Voltage Drop - Can't get my eBIAB system to boil

[jybingbrew]

I'm trying to troubleshoot why my eBIAB system can't get a rolling boil for about 4 gallons of water. I'm using a ~14 in wide pot with a 2000W element plugged into 110v eBIAB build found on this site.

https://www.homebrewtalk.com/f170/110v-recirculating-ebiab-2-5-gallon-batches-341219/

I've insulated the kettle, but still can't get anything other than a small light boil.

I knew something was up when I couldn't get a 15 amp circuit to trip (as a test), since a 2000W should be drawing more than 15 amps -- so I decided to test a few things.

When I test the voltage out of the back of the control box it is 122.8 Volts. When I test it at the element itself, it drops all the way to 107 Volts when it's on. The resistance of the element is 7.7 ohms.

If i'm calculating properly, i'm only getting 1500W of power our of my 2000W element because of this.

I would expect some level of voltage drop while it's powered and using the SSR, but isn't that quite a steep drop? Or is this normal? The cord for the element is 14awg so I don't think that is limiting the current.

Out of ideas, so any help would be appreciated!

 

[Rivenin]

if you have a 2000w element, you should have 12AWG. What diid you wire everything else with in the box? and what are you getting at the SSR before the element?

 

[jybingbrew]

Everything in the box that would have either pump or element current flowing through it is using 12awg.

I thought 14awg could handle up to 20amps of current ok for short periods of time? I know for safetly, continuous load should be 12awg, but thought 14awg still had the capacity - am I mistaken there? I can rig up a new 12awg cord to see if that helps.

I'll check it at the SSR tonight - was nervous enough frying myself by measuring the element while it was on, so was trying to avoid having my box open while it was on.

Sounds like my assumption that a 15 volt drop is excessive is correct?

 

[atoughram]

Sounds like my assumption that a 15 volt drop is excessive is correct?

Yes - Auber 40a SSR's are rated at 1.6V drop @ 25C (Not sure what SSR you have) - check for loose connections while you're in there.

 

[jybingbrew]

Yeah, am using that Auber SSR.

The good news is that I've gotten the voltage drop down to be almost nothing -- ~3 volts from wall to element, which I think is reasonable. I just replaced my 14ga cord for the element with 12ga and that seemed to take care of it. The cord must have been restricting the current.

Bad news is I still can't get to a rolling boil. I measured my pot again and it's 13.5in, which doesn't seem THAT wide to me.

I'm assuming there's no use checking all the connections again since the element measures a resistance of 7.7 ohms and the voltage is at 118v, I should be getting ~1800W of power which based on others I've seen should be enough.

Anything else I could be missing?

 

[atoughram]

Hmm... Even if you had the whole 120V at the element, it would only be another 70 watts..

Are you circulating while trying to boil?

Lid is on the kettle? I see you have it insulated.

 

[Rivenin]

That was going to be my other suggestion.
While it's going to come up to a boil, keep the lid on and watch the temps, even if you know it'll boil it'll save energy, just while it is boiling leave it off see if that helps at all.
Even on my 3000w setup (2x1500w) this is what a boil looks like, it's not fierce, but that is about 7 gallons or so. Usually when it hits 200 or so, it slows down considerably and prolly takes another 20 minutes to get to a boil. so i'd say be patient, throw a lid on for a bit and see if it helps, even let it run for 30 extra minutes.

(so this is starting out with almost double your volume and just 1000w more, so your setup will completely work, just be patient )

so id say just be patient, toss a lid on, even just 30 extra minutes and see if it'll slowly crawl up. 120v is very slow when it comes to brewing

 

[jybingbrew]

Thanks everyone, appreciate all of the advice. Agree that there's not really much left to get out of it and based on both Rivenin's picture above and posts in the other posting for the 110v build it sounds like I should be ok, even with a weaker boil.

One way to find out! Going to give it a shot and see how it turns out.

 

[kevreh]

Are you sure your not using an element rated for 220v? If so, and my math is correct, your only using 500w.

Testing a circuit by overpowering it isn't a good idea. You could fry the wires in the walls if the circuit breaker fails and doesn't trip like it should.

 

[dyqik]

Are you sure your not using an element rated for 220v? If so, and my math is correct, your only using 500w.
.

The stated resistance of the element shows that it's not a 220V element - 7.7 ohms gives 1870W at 120V, 1570W at 110V.

 

[wilserbrewer]

How many gallons is the kettle?

 

[jybingbrew]

Following up here, I did try a batch and was really surprised what a difference actual wort made. The boil was nice and rolling and worked well. I am not sure why it was so much less with just water, maybe the sugars helped retain the heat and slow down the heat loss?

I appreciate everyone's suggestions on here. I do think the tweaking helped, as I was definitely not getting the full wattage originally.

 

[wilserbrewer]

How many gallons is the kettle?

Glad you had success, I'm curious how many gallons is the kettle?

 

[jybingbrew]

It is a 9 gallon kettle, so overkill for my 2.5 gallon batches, but I was trying to reuse what I had to minimize costs of switching to electric.

 

[creekrat]

I knew something was up when I couldn't get a 15 amp circuit to trip (as a test), since a 2000W should be drawing more than 15 amps -- so I decided to test a few things.

The problem with this thought is that breakers operate on a trip curve. If you run a 15 amp breaker at 16 amps it will take far longer to trip than if you ran it at 20 amps. Every time a breaker is tripped the trip curve is shortened until one day the breaker struggles to operate at the rated load. Also, don't ever run 20 amps on a 14awg wire. You run the risk of burning the wire in 2 somewhere in the wall and catching your house on fire. The 14 awg wire is capable or rated to carry the heat produced by the 20 amp load.

 

[wilserbrewer]

The 14 awg wire is capable or rated to carry the heat produced by the 20 amp load.

I think you mean....

The 14 awg wire is NOT capable or rated to carry the heat produced by the 20 amp load.

 

[Brumateur]

Technically 14AWG wire is capable to carry 20Amp. But it's against a code because in some circumstances wire can generate enough heat to damage insulation.

 

[Rivenin]

Technically 14AWG wire is capable to carry 20Amp. But it's against a code because in some circumstances wire can generate enough heat to damage insulation.

it could and can carry it... however i wouldn't do it longer than a few minutes and surely not for the duration of heating water and boiling.

 

[lschiavo]

You never mentioned the length of the element conductors. Voltage drop is a function of wire size, current and conductor length. I doubt you would be melting any insulation drawing 17A on 14awg. There is a huge safety factor built into conductor ampacity ratings. I am not suggesting that anyone should undersize their wiring but you would have to be hundreds of feet from your source to element to see that kind of drop. You probably fixed a bad connection when you swapped for the #12.

 

[creekrat]

I am not suggesting that anyone should undersize their wiring but you would have to be hundreds of feet from your source to element to see that kind of drop. You probably fixed a bad connection when you swapped for the #12.

NEC ststes that you have to increase the conductor size if the run is longer than 200' as to account for voltage drop

 

[kal]

Following up here, I did try a batch and was really surprised what a difference actual wort made. The boil was nice and rolling and worked well.

Sorry I missed this thread but this is the reason - I get emailed every day from brewers stating that they can't get their first electric test batch with water to a rolling boil and the solution is to use wort instead. Large volumes of water simply do not give a rolling/vigorous boil.

Kal

 

[jybingbrew]

Yup, I should have just tried it out! Though I am glad I went through the troubleshooting a bit, I think I solved some other things in the process and learned a few things from the thread.