EG4 Heat Pumps?

[Plum Crazy Rob]

Dipping toes in Solar....got mine installed (DIY if not obvious..)

In my case, had to bring 220V from power pole due to no free space in house sub panel (future upgrade project)

Panels are Canadian 385W, note only 7 hooked up at the moment due to Voc concerns. DC breaker at panels, I have since corrected the backwards wiring on it. Chinese IMO DC disconnect on house. I'm so committed racks are on 5 gallon buckets of concrete buried (sarcasm).

It does what it was said to do. Heating 1000sq ft no problemo! Very happy so far!!! Had first partly cloudy day yesterday, AC fills the DC valleys to keep wild power swings at bay as some were wondering. Wichita KS current Solar hours 10AM - 4:30PM.

This is all Sig Solar too, very happy with them as well. Made an order change, they called me right back no prob.

More thoughts later.

 

[Plum Crazy Rob]

Oh, indoor unit pic:

 

[AJB]

I'm so committed racks are on 5 gallon buckets of concrete buried (sarcasm).

I resemble that remark, though my buckets are bottomless over a bit of rebar set as an inverted shroom cap.
Now when I skip town to escape the crazy heat of SW AZ I won’t return to wax puddles where candles once lived. I ordered this 24k unit from AU last spring, I’m about to order 4 more.

Whomever was asking about 48v units, they have been around for years.

And to think I relocated here from ICT in 2020. Rob I’d say that’s opportunity missed, but i’m sure glad I wasn’t there the last couple of months! I definitely prefer endless blue sky’s!
Actually we should have a chat sometime.
~AJ from AZ

 

[Plum Crazy Rob]

Hello AJ. You come from the Aircraft biz by chance? (ex Structures Design Engineer here). THAT is an amusing coincidence on the buckets, great minds. I have trees on 4 sides so probably knock 50mph off any high winds.

You or anyone speak Chinglish for these Deye units?? From the Deye app...Light=Display on-off, got that. What does ECO mode do..seems air conditioning related as it switches unit to cooling mode. ANION. What the he11 is that. Interestingly, the manual that arrived with my unit seems to be written by an Australian feller as it makes numerous references to AU-NZ code, as well as the lilt and spelling differences. Cloud Schedule - I would schedule no clouds but obv refers to schedule of operation got that set up.

 

[Rocksnsalt]

I get lost on acronyms.
I get AU and NZ.

 

[ksJoe]

What am I missing here, this unit seems like a bad choice if a person is looking for optimal electrical efficiency?

I'm looking at building an off-grid cabin and will be using solar for power and a split unit for heating/cooling. I'm approaching this as: should I take some panels off the main system and connect them to this split unit. I think the answer is no.

The minimum DC voltage is 90, so it must be direct connected to solar panels. Any time I'm not needing heating/cooling, those panels would be unused. So when I need heating/cooling, it would be more efficient. But when its not running, I have a 100% loss on the panels connected to the split unit, right? I suspect I'm better off to connect all the solar panels to the charge controller and batteries so I can use all their power the entire time sunlight is available (just losing some conversion when the split unit needs to run).

If this unit would run on 48vdc, so I could connect it direct to the batteries, this would be an extremely appealing choice. In that case all my solar panels can be devoted to a single solar system and the split unt would draw DC from the batteries for efficiency.

This unit seems great for scenarios like:
- you have no solar and would like a split unit to be solar powered without the cost batteries, charge controller, etc.
- your solar system is underpowered and you can't cost effectively add panels without upgrading a lot of infrastructure.

It just doesn't seem worthwhile for other scenarios.

 

[timselectric]

What am I missing here, this unit seems like a bad choice if a person is looking for optimal electrical efficiency?

I'm looking at building an off-grid cabin and will be using solar for power and a split unit for heating/cooling. I'm approaching this as: should I take some panels off the main system and connect them to this split unit. I think the answer is no.

The minimum DC voltage is 90, so it must be direct connected to solar panels. Any time I'm not needing heating/cooling, those panels would be unused. So when I need heating/cooling, it would be more efficient. But when its not running, I have a 100% loss on the panels connected to the split unit, right? I suspect I'm better off to connect all the solar panels to the charge controller and batteries so I can use all their power the entire time sunlight is available (just losing some conversion when the split unit needs to run).

If this unit would run on 48vdc, so I could connect it direct to the batteries, this would be an extremely appealing choice. In that case all my solar panels can be devoted to a single solar system and the split unt would draw DC from the batteries for efficiency.

This unit seems great for scenarios like:
- you have no solar and would like a split unit to be solar powered without the cost batteries, charge controller, etc.
- your solar system is underpowered and you can't cost effectively add panels without upgrading a lot of infrastructure.

It just doesn't seem worthwhile for other scenarios.

That's why I have chosen a 48v mini split.

