That little disconnect works great. I used to use it in my commercial boating days. They work well for modern vehicles that also have phantom drains if to be stored for a while.. Also, add to theft protection as they can't be jump started... That's a great bonus.
They don't work with batteries such as side mounted connectors such as on my Chevy truck.. but, house batts in the RV are a great combo.
Also.. another phantom drain that draws a lot from the battery is the amplifier on the TV antenna.. don't ask me how long it took to realize that.