raspberry Pi driven 3 keggle eHERMS build thread (slow build, with lots of questions and tangents)

[Thedutchtouch]

so... i figured it's about time for a build thread. i'll be adding to this as i go along, and it'll be a slow build, due to a number of factors including a toddler and infant at home, waiting for parts to come in (some from China, some waiting for items to get back in stock) but wanted to at least get started compiling it in the same place. i'll edit this post to include links to build steps if the thread becomes too cumbersome. i'd like to start out by giving a big thank you to members that have posted build threads before and answered my many questions in other threads.

Here's my setup and plan as it stands: I don't have a brew room or area, my cellar won't work and i'm tired of brewing outside. therefore i'm going electric, and designing my system to be plugged in to the 30A receptacle that the dryer runs off of (i recently replaced my 140 year old house's 3 wire receptacle with a 4 wire when i upgraded the washer/dryer, so have true 220v w/ground and neutral. I'musing a 50a GFCI spa panel to add in the GFCI protection, and have designed a controller/panel that will use a raspberry Pi as it's brain, and control 2 elements (one at a time), and two pumps, for an eventual 3 vessel HERMS setup. the HERMS component will likely be the last part added, and this all replaces a propane (banjo burner) BIAB setup using a bayou classic and a voile bag i sewed up myself. I also currently only have one pump, the second will be added with the upgrade to HERMS, but i'm designing the controller for 2 in preparation for that future step. I've also decided to use a 7 inch capacitative touch screen for my main rPi interface, but will be using a main power switch/contactor for safety, as well as switches and contactors for the pumps and elements to ensure that i can only have one element on at a time, and to be able to either control the pups with the raspberrry pi, or in manual mode (for cleaning cycles or redundancy)

hopefully that's enough of an overview, I welcome any/all feedback and questions (and PLEASE post if it looks like i'm doing something wrong!), and i'll link individual build steps/components below.

Spa Panel (GFCI protection)
Initial control panel layout

 

[Thedutchtouch]

spa panel wiring and setup

I decided to use a 50a spa panel for GFCI protection, and because i'm not planning on being in this house forever so want something i can easily take with me, compared to replacing the breaker in my main panel with a GFCI breaker. i got away with doing some work on the dining room table, because the tablecloth had already been destroyed by our 2 year old lol. I used an appliance whip for the input side, and a length of 10/4 SOOW cable for output (i'd acidentally bought this instead of 10/3 for the elements, so figured i'd give myself the flexibility to brew up to 20 feet from the outlet, letting my choose laundry room, kitchen, or first floor bathroom). I also used compression fittings meant for conduit in order to run the cable in to the box... I couldn't find a better option that fit the SOOW cable. I'm planning on wrapping the compression fittings with electrical tape, or using liquid electrical tape/silicone to fully waterproof them, but it's working well to hold the cables in place for now. the 10/4 cable was attached to a NEMA L14-30 female plug, which'll fit into a male receptacle on the main box. i also wrote on the spa panel to remind myself/ any future users that it's wired for 30A even though it's a 50A breaker. photos below.

 

[Thedutchtouch]

Enclosure Layout/design

My Yuco 16x16x6 enclosure came today, and I started laying out the components.

This is just a quick draft version, i didn't measure or mark anything. back plate is covered in blue painters tape for when i DO start setting the final layout, wanted to get some feedback and double-check the raspberry pi and power supply outlet dimensions before doing any drilling as my initial computerized layout may not end up being the final draft.

Here is a draft layout, the open space in the center top left is where i'm thinking the rPi and outlet will fit. i shifted the SSR heatsinks a bit towards the center to keep them further from the element receptacles.

And the external potential layout. the two way switch at the top/left (under the touchscreen) is main power, which will be hooked to a contactor, which in turn will control the two hot legs of the main power input. the element selector switch is a 3 way switch so that only one element will fire at a time each ON pole will be wired to a contactor that'll control the HLT and BK element feeds, so that way even if the SSR is activated by the raspberry Pi, the element will not be supplied with power unless the appropriate contactor is being energized by the switch. The red 220v LEDs will let me know if that element is on (not just that it's selected, as the position of the switch will tell me that). The blue 110v LEDs correspond to pumps, each will have a 3 way switch, for auto, off, and manual, so that they can be either controlled by the Pi (auto mode through a SSR) or manual on. the LED's will again correspond to pump on/off, regardless of if it's due to the manual or auto mode. i elected to not use a contactor for the pumps, as the current draw should be fine for going directly through the switch
safely

this last picture is just of one of the LED's sitting on top of a contactor with the lid closed, to show how much extra space will be between the lid mounted and back plate mounted electronics, should have plenty of room since there's a space above the LED, and 1/3 of it will be on the outside of the case anyway.

