Boot Strapped Electric Kettle

[Chanman]

Currently I am fabricating an electric kettle from a dairy tank. The vessel is 7bbl and plan to have 3 15kw low density elements from Brewmation/wattco. My hang up is the controller, i'm looking to spend the least amount possible to get this thing running. I was quoted over 17k for a brewmation barebone control panel, which in my opinion is way too much.
My other idea is to set up 3 circuits with 3 manual switches and just turn 1 or 2 off if needed to maintain a boil.
I don't have a lot of experience with electric brewing so I am wondering if having 2 elements on during boil @ 100% would lead to any issues (mainly scorching). I realize that 2 elements could be not enough and three could be too much but im willing to gamble. I have read that it could be wise to recirculate with a pump when you turn on the elements to prevent scorching. I'm not sure if that's valid but an easy issue to remedy so im not too worried about that.
I would just like to figure the issue out with the elements before I get too far into it.

Thanks!

[aaroncpack74]

We added a switch to take us off 220v down to 110v on a still to help reduce on/off fluctuations and reduce overtemp situations.

Honestly don’t remember how exactly but it really helped improve temperature control.

[brain medicine]

we manage to boil about 80 gals with 10.5kw, in a steel drum with nothing but a few wraps of reflectix as insulation, and the lid until it hits boil. so frankly that seems a bit overkill to me. at the same rate you'd be looking for 36kw. 45 is alot.

you've gotta have some decent current to generate that much heat, are you single phase or 3phase?

in theory it shouldn't matter as the principle is the same, but you can build your own controller fairly easily. you need a PID type controller for each element to control the power level. a relay for each element's hot leads, heat sinks for each of those relays, a big ass box to stuff it all into and hopefully even a fan in there to cool it all down. and a kill switch for emergency shutoff.

that's your best bet if you're worried about scorching. cuz if that's your concern, its better to have all three elements running at 60% power vs two elements at 100% and one at zero.

no idea how much those parts will cost at that size, but i wouldnt just buy the cheapest ones you can find either. and if its not already something you know, using three phase is best if you have it, your parts and wiring will be cheaper as they'll be lower in amperage than using 240 single phase.

[John@Brewmation]

Hey Chanman,

This is John with Brewmation, and thanks for considering us for your controls. I completely understand that every project is on a budget, so we're happy to set you up with just the elements if you feel you can engineer the controls. I would, however, suggest trying to avoid an on/off design that will only send 0 or 100% to the elements. Our controls are designed to allow you to adjust power from 0-100% at any increment, which is the best way to ensure a steady, consistent boil without wasting power and sending more power/heat than is needed to achieve and maintain a boil.

We recently did a webinar on this that might be of interest to you (particularly around the 19:40 mark). Coincidentally, this example uses a 7BBL setup with 3x15kw elements to discuss the differences between on/off and 0-100% controls:
https://www.brewmation.com/post/webi...p-your-brewery

As far as a recirc pump goes, we haven't found this to be necessary, especially with properly controlled elements. There will be enough movement of the wort from the boiling to prevent the wort from stagnating around the elements.

One last point is that our controls are UL listed (we do this in-house, so it's not a significant expense), which not only best practice for the safety and protection of your equipment and brewer, but that your electrical inspector should look for. We've heard stories of openings being delayed because their inspector wouldn't sign off on unlisted controls.

Let me know if you have any specific questions!

Cheers,
John