Thanks to jdobry and Buszmen61 over at Thingiverse for the inspiration for the great Sunlu S1 mods. sunlu FilaDryer S1 Fan by jdobry - Thingiverse. Sunlu & eSUN filament drybox - holders for hygrometer without drilling by Buszmen61 - Thingiverse
WHAT I MADE
I started with the fan from jdobry and created a ramp to direct air flow around the filament spool. It uses the stock screws from the rear plate. I originally had the S1 facing the back and wanted the hygrometer to be visible, but didn't want to interrupt airflow, so I then made the Ramp with Mount for the Hygrometer mount made by Buszmen61. It worked okay, but was a bit too high. Plus, I printed it in PLA, so it started warping pretty quick. So, I modified it to sit lower and a bit away from the ramp, to allow air to circulate freely, and recommend PETG.
I included the STL for the fan for easy access. For wiring instructions, I encourage you to hit jdobry's link above and give him a like. Of the designs I saw, this was my favorite. I didn't screw the fan to the lid. I used a single strip of double sided tape and it has been working great for a couple weeks now… almost non-stop. Use a 4010 axial fan, soldered to the power wires. I put a 40C Thermal switch in-line. When chamber temp hits 40, it turns on and circulates the air. When heater turns off, fan keeps circulating air until temp drops below 40. From what I read, this improves efficiency by like 3 times.
If you have questions, send me a message. I can provide more info. I am no longer using the rear hygrometer, which is why I made the smooth ramp. I am using the front PETG anchor with hygro I also have posted.
The author remixed this model.
Customized the holder to fit in the ramp or mount to the front of the S1.