30 Amp Homer Box, 3 PID, 2 Element

[ryanhope]

Homer boxes are cheap as hell and much easier to work on than aluminum so I figured I would use one for an initial test control panel (box) build.

Contents:
3x Watlow 96 PIDs
3x 40A contactors
1x 25A SSR (will upgrade to 40A soon)
1x 12V transformer (for arduino mini pro & rpi not shown)
1x Key main switch
2x Illuminated pump switches
2x Element LEDs
1x 3way element selector
1x Estop (not shown)

All of the PIDs, in addition to primary sensor input and SSR output, they have an additional output which can be set to report process value or percent power. They also have an extra input which can be use for remote set points. Thats where the arduino and rpi come in. The aduino will handle all of the A/D conversion and the rpi will run some remote monitoring and control software I write.

For those who are interested, I mounted all the components to 1/4" MDF. A piece with the dimensions 7"x16" fits perfectly.

 

[iijakii]

Lookin good! So what do you have in mind to do with the RasPi?

 

[ryanhope]

Lookin good! So what do you have in mind to do with the RasPi?

Initially just data logging and manual remote set points but maybe down the road mash profiles and automation.

 

[ryanhope]

It's alive!

 

[doug293cz]

You might want to think about putting a temp probe on your SSR. That heatsink, mounted to MDF, in a closed plastic box, isn't going to be doing much cooling. Typical high current SSR's can dissipate 30 - 35W (at spec max forward voltage drop and ~20A current.) You want the SSR (at SSR/heatsink interface) to be less than 140°F (60°C), and lower is better.

Brew on

 

[ryanhope]

You might want to think about putting a temp probe on your SSR. That heatsink, mounted to MDF, in a closed plastic box, isn't going to be doing much cooling. Typical high current SSR's can dissipate 30 - 35W (at spec max forward voltage drop and ~20A current.) You want the SSR (at SSR/heatsink interface) to be less than 140°F (60°C), and lower is better.

Brew on

Good point about the temps. I never planned on running this completely closed. I forgot to mention that I have a fan that I am planing on mounting on the side of the box next to the SSR.

 

[augiedoggy]

Instead of changing the 25a ssr which is rated for and fine for your application, I would invest in a 12v fan and $3 12 power supply to power it. I would mount it to blow thru the heatsink. I did this myself and have had no issues with my 25a ssr in 3 years... BTW its only speculation that the 40a ssr will run cooler or more reliably than a 25a one for a 17-23a load depending on your element. I have seen no evidence that anyone has done as testing to show this... Only that it's assumed.

 

[ryanhope]

Instead of changing the 25a ssr which is rated for and fine for your application, I would invest in a 12v fan and $3 12 power supply to power it. I would mount it to blow thru the heatsink. I did this myself and have had no issues with my 25a ssr in 3 years... BTW its only speculation that the 40a ssr will run cooler or more reliably than a 25a one for a 17-23a load depending on your element. I have seen no evidence that anyone has done as testing to show this... Only that it's assumed.

If you notice, I already have 3amp 12v power supply in there to do things like power 12v computer fans

 

[augiedoggy]

If you notice, I already have 3amp 12v power supply in there to do things like power 12v computer fans

ah I missed the transformer...

 

[BrunDog]

Make sure that wood piece is glued/screwed down. An accidental tip over could cause things to move and contact to be made in undesirable ways.

-BD

 

[ryanhope]

Last night I did my first 100% electric brew. The Homer box help up nice, no issues what so ever. Did a variant of Dennys Wry and ended up hitting 90‰ efficiency.

View attachment 1446988647221.jpg

 

[ryanhope]

Added a 6" 12v fan over the SSR.

https://youtu.be/ayQdiZ9V1W4

 

[WI_Wino]

what amp meter/voltmeter are you using?

 

[ryanhope]

what amp meter/voltmeter are you using?

Something cheap I found on eBay back when I was looking for STC1000s.

 

[WI_Wino]

Does it use a shunt or a coil like this one: http://www.amazon.com/dp/B00DVH64HW/?tag=skimlinks_replacement-20

 

[ryanhope]

Does it use a shunt or a coil like this one: http://www.amazon.com/dp/B00DVH64HW/?tag=skimlinks_replacement-20

What you linked to looks like exactly what I have. Works great.

EDIT: Amazon history stays that exactly what I have.

 

[WI_Wino]

sweet, thanks!

 

[BrunDog]

I am sorry... I just don't get it. You are building a nice system with decent components. Why did you cheap out on the enclosure? A legit enclosure would not set you back much in terms of your total spend. Just my opinion, take it for what that is.

 

[ryanhope]

I am sorry... I just don't get it. You are building a nice system with decent components. Why did you cheap out on the enclosure? A legit enclosure would not set you back much in terms of your total spend. Just my opinion, take it for what that is.

There are a lot of answers to your question:

1) This was really just a temporary solution to test 1 PID but since I don't know what I want to use for my final enclosure yet I added more components to make it usable while I ponder my many options.

2) I haven't brewed in a year, been siting on a pile of parts for a while, just wanted to get something working and some brews under my belt with all electric before I spent more on an enclosure.

3) I rent, having a solution that is easy to break down and move is nice. I think I can fit my entire brewery in my car.

4) I don't like how massive some of the panels are that I see, I'm not crazy about the bulky vertical mount cabinets. I don't really have any place to hang a giant panel since I am a renter. I am learning toward a horizontally mounted rack mount amp chasis which I will mount under my brew table.

5) Cutting/drilling orange plastic is way easier than aluminum.

 

[BrunDog]

Fair enough! For temp work - it makes total sense.

-BD