So, I wanted to share a really cool,upgrade I did and tested this last weekend. I must say for our type of camping, this is a must have mod.
I basically combined two mods into one for the stock fantastic vent. I added a variable speed controller and a reversing switch, so the fan is infinitely controllable from slow to super fast, and you can reverse the motor to not only suck air out, but suck air in as well.
Credit goes to ksherzi who posted his variable speed post below. He identified a PWM board that is quiet, some are very noisy (high pitched).
Original post from kscherzi;
In his post, he credits another user for the idea and it has some more pictures, link is below:
The reversing switch idea came from RFP on the 23D thread. He found a drop in three way reversing switch that replaces the stock on/off switch perfectly. Rob started the conversation on this switch at link below, Post #1490.
This Mod will cost about $35 per fan. The two parts are the variable speed drive board (PWM), and the switch. Here are then.inks to the specific parts. Make sure you get the exact board the kscherzi sourced. I tried to get fancy and got a different one first and it had a high pitch whine as he mentioned in his original post the frequency is key to quiet operation.
Install is fairly easy. Unscrew 5 screws, take fan enclosure down, remove wire connections, drop old switch and old control knob out, make a few new wires, put it all together, and then you have a reversible variable speed fan. This thing ROCKS! At night we could keep the fan on low to get air and moisture out while sleeping (5 in a 23D), and it was ultra quiet. Before the stock version on speed 1 was so loud.
Pictures below to help with install, if you have questions, send me a PM, glad to help. Also, first three pictures are wiring diagrams, one I made for the mod, and one each wiring from switch and board manufacture.
The photos are of my install and wires etc. I attached the PWM board with two sided tape in the 4 corners, shown below.
After fan enclosure is dropped, shows wires
Back of PWM board with two sided tape
New board installed
New switch install