How to incorporate a minisplit into my room? (24k-36k)

[Zarezhu]

Hey guys, its getting close to the end of the outdoor season, and my mediocre outdoor this year is extremely subpar. I'm hoping to have my indoor room ready to flip early/mid November, so I'm trying to get the ball rolling right now, and hopefully have a nice grow journal for you guys towards the end of the year.

I had an electrician come out and put a subpanel in our 12 ' x 12 ' shed(100 feet from the home). Homes on a 100amp main, we tapped into an unused 50a 240v breaker and brought it out to the shed (8 gauge thhn wire 90degree C, I believe, is rated for up to 55 amps at 100 feet?). If necessary, I can buy a 55 amp breaker and replace the 50 amp, I'm not sure how necessary this will be.

The subpanel has a 50 amp 240v breaker on an intermatic timer, with 5 or 6 240v plugs. The sub panel also has a 20 amp 120v breaker, with a few plugs as well. Even though I have 70 amps of breakers, I can't pull more than 50 amps (or 40 amps continuous power?).

What I would LIKE to do, is run 5KW bloom with a 24k-36k btu minisplit. A harvest or two down the line, if things go well, I would like to upgrade the homes main panel, run another 50 amps to the sheds subpanel, and do a 8kw or 9kw sealed bloom room.

Is it possible for me to put a 24k or 36k btu ac safely on the same 50a breaker as the 5kw of lights? On the 120 circuit we'd only have a few oscillating fans, a pond fogger, and co2 gen.
-if it was on the same 240v breaker, the ac would be on the same 12 hour cycle as the HIDs.
-I'd really prefer to install a 36k btu, so I could chose to run bare bulbs, omitting the need for any inline fans and holes in walls that need to be blacked out, and allow me to upgrade to 8 lights as long as I exhausted my hoods at that point.

- 5 ballasts/bulbs @ 4.5 amps each = 22.5
- 36k btu ac, max amp draw is 17.8 amps
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40.3 amps, only 22.5 of which are continuous power
This would technically leave around ten amps for 120 v appliances, correct?
Seems reasonable to me, but am I missing something?

 

[Mr. Miyagi]

you're asking a lot by putting all of that on the same load... if something was to ever happen and that breaker tripped, you lose power to all of that...

I usually try to have fans and lights on separate circuits...

 

[jav2043]

You should install mini on its own dedicated line and breaker.

 

[the gnome]

 

[Zarezhu]

Could I split the 50a 240 in my subpanel into 2 30a 240's?


I didn't really know how important it was to have on its own breaker, considering its following the 80% continuous load rule and the ac isn't even really a continuous load.

I'm also fairly certain I can only run a 24k btu mini split. Which sucks, but I'll just have to aircool my lights.
http://www.sylvane.com/friedrich-breeze-br1224w3a-split-ac.html
This is the best unit I have come across so far. 18 seer I believe, and with quick connects, for under 2k shipped. Definitely need a unit with quick connects. This unit claims a max ac draw of something iike 1780 watts?




At this point, I'm also trying to figure out if my electrician was right about the wire sizing. We tapped into the homes 50A 240v unused circuit, and ran 120' of 10-4 THHN wiring to the subpanel in the shed. We used 2 runs of 10 gauge for the hots and 2 runs of 12 gauge for the ground and neutral. 10ga wire is rated for 30A, so does that mean it can do 60A if there's 2 leads? Or 55A? Or is my subpanel only able to pull 30A max?

 

[the gnome]

Could I split the 50a 240 in my subpanel into 2 30a 240's?


I didn't really know how important it was to have on its own breaker, considering its following the 80% continuous load rule and the ac isn't even really a continuous load.

I'm also fairly certain I can only run a 24k btu mini split. Which sucks, but I'll just have to aircool my lights.
http://www.sylvane.com/friedrich-breeze-br1224w3a-split-ac.html
This is the best unit I have come across so far. 18 seer I believe, and with quick connects, for under 2k shipped. Definitely need a unit with quick connects. This unit claims a max ac draw of something iike 1780 watts?

running HID lamps your AC will be running nonstop with 5000w of open bulbs, different story with aircooled and I haven't gone that route so can't say.

rives is the local in house AAA spark ace
hopefully he'll drop in in.

i have that same 24,000btu mini split
as a back up for my 32.5K btu mr slim
the quick connects are thee bee's knee's

 

[tenthirty]

Is it possible for me to put a 24k or 36k btu ac safely on the same 50a breaker as the 5kw of lights?
On the 120 circuit we'd only have a few oscillating fans, a pond fogger, and co2 gen.
-if it was on the same 240v breaker, the ac would be on the same 12 hour cycle as the HIDs.
-I'd really prefer to install a 36k btu, so I could chose to run bare bulbs, omitting the need for any inline fans and holes in walls that need to be blacked out, and allow me to upgrade to 8 lights as long as I exhausted my hoods at that point.

