Coldbreak Brewing Giveaway - Winners Drawn!

Home Brew Forums > Home Brewing Beer > Electric Brewing > Got stuck on my electric setup.. need advice
Reply
 
Thread Tools
Old 09-17-2012, 01:48 PM   #1
Sublime8365
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2011
Location: Houston, Texas
Posts: 131
Liked 1 Times on 1 Posts

Default Got stuck on my electric setup.. need advice

Ok so I started down the path to a partial electric setup here:

http://www.homebrewtalk.com/f51/look...oach-s-350658/

Well I didn't do my research properly and discovered (luckily, the easy way by stumbling across it on the forums) that the Johnson A419 is only rated up to 15 or 16 A, which is not enough obviously if my 2000w element is pulling 16.3 A.

The way I see it, I have 2 'easy' options here:

1.) Buy a 1500w element that will work with my Johnson A419 and save the 2000w element for a rainy day when I can try to go full electric. My 2 questions here are: should the 1500w element be strong enough to maintain my mash temps at 154? I would think so (I'm not that worried about how long it will take to get up to that point, I can always heat with my propane burner, I'm really only worried about the mash temps). Also, if I try to go full electric, will 2000w be enough to maintain a rolling boil? I usually have 6.5-7 gallons at the start of my boil. Again, I am fine with using the stove and the element to get it up to boiling, but would really like to only use the element during the boil. Can this be done?

2.) Buy a PID that can handle the amps from the 2000w element. I plan on converting a mini fridge into a ferm chamber anyway so my johnson A419 wouldn't go to waste, but I had hoped to just use the controller for both purposes.

I'd prefer to go with option 1 if it will work out. What do you guys think?


Sublime8365 is offline
 
Reply With Quote
Old 09-17-2012, 03:40 PM   #2
wyzazz
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2009
Location: Atwater, OH
Posts: 4,289
Liked 48 Times on 45 Posts
Likes Given: 79

Default

I think to control an electric element you will be much happier purchasing a PID controller and using that in conjunction with an SSR. Just my opinion, but the way the PID's control elements is a much better solution than using a standard temperature controller. Maybe look at building a little RIMS tube?


__________________
Quote:
Originally Posted by Revvy View Post
And I'd like to see my 1.080 beers ready from grain to glass in a week, and served to me by red-headed twin penthouse pets wearing garter belts and fishnet stockings, with Irish accents, calling me "master luv gun," but we can't always get what we want can we? :)
wyzazz is offline
 
Reply With Quote
Old 09-17-2012, 06:21 PM   #3
porcupine73
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2012
Location: Fort Meade
Posts: 811
Liked 47 Times on 43 Posts
Likes Given: 513

Default

You could add an SSR and then use the A419's relay contact to provide some low voltage DC power say from an old cell phone transformer to the SSR, which would then control your heating element. Or an interposing relay. If you don't have a lot of thermal mass in the heating element, which it probably doesn't, it shouldn't overshoot too much.
porcupine73 is offline
 
Reply With Quote
Old 09-18-2012, 03:02 PM   #4
zeus53219
Feedback Score: 2 reviews
Recipes 
 
Join Date: Oct 2010
Location: Milwaukee
Posts: 294
Liked 7 Times on 6 Posts

Default

Quote:
Originally Posted by Sublime8365 View Post
2.) Buy a PID that can handle the amps from the 2000w element. I plan on converting a mini fridge into a ferm chamber anyway so my johnson A419 wouldn't go to waste, but I had hoped to just use the controller for both purposes.
There are no PIDs with internal relays that can handle that amperage(2000w=16A @120v). Most are rated for 2-3A. You would need a SSR or a contactor that your PID would control.
zeus53219 is offline
 
Reply With Quote
Old 09-18-2012, 04:15 PM   #5
Sublime8365
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2011
Location: Houston, Texas
Posts: 131
Liked 1 Times on 1 Posts

Default

Thanks everyone for the input!

I'll definitely invest in an SSR.

porcupine - I think I'm going to look into your suggestion first because it allows me to avoid purchasing a PID for the time being. What type of volts/amps should I be looking for in an old cell phone charger? What would be the potential disadvantages of doing this versus a PID?

