At the start of November, I completely remove the battery from the car, and attach it to the Deltran Battery Tender Plus. I leave it that way to the start of May. The car goes into storage for the winter, I take it out so it will not freeze and go flat.
I noticed that this year (and a little bit last year) there's a brown colored liquid leaking from it (I can tell it is brown since it is on a white table). It is a very tiny amount, but it will accumulate over time (after a month and a half the brown stain will be about 3 inches in diameter). I think it is coming from the top, I'm just wondering if this is the result of leaving the battery tender connected. It is still doing it a bit even when disconnected. The battery tender brings it to a floating amount of about 13.2 volts. When disconnected for a few days it stays around 12.8 volts.
Also just a side note, the battery was bought new in May of 2016. It is a Car Quest brand battery. The previous battery was a genuine Ford and lasted 12 years. I went with Car Quest battery not to save money, because the Ford one is hard to come by being an older car (they take a month to come in). My dealership currently has one Ford one in stock and I'm debating on buying it despite the fact I will not be using it until May.