1) The 50a breaker should act as a feed to smaller breakers and split up your lights 2 to a receptacle/ breaker, and pumps fans ac head units on appropriately loaded receptacles and smaller breakers.
If it were me, I would build the light relays right into the panel or secondary panel.
It may be better to do another run from the house for the AC in order to minimize voltage droop or drop at startup also a 50a main for everything hits me as being just a little to small.

2) Please make up a list of all the electrical equipment that will be in the on state and calculate the load in amps. All the manufacturers sites publish this information.

3) Remember that you are also cooling the ambient heat load,
36k btu may not do 8 lights added to summertime temps.

4) IMHO in a 12X12 room, you could run 2 4x8 tables and still be able to work. That would create 64 sq ft of canopy.
4 DE Gavita's would get you better than 62.5 watts sq ft.

Looks to me like the room should be a 4 lighter. and at that level with a well insulated room you should be able to keep up with 36k btu.

Now if it were me, I would put 2 16k btu systems in to save money and create some redundancy,
considering the value of 1 lost crop at that size, not to mention all the lost time and consumables.
I would also run it as a monthly perpetual to break up the work.


--2 pence ;-)

 

[jav2043]

I went with Friedrich Breeze and what a breeze to install and super quiet as well. All you need is a dedicated 240 15amp breaker on your panel for it.

 

[amannamedtruth]

Yr gonna want to run 100 amps out there.

 

[Zarezhu]

@jav - The 24k btu only requires a 15 amp breaker? Or did you get one of the smaller Breeze units? Also. do you run yours at night? Looking up the specs, its meant to run at a minimum of 60 degree F temperature, and winter nighttime temps here can dip into the high 30's (NorCal). Would the friedrich wind baffle/low ambient kit keep me from freezing over in the dead of winter(Rarely hits low 40's even, but possible)?

@amannamedtruth - I definitely want to run 100 amps out there. I even ran 1.5" conduit to the shed, so when I upgrade the homes main panel, I can use the same conduit and just pull more wire through it, super easy. Only problem now is money, I don't have the funds to upgrade the homes 100A main panel. A few harvests down the line I will, and I will redo much of the room.

@tenthirty -

I may be able to run a 10ga extension cord from the house for an additional 15a 120v, but the main panel has no more room for me to draw any additional 240v power without upgrading the panel (will be done after 1/2 harvests).

The following has yet to be purchased, so these are all guesstimations ,but it's all I have to work with:

4 oscillating fans, 120v @ 1A each running 24/7 (4A total)
1 Humidifier, 120v @ 1.5A also running 24/7
1 Co2 controller, 120v, ??A (not sure which controller, or if the controller even uses any significant power)
1 Co2 Gen(LP), 120v, 1.5A
1 24kBTU friedrich breeze minisplit, 240v @ ~8A (seems really low, but 240v with 1800 watt draw equates to roughly 8A).
I figure with my ac running 80% of the time, I won't need a dehuey just yet. Once the plants are a few weeks into bloom, I'll just shut the humidifier down and let the humidity drop via the ac.
-------------------------------------------------------------------------
I purchased 4 1000w digital/dimmable quantum ballasts, along with 4 Magnum XXXL hoods ($600 +1oz, thx craigslist)
If I stick to the quantums, they're just under 4.5A per, so 18A for 4kw
I'm extremely interested in the Gavita 1000's. I just MAY be able to scrap my quantums and go straight to 4kw of Gavitas, as long as my 24k btu ac can handle it?
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If I have the extra amperage, I would love to be able to bloom 5kw until I can upgrade the panel and bloom 8kw Gavitas with a 4-5ton AC. My original plan was to aircool the 4 Magnum XXXLs, running 1000w HPS each, and to run a fifth 1000W MH bare bulb/adjustawing on a light mover, running between the two tables. This would require an exhaust fan for the 4 XXXL's, but the BTU heat load should be similar to 4kw of Gavitas.

Edit: I don't mind filling the room up completely, and having very little space to work. My plants will all be sized properly to fully bloom in 8 weeks with no pruning necessary, and watering is simple as well. I plan on running this shed perpetual to another shed, meaning this shed runs Nov, my second shed (slightly larger) will start its run Dec. I don't consider a 4kw grow to be too much work, even 8kw. I've quit my day job and have all the time I need to dedicate to my babies.