 

[golfindia]

I would put heat sinks outside the box, and just use one or Maybe 2 large ones. Those tiny ones don't do much. Also, if you put a Pi in that box with all of those heat sinks, the system temp is going to get critically high, and you may have stability issues (I have a 65w DC PS inside My enclosure). I had to add a dedicated Pi fan after the fact for this reason. Touch screen: I had crashing issues when I tried to run a display on my Pi system. I just use an old Kindle over the LAN, and I can walk around and monitor what's going on. A velcro tablet mount on the front of the box.....? But, to each their own, which why this is so much fun....

Edit, switches: wiring the Pi power independent of everything else is a good idea, so you don't have to have a live box to fiddle with the computer.

 

[Thedutchtouch]

I would put heat sinks outside the box, and just use one or Maybe 2 large ones. Those tiny ones don't do much. Also, if you put a Pi in that box with all of those heat sinks, the system temp is going to get critically high, and you may have stability issues (I have a 65w DC PS inside My enclosure). I had to add a dedicated Pi fan after the fact for this reason. Touch screen: I had crashing issues when I tried to run a display on my Pi system. I just use an old Kindle over the LAN, and I can walk around and monitor what's going on. A velcro tablet mount on the front of the box.....? But, to each their own, which why this is so much fun....

Edit, switches: wiring the Pi power independent of everything else is a good idea, so you don't have to have a live box to fiddle with the computer.

Thanks for the feedback, I was debating wiring the pi outlet before or after the main power contactor, but now think I'll go ahead and do it before. This will be the only live connection that isn't through a contactor, but I think it'll be fine since it's all inside the box.

I'm going to do some testing with the heatsinks internally first, but if needed am planning to shift the SSR's to the top of the box with an externally mounted, large heatsink the enclosure already has an opening on top so it's just a matter of taking off the plate and attaching the heatsink, possibly enlarging the opening but that's not too big of a change, and I've got enough extra wire that I can move the SSR's without too much trouble if need be.

As far as the touchscreen goes, do you remember which brand you used? This is waveshare(from Amazon) though from what I can tell it looks like a lot of the touchscreens are all from the same factory and just rebranded. Mainly wanted to get this as an experiment, I am not going to cut the lid for it until I'm positive it works, backup is a previous generation iPad mini with a semi-permanent mount in the same location as the screen is planned. I have it already and haven't used it in a year so... Sunk cost.

 

[golfindia]

Don't remember what kind of screen It was, but cheap. I also tried using the HDMI output for the large TV on my patio. It wasn't reliable either, kept locking up.

One other useful thing I did was put some small Pi controlled relays on the control side (DC voltage) of the heater SSRs. I then set up "virtual" auxillary switches in software that can Shut off the heaters quickly without a lot of clicking around.

The only manual switches I have on my box are for the computer and 1 main contactor

 

[-CHRIS-]

I'm going to do some testing with the heatsinks internally first,

Don't bother, it will not work. You only hope is to install a fan that is directly blowing air across those heat sinks bringing fresh air into the cabinet.

Chris

 

[Thedutchtouch]

Don't bother, it will not work. You only hope is to install a fan that is directly blowing air across those heat sinks bringing fresh air into the cabinet.

Chris

Do you have direct experience with them? most of what i've seen has been anecdotal, or second hand reports... i'm not opposed to getting a different heatsink... just figured i'd get some first hand experience to base it on.

 

[-CHRIS-]

Do you have direct experience with them? most of what i've seen has been anecdotal, or second hand reports... i'm not opposed to getting a different heatsink... just figured i'd get some first hand experience to base it on.

Yes, tried exactly what you are showing. I went to far as to flatten the heatsink and SSR on a surface plate. There is just too much heat generated for those heat sinks to work in a small enclosure. I blew a string of SSRs until I bought a massive heatsink and mounted it externally.

If you have two muffin fans, one bringing fresh air in and blowing across the heatsinks and one blowing out of the cabinet you may have a chance.

Chris

 

[Thedutchtouch]

Yes, tried exactly what you are showing. I went to far as to flatten the heatsink and SSR on a surface plate. There is just too much heat generated for those heat sinks to work in a small enclosure. I blew a string of SSRs until I bought a massive heatsink and mounted it externally.

If you have two muffin fans, one bringing fresh air in and blowing across the heatsinks and one blowing out of the cabinet you may have a chance.

Chris

Well that changes things then. I guess a larger heatsink on the top of the box is in my immediate future. Thanks!

 

[augiedoggy]

so... i figured it's about time for a build thread. i'll be adding to this as i go along, and it'll be a slow build, due to a number of factors including a toddler and infant at home, waiting for parts to come in (some from China, some waiting for items to get back in stock) but wanted to at least get started compiling it in the same place. i'll edit this post to include links to build steps if the thread becomes too cumbersome. i'd like to start out by giving a big thank you to members that have posted build threads before and answered my many questions in other threads.

