Do you have a multimeter? If so, check the battery voltage after it’s been sitting. It’s likely the battery needs replacement. A battery with 300CCA would be the way to go. I recommend that you get a battery tender and keep it hooked up when not in use. Also, periodically check the electrolyte level in the battery and top up with distilled water, when necessary. Keep your terminals clean.
The seat safety switch isn’t draining the battery.