What about installing a 36k btu ac (18 amp draw max), running 5kw (4 magnum xxxls without the glass, and 1 adjustawing MH fixture (22.5A), making it a total draw of 40.5A on the 50A 240v breaker. I then run a 10ga Heavy Duty Outdoor Extension cord from the homes 15A 120v circuit, and put all the 120v appliances on the homes circuit (seems like its 9-10A MAX). All my load draws would be less than 80%, and I would have an AC that could cool 5kw bare bulb easily (6k btu barebulb x 5 bulbs = 30k btu heat from bulbs, leaving 6k btu extra cooling)

Does anybody know of any 36k btu mini's that come with precharged linesets? I'm having a hard time locating one.
Just found this one : http://www.heatandcool.com/INVERTER...source=shopping&utm_medium=comparisonshopping
32k btu with precharged linesets, fairly cheap as well. It is pretty low SEER though (14).

 

[the gnome]

Now if it were me, I would put 2 16k btu systems in to save money and create some redundancy,
considering the value of 1 lost crop at that size, not to mention all the lost time and consumables.
I would also run it as a monthly perpetual to break up the work.


--2 pence ;-)

this is why i added the 24K btu breeze to my 32,500btu mr slim.
back up, 6 lamps and your pulling down 10-12+ bows every 60 days
what happens if your ac takes a dump--->5wks in bloom---> in summer...
and you can't have Hvac fugging around your grow or the parts to fix it are gonna take 2-3weeks to get
FUGGG ME


the $1800 i paid for the breeze is verrry cheap insurance.
also my 14x20ft room with the ac at one end leaves the far side warmer by 5-7 degrees.
2 mini's really minimize any hotspots and my ac bill actually went Down from the efficiency with 2 units

 

[Zarezhu]

Yeah that is a great point. Now that I really thing about it, I'd add a second 24k btu after my first harvest, along with upgrading the panel, adding an additional 50A, and additional lights. This would put me into the 4-5 ton cooling range, letting me run 8 gravitas no problem.

 

[Wendull C.]

You should ask your electrician where he came up with a ten gauge wire carrying a 50 amp load at 100'. That needs a 6 gauge feed no matter how many hots you have.
Not including voltage drop.

 

[Zarezhu]

Blah, that's what I feared. The electrician is actually a friend of the home owner, I'm just renting from the home owner. The home is pretty old, lot of its real beat up. Maybe he wants us to burn the house down?

 

[Zarezhu]

My bad guys, I just checked the wire and its 8ga thhn. Does that mean I can safely run 45A or 50A at 100 feet? There's s actually about 115-120 feet of wire from main panel to sub panel.

The wire we have is rated for 90 degrees C, which with a quick google search,shows is supposed to be able to handle 55A (50A for 75C, 40A for 60C). Since my lights and ac will pretty much be continuous power, I can only use 80% of the breaker, leaving me with 44 available amps. Is this correct?

 

[Wendull C.]

It is correct that you should leave 20% for start load on your lights.
I have always thought and been taught more is better when dealing w electricity.
In commercial electric many moons ago 10 wire was a 30 amp circuit 8 wire a 40 amp circuit and 6 wire a 50 amp circuit.
You may be able to stretch that a bit if you live in a colder climate as wire can Carry more load at a lower temp.
At 120' I would not push it.
The way a breaker stops wire from combusting is tripping when too many amps are pulled for the rated wire. By placing a 50 or 55 amp breaker on 8 wire you are asking for trouble.

If you try it touch the wires in the box and check them for heat at the very least.
Happy gardening bro. Wendull C.

 

[jav2043]

@jav - The 24k btu only requires a 15 amp breaker? Or did you get one of the smaller Breeze units? Also. do you run yours at night? Looking up the specs, its meant to run at a minimum of 60 degree F temperature, and winter nighttime temps here can dip into the high 30's (NorCal). Would the friedrich wind baffle/low ambient kit keep me from freezing over in the dead of winter(Rarely hits low 40's even, but possible)?[/B]

Yes I have the 24K btu hooked up to a 240 volt 15 amp breaker. I do run my lights to help with summer heat outside on the east coast. Even though my room is sealed I use outside air to cool my hoods. For security reasons my outdoor unit sits indoors in another room exhausting heat out through a window. Just built my room 2 months ago and so far running smoothly. Will see what happens when winter months arrive.