Battery fire

[dbutler_05]

My father-in-law recently bought a 1999 Four Winns 220 Horizon(5.7GXi engine). It was last run when it was winterized at the end of last season. This weekend we tried to start it up before putting it in the water. dead battery. We replaced the battery with a walmart marine battery. I installed the battery and turned the dual battery switch from off to one. At that point, the negative terminal caught on fire. I immediately turned it off. Once the fire was out, I tried turning the switch to two. That caused both the battery and switch to smoke. I stopped there. Any suggestions on what could be the cause of this? To our knowledge, the boat hasn't had any major work done on it.