Battery tender & storage

I had battery disconnects on my two vehicles. When I left in the motorhome for more than a month, I throw the blade on the disconnect. When I return, I reconnect the blade switch. It has always worked on my two vehicles and they start right up. I recently replaced the one vehicle with a new Honda Odyssey. When I lifted the hood, I couldn't even see the battery, there is so much stuff screwed on top. So I asked my mechanic. He said not to use a disconnect because there is a small watch type battery that powers the ecm and if that were to go dead from the battery being disconnected, I would have nothing but problems with the battery vs the computer. He recommended a Schumacher 1.5A battery maintainer. I bought it and he installed it yesterday. It is forever mounted under my hood and the plug sticks up within easy reach of an extension cord. This device is specifically for vehicles left in storage and I am hoping it works as advertised.

Dale