Hybrid controller

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gwizard
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Location: AUS

Hybrid controller

Post by gwizard »

So, this is my take on custom built controller.
It's been about 30 years since the last time I soldered, but having those electrical engineering lessons in senior school paid off :D

The basic kit is Stilldragon large, with Inkbird 106vh pid, digital amp/volt/watt display and an AC 80mm fan.
This controller is dual purpose. On one end, you can use it in distilling mode, controlling via the POT.
On other hand, you can use it in mashing mode, controlling via the pid.

Inside is an SSR serially connected to SSVR. SSR is controlled by the pid, while SSVR is is controlled by the POT.
For distilling, I set pid in manual mode and use the knob to control the output. For mashing, I set knob to 100%, set pid to auto and set my temp.
There is a temp probe connector on top of box from pid.
For safety, I've also put a socket with a fuse, and a thermal cutoff switch connected to one of the heatsinks, set for 60C. So, if at any point internal temp is higher then 60C, it will cutoff load completely, but leave fan operating so system is cooled back down. This is a precaution for the harsh Australian summer, where we often have above 40C ambient.

Front
2020-07-26 15.40.35-1.jpg

Back
2020-07-26 15.40.56-1.jpg

Diagram
unnamed.png
unnamed.png (11.57 KiB) Viewed 2017 times

Constructive criticism is welcome.
NineInchNails

Re: Hybrid controller

Post by NineInchNails »

I see you have a fan either blowing air into the box or drawing air out of the box. Do you have another port for air to enter/exit? If not then the fan won't be that effective because the box cannot have flow through air exchange. You can also install the fan on the interior of the box to make it more compact. It doesn't have to be on the exterior of the box to function.

My controller is much like yours only I installed a 3 position selector switch PID/Off/Variable. I can select PID for mashing, variable for distilling and off. It makes operation very convenient.
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gwizard
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Re: Hybrid controller

Post by gwizard »

Fan is extracting and I have vent holes at the bottom, with some anti dust mesh glued.
Hot air naturally rises to the top, so cold air enters at the bottom, sweeps across both heatsinks and exists at the top. That's same design as used in PC cases.

I thought about putting a 1-2-3 switch, but to be honest I barely have enough space in the box as it is, cause heatsinks are massive, and the wiring is complex already. But yeah, it is quite convenient. Maybe a future mod.
NineInchNails

Re: Hybrid controller

Post by NineInchNails »

gwizard wrote: Tue Jul 28, 2020 7:35 am Fan is extracting and I have vent holes at the bottom, with some anti dust mesh glued.
Hot air naturally rises to the top, so cold air enters at the bottom, sweeps across both heatsinks and exists at the top. That's same design as used in PC cases.

I thought about putting a 1-2-3 switch, but to be honest I barely have enough space in the box as it is, cause heatsinks are massive, and the wiring is complex already. But yeah, it is quite convenient. Maybe a future mod.
Yes it is a significant amount of additional wiring for that switch, but super convenient. I somewhat recently built a 120V controller using an Auber EZboil and it's a fantastic little unit. It's a fraction of the size of my previous controller very much like yours and just yesterday I finished a simple 240V box with 40A SSR & heatsink controlled by the 120V EZboil. Now it can be used for 120V and 240V as PID or variable. Building controllers is addictive.
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gwizard
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Re: Hybrid controller

Post by gwizard »

I will leave this here for all future Aussies that decide to use Amp/Volt meter from Jaycar, also known as Powertech QP2325.
https://www.jaycar.com.au/ac-power-mete ... d/p/QP2325

It's wiring diagram, as noted in the manual, is misleading.
image.png

I've blown 2 fuses before I got the sense to open its rear panel and find out the real model, which is PZEM-021.
So, the correct wiring of this meter is:
image.png
Please don't make the same mistake I did, wire it correctly.

Note 1: Since this meter is wired after the SSVR (look at the diagram in posts above), it will dim and shut off when you switch your rheostat to 0%.
Note 2: When you test with a light bulb, which is a resistive load, it will NOT turn it off completely. A true test, with inductive load, a kettle or an iron, will correctly turn it off when at 0%.

Век живи, век учись
Tennessee_Spirits
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Location: Memphis Tennessee

Re: Hybrid controller

Post by Tennessee_Spirits »

I really like my PID and PWM controller combined, which is the same setup. For the PWM I am using a small square wave generator to drive a SSR in parallel with the one driven by the PID. Optical isolators in the SSR protect the control circuits.

Modern electronics, much of it from China has changed the modularity for all of us. I could build a square wave circuit easily as it is an astable multivibrator and vary the RC values to change the percentage of on time. But the $14 Chinese made module has digital display of the on time percentage so I can precisely set the PWM heating at low cost. And this unit costs less than adding a clamp on ammeter.

Most of these 40 AMP SSRs are zero crossing devices and I see drawings with a potentiometer connected to the control terminals. Is this all that is necessary? Usually light dimmers have a RC network that turns on the triac and the control varies the turn on point on the power sine wave. This produces the radio noise that in part has made AM radio useless.

One advantage of zero crossing device SSRs (which are common too) is the low amount of radio frequency noise they generate. But to give good control the frequency of switching needs to be set low so it will turn on the device long enough to have predictable heating effects. I run this square wave controller at 100 Hz, its slowest range.

I don't have a clamp on ammeter in my design so it does not spot a burned out element or a bad connection. My controller is getting crowded enough that I did not add this, but I can appreciate the value of a design that monitors power actually consumed.
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Yummyrum
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Re: Hybrid controller

Post by Yummyrum »

Tennessee_Spirits wrote: Thu Aug 13, 2020 3:31 am I run this square wave controller at 100 Hz, its slowest range.
This sounds a bit weird . I would have thought you would run it at around 1Hz so you can have some control.
100Hz is only half a cycle ( on our 50Hz mains) .
Or are you meaning that 10mS is the minimum duty cycle it will do ?

At 1Hz , you can adjust 0-100% in 1% steps on 50Hz mains .
Tennessee_Spirits
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Re: Hybrid controller

Post by Tennessee_Spirits »

Astute of you to notice that. It is the slowest rate the unit does but it provides fine control of heat output and is completely reproduceable.
Johnnywhiskey
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Re: Hybrid controller

Post by Johnnywhiskey »

NineInchNails wrote: Tue Jul 28, 2020 6:08 am
My controller is much like yours only I installed a 3 position selector switch PID/Off/Variable. I can select PID for mashing, variable for distilling and off. It makes operation very convenient.
This is the way I have my controller setup also--3-way selector PID/Off/Variable. Mine is switched through contactors (similar to air con contactors) since I'm not sure if there is are reasonably sized 3-way selectors that can handle ~21amps.

A problem with running the SSR and SSVR in series is that the amps are continuously running through SSR, which I've found can get pretty hot when run continuously. A three-way switch lets you cut it out of the circuit.

Best, JW
seabass
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Re: Hybrid controller

Post by seabass »

They make them and aren't too expensive, but are massive. The one I got is a 63amp.
And it's bulky as hell.
batch97
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Re: Hybrid controller

Post by batch97 »

Is this basically the same as one of the EZBoil controllers, except broken out into two separate controllers? I like the flexibility your setup provides. And I think (novice here) the EZboil seems to combine the two into one nice small package.
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