Thanks!
Sublime8365 is offline
 
Reply With Quote
Old 09-18-2012, 05:07 PM   #6
porcupine73
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2012
Location: Fort Meade
Posts: 811
Liked 47 Times on 43 Posts
Likes Given: 513

Default

Whatever voltage range your SSR would accept. Most seem to say 3VDC to 32VDC. Pretty much any wallwart, old cell phone charger, etc will fall into that range. The SSR's don't need a ton of current to fire, a cell phone charger would have plenty of current available. You do need the heat sink with your SSR though.

With a PID you will get better control basically IF it is tuned properly. You can get less temperature variation and it can be tuned to pretty much eliminate overshoot if it is tuned to the system. The Johnson is simply an on/off linear controller based on the setpoint with what appears to be basically a hysteresis option, it does not use PID control. But with the Johnson you could probably still maintain the temperature within about 3 deg F range.
porcupine73 is offline
 
Reply With Quote
Old 09-18-2012, 11:44 PM   #7
Sublime8365
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2011
Location: Houston, Texas
Posts: 131
Liked 1 Times on 1 Posts

Default

Thanks. Would I need a heat sink with the SSR regardless if I go with the PID or Johnson Control.

And when you say within 3 degree range, do you mean +/- 3 (eg 151-157 degrees) or +/- 1.5 (eg 153-156)?
Sublime8365 is offline
 
Reply With Quote
Old 09-18-2012, 11:51 PM   #8
wyzazz
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2009
Location: Atwater, OH
Posts: 4,289
Liked 48 Times on 45 Posts
Likes Given: 79

Default

Quote:
Originally Posted by Sublime8365 View Post
Thanks. Would I need a heat sink with the SSR regardless if I go with the PID or Johnson Control.

And when you say within 3 degree range, do you mean +/- 3 (eg 151-157 degrees) or +/- 1.5 (eg 153-156)?
You will need a heatsink for the SSR either way.

If you set your mash temp for say 155F you could have a variance down to 152-158. 3F in either direction from your mash temp.

FWIW, I'd recommend a PID. They are much more accurate and you will save time and frustration in the long run doing this the "correct" way the first time.
__________________
Quote:
Originally Posted by Revvy View Post
And I'd like to see my 1.080 beers ready from grain to glass in a week, and served to me by red-headed twin penthouse pets wearing garter belts and fishnet stockings, with Irish accents, calling me "master luv gun," but we can't always get what we want can we? :)
wyzazz is offline
 
Reply With Quote
Old 09-19-2012, 12:03 AM   #9
Sublime8365
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2011
Location: Houston, Texas
Posts: 131
Liked 1 Times on 1 Posts

Default

Yeah it sounds like the PID is the way to go here.

I'm looking at buying the following unless you have recommendations for better/cheaper alternatives:

http://www.auberins.com/index.php?ma...products_id=77

http://www.auberins.com/index.php?ma...products_id=30

http://www.auberins.com/index.php?ma...&products_id=3
Sublime8365 is offline
 
Reply With Quote
Old 09-19-2012, 12:04 AM   #10
porcupine73
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2012
Location: Fort Meade
Posts: 811
Liked 47 Times on 43 Posts
Likes Given: 513

Default

I'm just estimating a three degree range with the Johnson based on how I have seen my behave. I am not saying it would be +/- 1.5. I think it would be more like +2 -1. Depending on how you set it up, it will come on above or below the setpoint, but the idea being it does not turn off until it reaches at least the setpoint, and then there is a bit of a delay time in it sensing the temp, so generally the temp it senses will continue rise a bit after it turns off, especially if the heating element has a lot of thermal mass (not likely the case here). It's just the response of the system. The Johnson is simple on/off control. Most of the PID's have a tuning sequence. Essentially it is analyzing the step response of the system, and if it is LTI (linear time invariant) which something like this would be, then it has a model of the system and can control it very accurately because in effect it can predict what will happen in the future based on the output it has been giving and the error signal.


porcupine73 is offline
 
Reply With Quote
Reply


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Electric BIAB setup - complete! Psych Electric Brewing 39 01-07-2014 03:17 PM
Simple Electric setup Amity Electric Brewing 4 08-07-2012 03:44 AM
professional electric setup somecanadian Electric Brewing 5 05-18-2012 05:39 PM
electric biab setup cpankonien Electric Brewing 8 05-05-2012 12:20 AM
Electric Setup - Help Appreciated tre9er Electric Brewing 16 02-24-2012 02:54 PM


Forum Jump

Newest Threads

LATEST SPONSOR DEALS