Help me Install 3 EG4 Mini Split Solar Heat Pumps

[MrM1]

@SpongeboB Sinewave
So I like the idea of the MN solar surge protectors, but my DC strings are 338v with a VOC of 372.

So I assume the 300v surge protector would not be enough, but I'm concerned that the 600v units will let too much surge voltage through, damaging equipment before going to ground with it.

Which one do I chose?

 

[Plum Crazy Rob]

I'm wondering ..

I'm seeing in the app (in the controls drawer) that there is a setting for AC Limiter.
- I don't have AC connected yet
- has anyone one tried this?
- what does it do?
- how much does it limit AC input power
- for does it's mean Air Conditioner limiter

View attachment 148628

Sure, that's what I griped about NOT being able to set Default - Always ON. (Default is OFF). On a 24k, it limits AC grid assist to 600W. (300W on a 12k I believe)

Scenario: Typical Winter cloudy day it was common to operate 300W Solar + 300W Grid for 600W (coincidental total, has NOTHING to do with 600W AC limit...) which made a nice little amount of heat. When the unit came on by scheduled time in Winter when there would be some Solar, say 9 or 10AM I would find the thing using 2000W of grid assist until you hit the Limit button!!

Has no function with no Grid as you've noticed.

 

[SilverbackMP]

@SpongeboB Sinewave
So I like the idea of the MN solar surge protectors, but my DC strings are 338v with a VOC of 372.

So I assume the 300v surge protector would not be enough, but I'm concerned that the 600v units will let too much surge voltage through, damaging equipment before going to ground with it.

Which one do I chose?

I’m thinking the 600v would be ok. It’s one of the fastest fuses you can buy and a near lightening strike is going to trigger them either way at about the same speed. I use 600v as my panels will produce around 570v on the coldest day of record at full sun. I have twelve panels in single serial strings going into two of three of the inputs on each of the top row of Sunny Boys. My panels are a bit of hike away so I went with higher voltage DC.

 

[SpongeboB Sinewave]

An SPD 600 would be fine for ~400V. Remember that a lightning arrestor SPD does not limit PV plus to minus voltage. (differential mode)

The are connected up in order to protect the inverter's or controller's insulation between those +/- wires and ground. i.e. The unit's chassis or case ground.

Since lightning tends to raise the voltage of both +/- lines together, (vs. GND), that's called common mode. So you have a MOV or varistor from each, plus and minus common connected to ground. So, 3 wires.

The unit you are trying to protect, even a refrigerator or toaster has a "hi-pot" test where they apply, possibly 1500 to 2000+ volts between chassis or unit's ground connection and the PV +/- wires tied together. It cannot arc across that insulation or else it fails at the factory.

An SPD 300 would be more suited for the AC grid drop lines and ground. They turn on (conduct) around the 450 V range as I remember.
Again, 3 wires. L1 and Neutral to ground.

The SPD 600 is something like 850 V IIRC. Suitable for most solar, wind, hydro etc. 600V(ish) max rated input devices.

boB

 

[MrM1]

With surge protectors I keep reading, "mount them closer to the equipment being protected".

So in my case, as close to the AC units as possible and not 50 ft up line where the PV comes in to the attic? Or does it not matter as much in a 50 ft run.

 

[MrM1]

Sure, that's what I griped about NOT being able to set Default - Always ON. (Default is OFF). On a 24k, it limits AC grid assist to 600W. (300W on a 12k I believe)

Well that's a shame it defaults to always off ~ actually kinda silly being the selling point is priority solar. Does ECO mode do anything?

Scenario: Typical Winter cloudy day... When the unit came on by scheduled time in Winter when there would be some Solar, say 9 or 10AM I would find the thing using 2000W of grid assist until you hit the Limit button!!

Scheduled time? Is there a scheduler in the app or a way to schedule or have the unit only operate certain times of day ? Or do you mean simply when it got enough solar power power to turn on ?

Are you on grid and solar all the time or are you manually turning the grid breaker off? Seems if you were powered on all the time (either by solar or grid), the Limit would stay ON. Does Limit reset itself every 24 hrs or something?

I'm considered wiring my AC power side with contactors with 120v control. Then plugging the control into a TP Link Kasa power strip so I can set timers on the AC power.

 

[Nobodybusiness]

Going from 85 outside to 75 inside not much load on it??

Also I'm sure this is relevant for Florida, if in DC only Solar mode, it will come on and search for adequate power for an hour or so - then if it's deep overcast or rainy it gives up / times out and display flashes LP (Low Power). If the sun comes out after this, you do have to cycle power to get it back ON.

That really stinks.

Why wouldn’t it check the PV to see if adequate voltage after initial check without a reset?

I guess on constant sunny days it won’t matter but still..

 

[Nobodybusiness]

down to 67

Man you guys keep it cold in your houses.

Even in dead of summer house never gets below 73.
Of course there is very little humidity in the house either.

