Something drawing on my battery

I decided to go with the battery disconnect. I purchased a good quality one for each vehicle. I don't use them on a regular basis but one vehicle has to be stored because we only have one parking spot. I will use the disconnect on the vehicle that will be stored for a few months.

I intend to look at the isolator. It is quite likely that is the problem.

Thanks everyone for your input. I now have a temporary solution to the problem at a very reasonable price and can now look for other solutions as we get time and opportunity to do so.