VoronUsers/printer_mods/Ellis/Bed_Fans/README.md

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## <b>Macros and Usage</b>
See <b>bedfans.cfg</b> or <b>bedfans-dualcontrol.cfg</b>* for klipper macros.
<b>1)</b> Place the .cfg file in the same directory as your printer.cfg file.
<b>2)</b> Add `[include bedfans.cfg]` to your printer.cfg.
<b>3)</b> Change `pin` for your fans in the second section. This is intentionally left blank so that it will error if you don't fill it in.
<b>4)</b> Configure the options in the first section:
* `variable_threshold` sets the target bed temperature at which your bed fans will activate.
* `variable_slow` sets the "slow" fan speed for when the bed is heating to the target temp.
* `variable_fast` sets the "fast" fan speed for when the bed is at temperature.
* This may have to be lower than 100% fan speed, especially with quad fans.
* If you get <i>"Heater heater_bed not heating at expected rate"</i> errors, then you have set this too high.
The macros will intercept bed heating commands, so you do <i>not</i> need to add anything to your other macros.
\* <i>Optionally allows for setting inner and outer fan speeds separately, for a quad fan configuration. I like to set my inner fans to be run slightly slower to try and keep the airflow somewhat even.</i>
## <b>5015 Fan Mount</b>
Bill of materials (per fan):
- 1x 5015 fan
- 1x M3x25
- 1x M3x20
- 1x M3 heat set insert
- 1x M3x8 or M3x10 <i>(optional, I only mount with one screw)</i>
![5015 Fan Mount](Images/5015_mount_isolated.png)
## <b>FAQ</b>
#### How much difference does it make?
* My chamber now reaches about 60-66C with a quad fan configuration, whereas it only reached roughly 48-50C previously. Chamber temp is also reached more quickly.
#### Can I push it further?
* Technically your bed heater is not being run at full power with the default configs, however I <i>do not recommend pushing it.</i> Since you can't control max power at runtime, your bed will run at too high of a power while heating, risking warping your bed.
* <i>I also do not recommend tinkering with your verify_heater (thermal runaway protection) settings.</i>
#### What power should I run my bed heater at?
* Recommended max_power is 0.4 watts per cm<sup>2</sup>:
```
For example, for a 300 mm^2 bed:
30 cm * 30 cm = 900 cm^2.
900 cm^2 * 0.4 Watts = 360 Watts max.
If you have a 750 watt heater, that's 48% power, or 0.48 max_power.
```
#### Do I need to PID tune my bed again?
* I did not find it necessary. Bed heaters do not seem to be terribly sensitive to this.
#### My bed temperature dips when the fans kick on fully, is this normal?
* Yes, this is normal. It should recover within 60 seconds. If not, then your fan speeds are too high.
#### What brand fans should I use?
* I just used generic multi-pack fans. There is no need for anything fancy here.
#### Should I use single, dual or triple/quad fans?
* Triple/quad fans is more for <i>even</i> airflow than <i>raw</i> airflow. In fact you will likely not be able to run them at 100% without outrunning your bed heater. I personally prefer triple/quad fans to avoid any possibility of "tacoing" my bed due to uneven temperatures. Triple fans is probably the "sweet spot".
#### Is "dual control" necessary?
* Almost certainly not. I originally set it up that way because it was easier to wire in my particular case, so I took advantage of it. Triple fans with "single" control is probably the best balance of cost, complexity, and performance.
#### I insist on running quad fans at 100%, why am I having a bad time?
* No. Stop it. Bad.
## <b>Images</b>
<i>(looks a bit tight since CAD is for a 250mm)</i>
![5015 Triple](Images/5015_triple.png)
![5015 Quad Installed](Images/5015_quad_installed.png)