 

[Rocksnsalt]

That's why I have chosen a 48v mini split.

have a link to it?

 

[timselectric]

have a link to it?

Solar & DC Air Conditioners | 48v DC Solar & Telecom Air Conditioner Heat Pump | Off-Grid Air Conditioning

 

[Rocksnsalt]

What am I missing here, this unit seems like a bad choice if a person is looking for optimal electrical efficiency?

I'm looking at building an off-grid cabin and will be using solar for power and a split unit for heating/cooling. I'm approaching this as: should I take some panels off the main system and connect them to this split unit. I think the answer is no.

The minimum DC voltage is 90, so it must be direct connected to solar panels. Any time I'm not needing heating/cooling, those panels would be unused. So when I need heating/cooling, it would be more efficient. But when its not running, I have a 100% loss on the panels connected to the split unit, right? I suspect I'm better off to connect all the solar panels to the charge controller and batteries so I can use all their power the entire time sunlight is available (just losing some conversion when the split unit needs to run).

If this unit would run on 48vdc, so I could connect it direct to the batteries, this would be an extremely appealing choice. In that case all my solar panels can be devoted to a single solar system and the split unt would draw DC from the batteries for efficiency.

This unit seems great for scenarios like:
- you have no solar and would like a split unit to be solar powered without the cost batteries, charge controller, etc.
- your solar system is underpowered and you can't cost effectively add panels without upgrading a lot of infrastructure.

It just doesn't seem worthwhile for other scenarios.

Well, that all makes sense for your use case, it’s certainly one of a few ways to go.
For some that may be connected to the grid, it seems appealing to cool or heat directly from solar panels for a significant number of days, keeping the building at or near desired temperature and have the system be able to run from grid power if needed after solar hrs, nights, and/ or cloudy days. In my case I’m thinking this may work well as summers get quite warm at times, and it gets a bit cold in winter, but often sunny.
At some point I plan to have batteries and inverter at this place but likely nothing substantial for a couple years.

Re loss of energy from the panels not feeding the rest of a system when not needed for ac or heat, couldn’t that be switched and wired to tie in with the rest of a system?

 

[Rocksnsalt]

Solar & DC Air Conditioners | 48v DC Solar & Telecom Air Conditioner Heat Pump | Off-Grid Air Conditioning

Thanks

$2095 for 12k btu?
plus shipping etc?

 

[Plum Crazy Rob]

Still happy with what I needed mine for, principally backup and offset HVAC cost - which is 50-65% of my electric use in the first place. Saving about $80-100 a month at $ 0.14 / kwh so far. Only April and October are shoulder season months in KS where you dont need much HVAC.

I am mystified why Sig Solar doesn't sell the 48V Deye unit...this topic discusses but doesn't really answer the question. Seems like there is demand for it? For the record, they do make a 2 ton hybrid ducted unit as well....

Why hybrid solar air conditioners but not the 48vdc ones?

Anyone have any idea why Signature Solar sells the hybrid "solar" air conditioners (which directly connect panels via MC4 connectors) rather than the straight 48vdc ones? They sell this one https://signaturesolar.com/eg4-hybrid-ac-dc-solar-air-conditioner-1-ton/ but it uses grid power when the...

diysolarforum.com

 

[Rocksnsalt]

Still happy with what I needed mine for, principally backup and offset HVAC cost - which is 50-65% of my electric use in the first place. Saving about $80-100 a month at $ 0.14 / kwh so far. Only March and October are shoulder season months in KS where you dont need much HVAC.

I am mystified why Sig Solar doesn't sell the 48V Deye unit...this topic discusses but doesn't really answer the question. Seems like there is demand for it? For the record, they do make a 2 ton hybrid ducted unit as well....

Why hybrid solar air conditioners but not the 48vdc ones?

Anyone have any idea why Signature Solar sells the hybrid "solar" air conditioners (which directly connect panels via MC4 connectors) rather than the straight 48vdc ones? They sell this one https://signaturesolar.com/eg4-hybrid-ac-dc-solar-air-conditioner-1-ton/ but it uses grid power when the...

diysolarforum.com

Agreed re SS not selling 48v heat pumps. Seems like they have a disconnect there since they sell a lot of 48v stuff.
I’m also mystified WHY the EG4 mini splits are not sealed quick connects to make them truly diy friendly.
My rant about that is in an earlier post #18.

And I’m with you re “shoulder seasons”.
Though I really don’t like blower type systems, they’re seemingly the most efficient and economical at heating or cooling for an older home.

 

[Vigo]

This unit seems great for scenarios like:
- you have no solar and would like a split unit to be solar powered without the cost batteries, charge controller, etc.

Even then, you're still paying for the controller, it's just rolled into the unit cost and the controller can't be used for anything else. Agree with the rest of your points.

Agreed re SS not selling 48v heat pumps. Seems like they have a disconnect there since they sell a lot of 48v stuff.

