Welcome to Minbari’s Workshop. This is going to be a log of any woodworking, beer or Car Audio projects that I will be working on. Hope you enjoy it.
July 4, 2015
I did this conversion so that my Coleman cooler would last longer and stop freezing my milk solid. once I posted it on our drivers facebook club I got alot of requests to do a simple how-to. If you have a basic knowledge of electronics or are not afraid to jump in and learn, there is nothing very complicated about doing this. Just take your time and follow the steps, if you have questions you can PM me at facebook and I will do my best to help.
Tools you will need:
- #2 Philips screw driver
- Small jewelers screw driver
- Torx screw driver
- Wire stripper/crimper
I bought all the devices for the conversion on ebay. you can get them other places, but ebay is easy to use and shipping is pretty quick. Make sure you select “only from US” in the filter or most of this stuff will come from china and take 4-6 weeks to get to you.
Any simple 12 volt temp controller will work This is the one I got, it was about $15.
Peltier Effect chip: Also known as a ‘cooler’ or ‘Thermo-electric’ chip. if you search for peltier cooler you will get results on ebay. Get 60-72 watt units, any bigger and you wont be able to cool the hot side enough and it will draw too much current for the plug end.
Heatsink compound: Do NOT forget this part or the Peltier chip will overheat and die very quickly. transfer of heat (and cold) from the chip to the heatsinks is important. Less is more with this stuff too. just a light coating on the whole surface of both sides of the chip is all that is needed.
Spade connectors: can get these at radioshack or lowes.
The following schematic and steps will help you rewire the cooler. Should take a couple hours to do.
Click PIC to enlarge
- Remove 4 screws from front of plastic cover and remove
- Unplug power wire and remove
- Slide up cover from inside cooler (covers heatsink)
- Remove 4 screws from fan on the inside and remove
- Remove 2 torx screws from heatsink.
- Carefully pry exterior heatsink off. It will be stuck on pretty well, use some force, but do it carefully.
- Remove old Peltier effect chip.(discard) just pry it out, but try to not deform the foam it is in.
- Clip wires from both fans and the peltier chip. Leave the wires as long as possible.
- Clean old heatsink compound off both sides of the heatsinks.
- Mount the controller. An exacto or utility knife will work to cut out the vents under the fan area.
- Crimp a spade connector to a piece of 16ga red and 16ga black wire for main power.
- Connect spade connectors to power cord (previously removed)
- Strip the end of the interior fan wires.
- Strip the end of the power wire and twist the interior fan wires to it. Connect to the “IN” side of the controller. be sure to connect pos and neg correctly or bad things will happen.
- Drill a hole for the temp sensor to pass through. I drilled mine from the inside just above the interior heatsink.
- Pass the temp sensor through hole and connect to temp controller.
- Put heatsink compound on one side of peltier effect chip and place on the metal block on the Coleman cooler. squish it around and make sure compound gets distributed nicely. Chip should pretty much stay put once put in place. Make sure wires are pointing down, NOT out the side like it was done with Coleman.
- Put heatsink compound on the other side of the peltier chip and re-install the exterior heatsink. screw heatink back into place with torx screws. DO NOT over tighten!!! heatsink is aluminum and will strip out fairly easy.
- Reinstall interior fan
- Strip wires for exterior fan and the peltier effect chip.(twist together) Connect to the “OUT” connector on the temp controller. Make sure the fan polarity is correct or it will damage the fan.
At this point you are basically done. double check your work and make sure that you did not make any mistakes with polarity. If you have a multi-meter (DMM) then ohm out the connections to verify it. otherwise just do it visually. Before re-installing exterior fan assembly go out to your car and test it out. (just set the fan over the heatsink)
On power up you should see the temp controller come on and display interior temp. press the “set” button once and then push the down button to set temp. (set to 30 degrees to ensure it comes on) exterior fan should come on and temp should very slowly start going down. After 5-10 minutes the interior heatsink should be cool to the touch. (if it is getting hot, go to the next step)
Once you are satisfied with operation, then tidy up the wires with some small zip ties and route the wires so they wont get pinched when you re-install the exterior fan assembly.
