DIY: Very simple heater for fermentation temperature control

Hi all,
winter came and I felt the urgency to heat my fermentation cell which is, btw, a fridge. I have an electronic controller that acts as a thermostat that turns on the fridge when I the fermenter temperature goes over a certain level. Now that is cold, I wanted to turn something else on when the temp goes down. I thought about terrarium heating pads, but I had two problems:
- decide how many watts are enough for my situation (my basement is about 15°C by now and I want to be able to arrive at 22-23°C in my fermentation chamber);
- buy the heating pad online (the vendor had a problem, things were going longer than expected).

I had a brew coming along and I had to find a solution. What came up is:
- a relay that is triggered by normal AC. I attached the relay trigger to the thermostat exit and the normal AC to the power pin. So the two exits are one identical to the thermostat exit and the other is the opposite (I use this one and I will call it "inverted trigger").
- the "inverted trigger" goes to a 25-50W solder. I was worried to set everything on fire, so I tried to attach an old cpu heatsink to the solder. After some thinking, I decided to make a hole through it: it's more stable and the heat goes away with no problem.
- the "inverted trigger" goes to an electrical transformer used to power up an old phone too. I use this to power up the computer fan attached to the heatsink. I took a look to the transformer to see how to choose the exits for the heatsink. I was lucky, the cpu fan input is 12V but the 9V transformer was enough to make a proper work.

When the solder is turned on, the fan is turned on too so there is no problem. I saw that the heatsink temp goes up to 30°C. The fan helps the temp to spread in the cell too and I found out that 25W are enough for me.

I had everything in my house, no part has been bought and I then was ready for the brewday!

Hope it helps!
Cheers from Italy!

Piteko

Very resourceful! I applaud you on your ingenuity.

But I would not say that is simple. Simple is buying a $12 heater/fan/thermostat device like this. I have no idea what is available to you in Italy, but surely you can find something similar.

I have one of the ebay dual temp controls with the fridge plugged into the cold outlet and a little lamp plugged into the other. A 25 watt light bulb has been sufficient to keep my temps where they should be so far this winter.

See all those splices with masking tape (or maybe medical tape?) over them really gives me the willys. At the very least, use electrical tape if you're not going to solder the connections together.

weirdboy said:

See all those splices with masking tape (or maybe medical tape?) over them really gives me the willys. At the very least, use electrical tape if you're not going to solder the connections together.

Click to expand...

I was thinking the same thing. Paper tape around electrical splices is a recipe for disaster.

passedpawn said:

Very resourceful! I applaud you on your ingenuity.

But I would not say that is simple. Simple is buying a $12 heater/fan/thermostat device like this. I have no idea what is available to you in Italy, but surely you can find something similar.

Click to expand...

I have one that it's just like the same here. Only thing is the thermostat feels temperature from the fermenter. In the meantime, the whole fermentation cell is under the heat pressure of 1200W. So, if it takes 2-3 minutes for the thermostat to feel that the temp has gone up and has to switch the circuit down, you have 1200W turned on for 2-3 minutes, which I suppose will give you a "temperature saw" very high.

And I don't know if that heater/fan will shout itself for the air temp in that low air volume...

Just my 2 cents, but that's why I opted for the solder, less power, more time for the thermostat to understand what's going on

Cheers!
Piteko

weirdboy said:

See all those splices with masking tape (or maybe medical tape?) over them really gives me the willys. At the very least, use electrical tape if you're not going to solder the connections together.

Click to expand...

Connections are soldered and the paper tape is just for me to handle it a bit freely. Only one phase is present (on both the pins) in the switching part of the relay, the other is closed on itself.

I personally hate electrical tape. The glue tends to be unrealiable over time. Not the paper tape is better, but since I avoided close circuits and this is a thing that lasted one week (the fermentation time) for a load of 25W of power, I thought it could be acceptable

Isn't it? I'm ready to understand why, perfectly understanding that seeing this from outside could feel me creepy too

ktblunden said:

I have one of the ebay dual temp controls with the fridge plugged into the cold outlet and a little lamp plugged into the other. A 25 watt light bulb has been sufficient to keep my temps where they should be so far this winter.

Click to expand...

I read conflicting opinions over light bulbs. For the light emitted, for the temp they make without the possibility to dissipate it and the fact that heat tends to cumulate on top of the cell. I thought about infrared bulb heaters too (generally available for terrariums too).

Anyway, the point of the post was not finding the perfect solution. The point was finding the fastest patch, understand how many watts I needed and then move one with a better solution (a heater pad for me)... If my patch can help you solving a problem, than it's worth sharing

I don't mean to keep this infrastructure

Cheers from Italy!
Piteko

piteko said:

Anyway, the point of the post was not finding the perfect solution. The point was finding the fastest patch, understand how many watts I needed and then move one with a better solution (a heater pad for me)... If my patch can help you solving a problem, than it's worth sharing

I don't mean to keep this infrastructure

Cheers from Italy!
Piteko

Click to expand...

haha. Yes, you did a great job of using what you had around you to heat your fermenter. Really, nice job.