Here's my setup and plan as it stands: I don't have a brew room or area, my cellar won't work and i'm tired of brewing outside. therefore i'm going electric, and designing my system to be plugged in to the 30A receptacle that the dryer runs off of (i recently replaced my 140 year old house's 3 wire receptacle with a 4 wire when i upgraded the washer/dryer, so have true 220v w/ground and neutral. I'musing a 50a GFCI spa panel to add in the GFCI protection, and have designed a controller/panel that will use a raspberry Pi as it's brain, and control 2 elements (one at a time), and two pumps, for an eventual 3 vessel HERMS setup. the HERMS component will likely be the last part added, and this all replaces a propane (banjo burner) BIAB setup using a bayou classic and a voile bag i sewed up myself. I also currently only have one pump, the second will be added with the upgrade to HERMS, but i'm designing the controller for 2 in preparation for that future step. I've also decided to use a 7 inch capacitative touch screen for my main rPi interface, but will be using a main power switch/contactor for safety, as well as switches and contactors for the pumps and elements to ensure that i can only have one element on at a time, and to be able to either control the pups with the raspberrry pi, or in manual mode (for cleaning cycles or redundancy)

hopefully that's enough of an overview, I welcome any/all feedback and questions (and PLEASE post if it looks like i'm doing something wrong!), and i'll link individual build steps/components below.

Spa Panel (GFCI protection)
Initial control panel layout

I also have an ancient house and found the lack of wall insulation and ballon framing advantageous when running a new 30a 240v line up to a spare bedroom I use as my home brewery... I brew in front of a window with a homemade foamboard hood and dual window fan placed at the top of the window and this works very well, the only downside is having to use the adjacent bathroom for water supply and running 2 hoses to it for chilling but with quick disconnects it works very well for 4 years now. I started with the crappy rex 100 then mypin ta4 then td4 pids and then the ezboil 310 unit before finally jumping to an arduino based brucontrol panel. If you havent given it a good look I recommend doing so before commiting to the pi route...
Good luck!

PS I also use a single pc fan to blow across my heat sinks from the bottom and out a hole in the top of my enclosure..

 

[Thedutchtouch]

I also have an ancient house and found the lack of wall insulation and ballon framing advantageous when running a new 30a 240v line up to a spare bedroom I use as my home brewery... I brew in front of a window with a homemade foamboard hood and dual window fan placed at the top of the window and this works very well, the only downside is having to use the adjacent bathroom for water supply and running 2 hoses to it for chilling but with quick disconnects it works very well for 4 years now. I started with the crappy rex 100 then mypin ta4 then td4 pids and then the ezboil 310 unit before finally jumping to an arduino based brucontrol panel. If you havent given it a good look I recommend doing so before commiting to the pi route...
Good luck!

PS I also use a single pc fan to blow across my heat sinks from the bottom and out a hole in the top of my enclosure..

We are only planning on staying in this house another 3-4 years and I already have tons of renovations that I need to do, so don't want to run 220 anywhere else in this house, but did have quite an easy time moving the 220v service from one side of the laundry room to the other because of this... I mean, the licensed electrician had an easy time because of this . I would also love to add a steam condensing system , but for now will likely be taking advantage of the bathroom window and a top mounted fan, like you do in the bedroom. My house is drafty enough and I have hot water radiator heat so tha brew day here or there won't affect my heating bill too dramatically, and I figure the bathroom is used to handling some steam anyway. I've committed to the Pi route, but am not opposed to switching to an Arduino in the future, or running them in tandem -my early reading is that the Arduino would be better if I want to expand my automation and control fermenting Chambers etc, so an Arduino will likely be in my future, post move if I can work out a dedicated brew space. I've been itching to play with a pi for a while now, and this is a good excuse. Or a good enough excuse lol.

I am really torn between the external heatsink (and maintaining some level of water resistance for the box) or sticking with what I have and trying a fan. Initially I was leaning towards fan, but now am switching gears to external heatsink. I'll have a while to mull it over before final assembly gets underway, so we'll see.

 

[golfindia]

An SSR gives off about 1.5watts per amp that it's switching.

 

[Thedutchtouch]

https://www.amazon.com/dp/B01HMCYV80/?tag=skimlinks_replacement-20

This has been recommended elsewhere. Likely need 2 of them to fit the 4 ssr if i go this route (I realize the pump SSR's won't put out much heat but still want to keep it consistent).

alternatively, http://www.heatsinkusa.com/4-600-wide-extruded-aluminum-heatsink/ seems promising as well. a 12 inch length is 27 dollars, so cheaper than amazon including shipping. fins are ever so slightly shorter but it's almost 3/4 inch wider... which i'd assume is better, more thermal mass... and reviews state 45 watts dissipation in 4 inch section with 25C heat rise, so, i'm thinking we're good to go there.




and while we're on the topic of heatsinks... anyone ever used these on a pi? https://www.amazon.com/dp/B018BGRDVS/?tag=skimlinks_replacement-20 not like i'm overclocking it or anything...