We are are required to wear our helmets at all times. I use a nitrogen-mesh cooling matrix that is integrated to my climate control body mesh for use in adverse weather/temperature situations. My asbestos lining causes my suit to be quite warm, especially when I am using my flamethrower. And I am prone to being warm due to my weight problem.
You guys have fans in your helmets !!!... does it really get that hot after a while
If what you're saying is true, that the batery is getting hot in the "OFF" position, then the problem is that you wired the switch incorreectly (and believe me, this is a common mistake among those who are wiring in fans).
Check to see how you wired it. You only want the switch in series with ONE of the power wires. If both your positive and negative wires go through your switch, then the problem is that you are shorting the battery when you turn the fan OFF.
If this sounds like what's happening and you need more clarification, let me know.