 

[Plum Crazy Rob]

Great news. I might be WRONG about the LP -won't restart. Walked by it at 7:52 pm yesterday evening and indoor fan shutoff and LP started flashing. Keep in mind mine's in another room where I don't sit and watch it every second. So this implies it *IS* restarting after the LP the next AM. I thought it didn't because we had a deep overcast that shut it off one day, then sun came out. I walked by I thought it had been quite awhile was still flashing LP so manually restarted it.

Everybody let me know what your observations are on yours??

Yes the "Cloud Schedule" is where you add scheduled times of operation. Of course if you schedule at night with grid off nothing happens (lol) ?

 

[Plum Crazy Rob]

Here is my schedule from Winter when there were of course more dark dingy days which together with low sun angle / Solar I liked to have the Grid ON / available to assist. Run all day on or mostly on Solar, then come on GRID just before bedtime to Heat a little ? for overnight.

 

[SolarScott]

Man you guys keep it cold in your houses.

Even in dead of summer house never gets below 73.
Of course there is very little humidity in the house either.

I have always had to watch my budget and usually keep it around 76 to be able to afford to pay the electric bill......not anymore!. I get that puppy down as cold as my wife will let me so that by the evening when sun is gone I can turn it off and let it slowly warm up, all for free!

 

[MrM1]

Everybody let me know what your observations are on yours??

Yes the "Cloud Schedule" is where you add scheduled times of operation. Of course if you schedule at night with grid off nothing happens (lol) ?

Mines been restarting every morning after low power the night before. But I "Think" it did fully shut down due to low power yesterday during a passing rain shower. I did turn it back on ... but who knows ... if I had waited it may have restarted.

Great to know about "Cloud Schedule". But I am assuming if I lost internet, I'd lose the schedule too? Or does it send the schedule to the unit from the cloud? I seem to recall, with TP Link Smart Home Devices, they will work without internet on local area (LAN) only. So I might still install the AC power side contactors so I can control it and when I have AC power to the units on demand.

I already have 2 contactors set up on 120v control like that, one for in Schneider SW inverter to control grid input. That way if I am away from home and the batteries get low, I can just turn on grid support to the inverter and the batteries will only go down to a set voltage before grid kicks in. Also have one on my water heater. I heat my water with solar, but if not enough sun, I can flip it to grid for an hour for a quick warm up.

Here is a sample of what I have in smart home devices. Between Smart Bulbs, Smart Receptacles, Smart Power Strips and Smart plugs, I have 57 IP addresses total ?

 

[MrM1]

Speaking of Low Power, Mine woke up on the Test panels this morning at 8:10am (fan only), and here now in FL on a totally overcast day, it is producing 537 watts and cooling at 9:15am. Nice.

Well, off to finish a cup of coffee, then outside to finish the install of the 2nd 24k. Got both the head and condenser set, but no linesets or drain yet. I'll probably drag the test array around the house tomorrow to test unit number 2.

So far so good

 

[MrM1]

I just told my wife I am not sleeping well at night and that I think it is because the neighbor just installed a new "Solar Flare" LED light on the pole about 10 days ago. Totally lights up my bedroom.

She says, "No ... you're not sleeping because you're too exited and thinking about this install".

But I said no, but once I'm awake, that's why I can't go back to sleep. I mean, doesn't everybody wake up thinking about Bi-Directional DC Breakers? (that's what I was researching at 4am this morning) ?

 

[Plum Crazy Rob]

Lol. I'm in on the Yo-Link constellation of devices (wired in leak sensors to kick off a relay to my well pump if pipe bursts while im not home. Well pump has to be on because my main HVAC is Geothermal / water source). This is one of the reasons i got interested in backup HVAC and these Solar units in particular:

 

[MrM1]

12 ft thru an attic across a ceiling, and then a 90* bend down into an eve/ sofet ... whew ... its been a brutal day. I finally got all the lines outside and am about to start flaring and connecting to the 2nd, 24k.

The Lineset was about 1 ft too short (why is the 12K line set so much longer than the 24k lineset ). so I plan to use couplers to bring down that last few feet. I robbed about 3 feet off the 1st 24k because it there was so much extra, so it all works out OK

 

[MrM1]

Okay I'm back to pressure testing, I have the 24K at 525 psi. It has been sitting there for 2 hours. But it probably has dropped or settled about 5 psi or less in 2 hours. I did remove the yellow line and the nitrogen tank. I have the blue line low side valve closed and it's just sitting there holding pressure except that slight little drop.

It's moved from the backside of that E, to just wear the three prongs of the E are in 2 hrs. Or, lets say its moved about 1/2 the width of the needle in 2 hours. Was that because I removed the Nitrogen, or would you say I have a leak in one of the coupling/flares? Or nothing to be concerned about.

 

[timselectric]

If it doesn't continue to move. You're fine.

 

[FilterGuy]

If it doesn't continue to move. You're fine.

It hasn't moved since I looked at the picture 20 minutes ago!

 

[MrM1]

It hasn't moved since I looked at the picture 20 minutes ago!

Now that is funny.