Sunlu S2 Bottom Panel Alternative

Overview

This is a 3 Parts upgrade to your S2. All 3 can be done independently. All 3 will improve the performance of the S2 in their own area. I declare it as WIP as further testing showed varying results.

Feet Replacement printable (STL/3mf)

This will replace the original bottom Panel (with Feets) for a new 3d printed bottom Panel. This new Footer will generally work same as the stock one but with benefits. The Fan is screwed in same as stock location and direction(as indicated by the Arrow on the print). Why print that you may ask:

1*) This replaces printable Lit Spacers. With the Fan in original orientation there is a passive vent next to the fan that will vent to the outside. After many iterations this is as good as it may get. Comparing to the fully closed, moisture levels drop slower but over time to compareable level similar to the Lit spacers, which can be found in various shapes, but its doing that at the lowest point where air is the coldest. which is very effective in keeping heat in while dropping moisture content.

2) you could tape off the inner opening to have a sealed bottom piece to replicate stock scenario. There is still a benefit still using this print, cause this Footer decreases the chance for the S2 to tip over significantly.

3) There is a hole under The Fan. So you could install the fan upside down. The opening next to the fan is slightly restrictive for fans air-volume which will cause some of the air getting pulled in from the outside. I did many tests and it was still possible to get 70c(measured externally) but due to the draft generated the internal probe would start to read low which will cause massive issues with petg and PLA as they would be dryed effectivly hotter then they should. Going this direction its mandatory to externally monitor the temps for the filament inside.

4) (WIP) minimalist Litspacer. Its just opening the Lit enough to reveal a tiny airgap up top. Im still testing if this will work for PLA as well as for ABS. 
For Installation pressfit(its a bit tight on purpose) Part A into the Base(see image). Optional: Apply glue to part B and place it on top of Part A. The small lip on Part B will help you seat/rest it against PartA while this is still on the seated in the groove of the Opening.

Caution: You will likely need to unscrew the bottom Heater Panel to tape down the fan wires after modification otherwise they can touch the hot surfaces which could partitially melt them.

Print recommendations:
PETg, 3 Walls, 4 Toplayer, 3 Bottom Layer, 8-10% Honeycomb infill(this creates closed cells which reduces noise)

Insulation Upgrade (PDF)

To reduce the Power consumption overall, but also to reduce "heating to operating temp" time its a great benefit to add insulation to the inside of the S2. Ill provide a PDF in the Files section which have cutting templates. 
From my testing this reduced heating up time by ~30%

You need:
2x* “3D Printer heating bed Insulation”(i.e. AliExpress or similar), 310x310mm, max 5-7mm thick, Sticker/adhesive on one side, Aluminum on the other side. 
*Technically you need one sheet but thats very tight so in case you need a little extra better order 2 pieces.

How to:
Print the PDF with 100% scale(no crop to fit or anything, fits US letter and DinA4) and cut out the templates. Trace the cutout pieces onto the Aluminium side of the Bed Insulation material. Cut out the Pieces and apply to the inside of your machine. The PDF contains an extra image showing where the different Pieces have to go.
 

Temp Probe Relocation (PDF)

I wont go into details here. The Probe is glued to a standoff. its very likely that you break the wires trying to get it off it. Instead you could break away the standoff itself and relocate the probe to inside the heated area. This will improve the temp reading accuracy alot. I tested alot with the right location. Look through the images - ive attached one image showing the new location taped on with capton tape(or any real thin tape). This position reads very accurate now.

How to:
not recommending anything here as you will likely need to permanently damage you device. If not careful you might rip the thermistor wires which puts you at a full loss then!!!.
The Image showing the Probe relocation is in the PDF for the Cutting Templates.

PTFE Guide

For completness sake the minimalist PTFE guide: https://www.printables.com/model/928086-sunlu-s2-bowden-passthrough

Version History

v06e - refined lit spacer
v06d - improved internal structure for printing slightly
v06 - initial Release

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*Disclaimer for Feet Replacement(1):  drying PLA(low temps) shows that the Bottom Panel alone with the little heat inside doesnt create a strong steam pressure to force the moisture out the bottom vent so it may still be required to use a lit spacer for PLA. For PETG and ASA i could successfully dry it just using the bottom vent. For ASA/ABS its important not to use Lit spacers as you otherwise never reach 70C inside the spool. The Minimalist Spacer is still in testing - i hope it will get the balance just right so that 70c are still reachable