. If a battery is left idle without being used for several weeks, it will slowly self-discharge.
Jerry
