Poorman’s Glycol system

A real glycol chiller is expensive, and DIY glycol chiller from an air conditioner is kind of too hardcore for people like me. Therefore, I am using a re-purposed fridge as “glycol” chiller. The air is bad heat conductor, so I ended up using a bucket of water and bending the plate into water. It works really well except that the water sometimes gets frozen because I  use no glycol but plain water. One thing I also observe is that the beer temperature seem to be more stable if the temperature of “glycol” is not too cold.

In a nutshell, a temperature controller is necessary to control the poorman’s glycol chiller.

I have a spare BPL, but somehow I don’t want to use it. The BPL I am using has a two way relay board, and I am using only one for cooling, controlling the pump. The temperature of “glycol” is monitored by the “room” sensor. Simple hysteresis temperature control with timed constraints to protect the compressor would do the job.

I am not going to make it “official”, but I would love to share if anyone wants to try it.

The option is not enabled by default, so you have to build it by yourself.

build_flags = -Wl,-Tesp8266.flash.4m.ld -DEanbleParasiteTempControl=true

You will need a HTML file for setting. It is “paractrl.htm” in “extra” folder at Github. Manually upload it to BPL, and open it. The setting should be straightforward.

  • Enable Parasite Temperature Control
  • Cooling PIN /Inverted.
    Only coolingPin, heatingPin, and doorPin can be used. They are D5, D7 and D4 in default configuration. If they are used by BrewPi temperature control, the options of PINs used will be disabled. You CAN mess it by selecting the PIN and later assigning it for cooling or heating in Device Setup page. Don’t do that.
  • Target Temperature
    The cooling will stop when the temperature is equal or lower than this value.
  • Triggering Temperature
    The cooling will be kicked when the temperature is greater than this value. This value should be at least 0.5 higher than “Target Temperature”
  • Minimum Cooling Time
    Must be greater than or equal to180 (seconds).
  • Minimum Idle Time
    Must be greater than or equal to180 (seconds).

Sharing BPL log online

Here is a new easy way to share BrewPiLess logs over the internet, on-line.

Step 0: Hosting on GitHub.

If you have your own host, it should be easy and you can skip this part. Using GitHub hosting service is simple and easy. I would suggest you too google on this subject to find better illustration and description.

Step 2: Get the log viewer

Get the “BPLog.htm” file from my GitHub:


Don’t forget to get the “raw” version.

Step 3: Upload the file and logs to share

The logs will be put at the same place as the BPLog.htm file. Subdirectories can be used. I put my log in a subdirectory, named “log”.

Step 4: Test the shared link.

First open the log viewer page on your browser.  The url should be something like


If you can see the empty log chart page. You are almost done.

Step 5: Create the shared link.

Append log name after the URL above in this format

https://your_name.github.io/BPLog.htm?log=[Your log name]

If the log is put in a subdirectory, replace “/” by “%2F”. You will need to uriEncodeComponent special characters. If you don’t understand previous sentence, please don’t use special characters in the path and log file names.

eg. A log name “nottingham.035.20171114” in subfolder “log


Copy the URL above to your browser or see it in a iFrame here:

Step 6: Optional with selection range

Select the desired range, right click mouse on the chart.

A menu of “Open Selection” will popup, click that item to open a new window that will zoom to the selection range on open.