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Apex compatibility with 9A heater?

Chromis

Chromis

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What happens if you plug more than a 7A device, like a 800W heater rated at 9A, into an Apex EB832? Does the Apex fry, blow a fuse (is it reversible), or simply limit current draw to 7A?

The biggest heater I can find with 7A or less is 500W which is not going to work for larger tanks (>130g according to Finnex).
 
Sorry I dont have an answer to your question, but why not instead of using a single large heater use two smaller heaters together?
 
1) I'm betting your odds of burning a contract increase. I highly doubt the Apex will current limit, especially as it would have to do so my decreasing the incoming voltage delivered to your resistive load. I'm not personally a fan of pushing electronics beyond their power ratings, especially in a humid salty environment.
2) You could get an EB8 as those have two outlets rated to 10 amps each. You could also have the Apex trigger a different relay. Personally I think two smaller heaters is a better solution.
3) Do the large heaters you want have internal thermostats or are you just planning to use the Apex? Do you want to bet your tank on that temperature probe never getting dry/falling out of your tank?
4) Power demand is more than tank size it is also what else you are running in the tank, what the air temperature is relative to your desired water temp, and if you have lids or other tank insulation. My 600 has run on 300 watts, but that's with a small delta-t and accepting a couple degree daily temperature swing. Get rid of those and I'm closer to 1000 W during parts of the day.
 
How big is the tank?

My 190g tank +60g sump is being heated by a 500w heater in an uninsulated garage.

c9e51cf3ea43b604bd80c0271e63c666.jpg


That heater draws a max of 3.8A.

It is a Finnex titanium heater.

The tank was actually being heater by a 300w Ehiem from Nov to mid Dec. Was too long to fit properly in the sump so changed to something else.

Had a 800w heater in there before but made a boo boo and melted the plastic cover. Draw was under 7 amps.


Sent from my iPhone using Tapatalk Pro
 
Don't. It will work fine for a while, then fail.
Possibly melting the plug or other internals.
But even worse, the relay could weld itself stuck on.

FYI:
800W / 120V = 6.6A
But, many heaters can draw quite a bit more for short periods when they turn on.
 
Vhuang168 said:
How big is the tank?

My 190g tank +60g sump is being heated by a 500w heater in an uninsulated garage.

c9e51cf3ea43b604bd80c0271e63c666.jpg


That heater draws a max of 3.8A.

It is a Finnex titanium heater.

The tank was actually being heater by a 300w Ehiem from Nov to mid Dec. Was too long to fit properly in the sump so changed to something else.

Had a 800w heater in there before but made a boo boo and melted the plastic cover. Draw was under 7 amps.


Sent from my iPhone using Tapatalk Pro
Click to expand...
The target is a 90g total volume garage tank, the 500W Aquatop heater wasn’t able to heat it above 74F. So I’m going to try two Ink Birds with two Finnex 500W titanium elements in an Apex. There is a lot of surface area and turbulence and evap cooling is probably contributing a lot.
 
Chromis said:
The target is a 90g total volume garage tank, the 500W Aquatop heater wasn’t able to heat it above 74F. So I’m going to try two Ink Birds with two Finnex 500W titanium elements in an Apex. There is a lot of surface area and turbulence and evap cooling is probably contributing a lot.
Click to expand...
I had to wrap my qt tanks in the garage with Styrofoam insulation to help keep Temps up during the winter. They were removable for when I needed to look at the fish.
 
Chromis said:
The target is a 90g total volume garage tank, the 500W Aquatop heater wasn’t able to heat it above 74F. So I’m going to try two Ink Birds with two Finnex 500W titanium elements in an Apex. There is a lot of surface area and turbulence and evap cooling is probably contributing a lot.
Click to expand...

That's like 1/3 of my volume. The heater might have been faulty. How many amps was it pulling?

As I mentioned, I had a 300w Eheim keep that take at 78 for months. Only picked up the 500w because of the mishap with the 800w.

Rhode Island huh! ;)
 
Chromis said:
The target is a 90g total volume garage tank, the 500W Aquatop heater wasn’t able to heat it above 74F. So I’m going to try two Ink Birds with two Finnex 500W titanium elements in an Apex. There is a lot of surface area and turbulence and evap cooling is probably contributing a lot.
Click to expand...
Is this a new tank for you? I don’t remember you having a 90g in your garage.
 
Vhuang168 said:
That's like 1/3 of my volume. The heater might have been faulty. How many amps was it pulling?

As I mentioned, I had a 300w Eheim keep that take at 78 for months. Only picked up the 500w because of the mishap with the 800w.

Rhode Island huh! ;)
Click to expand...
I don’t know what kind of amps anything is pulling because I haven’t set up the Apex yet. I have a 300W Aquatop in my 25g quarantine garage tank because a smaller heater couldn’t keep it stable all winter. There’s little heat build up from all the energy-efficient equipment and LEDs, I guess that will help in the summertime...
 
Ok so I rechecked my 25g garage QT and it is only running a 200W heater, an Aquatop that is probably the biggest one that can fit into the IM25. Just wanted to correct the record :)

Back to the 90g garage system, I have the 800W Finnex/Inkbird NOT plugged into the EB832 because it could potentially pull more than the EB832 7A rating and damage an outlet. So, I’m watching the tank temp profile over time via the Apex. Question is, how can you tell if a heater is the right size by the temp profile? Currently the heater “on” time (the time to raise the tank temp about 1deg-F) is about 2 hours. The time for the tank to cool down 1deg-F is 1 hour. Is there a rule of thumb ratio for heater on-time to off-time?
5d33e68f2b91774d65818f0f99aff54f.jpg
 
So doing some quick algebra on that graph...
You essentially have a -533W chiller connected to your tank.

So it seems what you really want, Assuming target temp = 76-77:
A 500W heater, that goes on below 77. So pretty much always on.
A 300W heater, that goes on at 76, off at 77.
That should make graph MUCH flatter, and oscillate between 76-77.
And reverse the heaters/temps in the summer.
 
I wouldn't worry too much, takes you 2 hours to go from about 76 to 77 degrees, a larger heater will do it quicker no doubt. but your graph looks a bit more worrisome than it really is because the zero point isn't located on it. I don't think there's a rule of thumb for the ratio between on to off. Longer off is, IMO, ideal just from the electrical side of things, but the size of the heater isn't going to affect how much time it takes for the temp to drop.
 
I would tighten the control points a bit, but I wouldn’t worry about on/off time unless it gets to be a very high percentage of on time. I’d only worry about that because it would imply you didn’t have enough heater, or were at least close to that point.
 
I had two 200w heaters and one was the primary that would turn on more frequently and the other only went on if the first one couldn’t keep up.
 
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