@
emme3 I'll share with you what I have done so far. After playing around with the fan placement, I opted to go with the more common set up that others have done in previous threads.
Basically, place the fan behind the curve of the helmet cheek and point towards the visor to keep it from fogging up. You get good circulation. I had to play with the placement and angle a bit because certain spots caused the fan to hit my chipmunk cheeks. In addition, if you put it too close to your ear, the motor will drown out noise. Because my helmet is on the smaller size, I had to place the battery pack off to the side and not dead center to the rear. So far walking around my house, I think I have the placement that works for me. I opted to use industrial strength velcro to hold it in. Regular velcro wasnt doing the job. Make sure when attaching the battery pack to place the on/off switch towards the bottom. It really makes it easier to turn the fan off and on by reaching for it.
One more thing I did was add a bit more velco in the center of the battery pack. This little bump helps in securing the flat battery pack to the curve of the helmet. I plan on possibly adding a mic and noise amplifier, but we will see how much room I have, but hopefully this helps to get you started.