1025 Fan switch kills battery

So I'm getting ready to get a auxiliary battery to install next to my stock gel battery because my fan kills my current battery even though i have a manual fan switch and turn my fan off right after I turn my bike off. Ah Modification repercussions

how did you wire in this relay. unless you wired it in to run with the key off it shouldn't draw any power in the off/key off position. And even then with the switch off it shouldn't draw power.

I have a manual switch wired inline with the 27010-1026 Voyager fan switch and I turn the fan off when I turn off the engine.

So you are just bypassing the sender unit with the manual switch.
If that's the case I can't see it draining the battery have you done a parasitic draw test on the system?

Wasn't the original reason for the fan to run, was to cool the engine water jacket down even after you turn it off?, wouldn't turning it off manually cause some sort of uneven hot spots ?, although going with that idea the water pump doesn't run at all so it's really doing nothing but cooling the radiator water and maybe some sort of convection current is circulating the rest of the fluid ?, dang I really don't know what i'm talking about ... sorry

The manual switch is used with the 1026 Voyager fan switch so the family will turn on at a lower temperature AND the manual switch is to turn off the fan when the bike is turned off so the running fan doesn't run the battery down. I think I need to flush my cooling system and wrap my headers.