My original battery has been in use for 4.5 years, so I figured that it was time to replace it. When I replaced the M-B battery, I noticed that there is a (drainage?) hose that connects to the top of the battery. What is this for? There appears to be a hole on the new (Interstate) battery, but it's ovular, not circular, like the M-B battery's. Do I need to connect a hose to this? I thought that this is a sealed battery, and therefore would not need anything to drain from it. Can someone shed some light on this?