There are lots of issues with car batteries. One of them is charging. You need to charge it if you haven’t use your car for a week.Headlights or dome lights left on.
The reason for losing battery power is normal there are the various reason: Headlights or dome lights left on.
Headlights or dome lights left on.
The battery is in weak or poor condition.
There are multiple solutions also you can use a Voltage regulator to regulate power flow to your battery.
Quick disconnect, short term fix, nice for long term storage and very easy disconnection when working on electrical. And ditto on the pulling fuses to find which circuit has the drain.