If the battery is dying in that short of a period of time and the bike is not running, you have a choice of two possible problems. Here is how I would approach it. First, make sure that the battery is fully charged. Then, disconnect the battery leads completely, from the bike. Let it sit for 8 hrs, 2 hrs, whatever amount of time that it would normally be dead. If the battery is still fully charged, you have a problem on the bike with something causing the battery to drain (something is grounded that shouldn't be). The second scenario is if the battery has discharged while NOT hooked up to the bike, and that means that you've got yourself a defective new battery. Something internal in the battery. Sometimes, they will be dropped while shipping or handling them by someone and the internal plates will actually short together. Nothing you can do about this situation except take the battery back and get a new one (hopefully it is warrantied). Hope this helps