It should be noted there is no guarantee that this will not fail at some point again, the peltier effect chips have a limited life span. but with careful installation and cycling on and off, it should extend their life considerably. replacing the chip next time will be a 10 minute job since you have 4 extras and the heatsink compound already. 🙂
If Interior heatsink gets hot step!:
ONLY do this step if the interior heatsink gets hot instead of cold. With peltier effect chips there is no way to know which side gets hot and which side gets cold until you power them. powering them up with no heatsink can cause damage very fast, so dont do it!
- Remove wires from “OUT” connector on temp controller. (make a note of which wire went where)
- Untwist the wires from exterior fan and peltier chip.
- swap the side of the wires and re-twist them (so if red was on red and black on black, now they will be red on black and black on red.)
- Re-connect wires to the “OUT” connector of the temp controller opposite polarity from what you had previously. Fan polarity MUST still be correct. this was the reason for swapping them.
Test again and it will cause interior heatsink to get cold instead of hot.
If you have any question, PM me on facebook or email me
November 13, 2014
Finally got it all assembled. The march pump I got on ebay work better than I thought it would. With the ball valve fully open it moves alot of water.
With the controller set on ‘mash’ mode, it maintains the water at about 1/2 degree F. Since it is using a HERMs coil it does take a while to get to temp, 12 gallons of water between the BK and HLT with only 3kW.
In ‘boil’ mode with can get 5 gallons in the BK boiling in about 45 minutes.
November 13, 2014
So, I finished up the exhaust system for the brewery. As mentioned before it uses 3 high speed PC fans. They do a perfect job of keeping the humidity at a minimum
October 12, 2014
Before I found out that I lost my job about a week ago, I ordered stuff to nearly finish up the plumbing of my brewery. Nice shiney stainless stuff for the HERMs system as well as a bottle capper, caps, cleaning gear and all the other odds and ends I needed to make my first batch. First batch will get delayed a little, but will get made soon, I hope!
This is a used March pump. Got it for $45. not too bad!
October 12, 2014
Since I am setting up my brewery in the basement, humidity and heat from the boil is real issue. There are many way to exhaust the humid hot air out of the area, but none can be as in-expensive as this!
(3) 90 cfm server fans in an array, which will have a 4″ hose connected to a homemade hood over the boil kettle. only $9!
The square hole will get a flange on it to support the 4″ hose.
October 3, 2014
So this is more of a re-purpose than anything else. About 15 years ago we bought a dehumidifier from a thrift shop for about $50. Dehumidifiers work on the same basic pricipals as air conditioners, on a smaller scale. Major difference is that they are not meant to cool the air, but only remove moisture from it. (something air conditioners do as well)
I plan to use the evaporator to cool a water bath for temperature control of my fermentors. Idea is pretty simple:
- Disassemble the dehumidifier
- Bypass a couple safeties (ones that ensure the condensate bucket is in place)
- Relocate the evaporator (so it can go into the water bath)
- Add a temperature probe
- Add a control relay to interface the controller.
I got a start on the dis-assembly and relocation steps last night. Took a while to determine the best direction to take on this. Kinking or breaking of the coolant tubing and this unit would be a 50lb door stop.
Tested it and the evaporator gets really cold! I wish I had gotten a picture of the unit before I took it apart, but it looks like just about any dehumidifier out there.
Looked similar to this on the outside:
Like This on the inside:
This is where the project is so far:
Condenser with the original filter zip tied back on to help keep it cleaner.
Relocated evaporator. This will sit in a water bath. It is 90° from where it originally was.
October 3, 2014
Does it have anything to do with fraking? no, it just measures the specific gravity of liquids. More specifically from 0-32° of brix. The guy who was selling it had no idea what he was selling so I got it for $25. Nearest Atago model I can find is about $180, so I win!
It seems to made out of one piece of machined aluminum and very good optics. it reads the output in Brix instead of SG, which is a little less ideal, but I can make a cheat sheet to convert. It reads in 0.1° steps, so I think it will be accurate enough.