One downside of powering something with 48v directly is now you either have to locate your outside unit very near to your 48v pack, or you have to pay for 48v-size cabling at whatever distance, and either pay to prevent, or just live with, the voltage drop on that run of wire. It may be a benefit in some cases but in other cases it might be 50+ft of wire even if its only a 20ft distance point to point. Wire that needs to be sized for let's say 1500-2000w for a 12kbtu unit (assuming max draw + fudge factor) so maybe 40amps max.. it ends up being a fairly expensive run of wire compared to 1500w of 120vac wiring or 1500w of 150+vdc PV wiring. Just a factor to consider, anyway.

 

[Rocksnsalt]

Even then, you're still paying for the controller, it's just rolled into the unit cost and the controller can't be used for anything else. Agree with the rest of your points.


One downside of powering something with 48v directly is now you either have to locate your outside unit very near to your 48v pack, or you have to pay for 48v-size cabling at whatever distance, and either pay to prevent, or just live with, the voltage drop on that run of wire. It may be a benefit in some cases but in other cases it might be 50+ft of wire even if its only a 20ft distance point to point. Wire that needs to be sized for let's say 1500-2000w for a 12kbtu unit (assuming max draw + fudge factor) so maybe 40amps max.. it ends up being a fairly expensive run of wire compared to 1500w of 120vac wiring or 1500w of 150+vdc PV wiring. Just a factor to consider, anyway.

Re
“Even then, you're still paying for the controller, it's just rolled into the unit cost and the controller can't be used for anything else.”

I know it’s not the cool electrical nerd / mad scientist way to look at things but to me sometimes simplicity and having something relatively self-contained / plug ‘n play is a desirable future. Which is another reason I think SS is totally blowing it by not having these hybrid systems set up for easy diy- pre-charged quick connects.
That’s what I’m looking for.

What I’m really curious about though is how reliable and long lasting are these units going to be.

 

[Vigo]

Reasonable position to take! There's no real downside to the end user of having a precharged line set since the added cost is far less than paying a contractor to do any of it, from what i've seen.

Although, if there is room to add more one thing to the package and just roll it into the price.. one might consider a torque wrench for the line fittings. No point having refrigerant that's here today gone tomorrow.

 

[timselectric]

Even then, you're still paying for the controller, it's just rolled into the unit cost and the controller can't be used for anything else. Agree with the rest of your points.


One downside of powering something with 48v directly is now you either have to locate your outside unit very near to your 48v pack, or you have to pay for 48v-size cabling at whatever distance, and either pay to prevent, or just live with, the voltage drop on that run of wire. It may be a benefit in some cases but in other cases it might be 50+ft of wire even if its only a 20ft distance point to point. Wire that needs to be sized for let's say 1500-2000w for a 12kbtu unit (assuming max draw + fudge factor) so maybe 40amps max.. it ends up being a fairly expensive run of wire compared to 1500w of 120vac wiring or 1500w of 150+vdc PV wiring. Just a factor to consider, anyway.

21a at 48v.
#10 for up to 25ft
#8 for up to 45ft
#6 for up to 70ft
#4 for up to 100ft
Yup, closer is always better.

 

[Vigo]

I would say it's actually worse than that unless you're just ok with some wire heating and voltage drop. Im assuming a 12k btu unit as well, which will probably pull around 1500w in worst-case scenario conditions. Now, are those the conditions you need to size wire for? Depends on legalities and personal opinions, i guess.

But i feel like people are overly optimistic about the MAX amp draw of mini splits being low, when it's really the average that is low. Generically speaking a mini split has to do extra energy conversion to run its most power-hungry component (the compressor) vs a non-inverter-driven compressor. They do tend to run more efficient fan designs on the indoor unit at least but if you actually try to get 12kbtu/hr out of a 12k unit (which sort of requires worst case conditions since it will probably only do that at high ambient temps) you're probably losing more doing extra conversions before powering the compressor and condenser fan at full power, than what you're saving with a more efficient interior fan. There are other factors like size of the heat exchangers but my overall assumption is that a mini split will have similar or slightly worse draw than a non-inverter AC of same btu at max power & worst conditions, with the main difference being that unlike the non-inverter AC it will actually throttle far down from that rather than dropping to perhaps 70-80% of max and then cycling on/off. Also, no inrush which is nice.

Just as a data point i have seen my inverter-driven 8k btu Midea which functions like a mini split and at least last year was the highest SEER window unit, hit 1000w. If i designed a circuit for a 12k around a 1000w number, it would be with the extenuating justification that it wasn't likely to stay over 1000w for very long. But i would fully expect it to hit 1200+ watts under worst case conditions, at least here. Not everyone lives in South Texas, though!!

 

[timselectric]

I got the 21a from the spec sheet.
My run is less than 20ft. But it's #8 because that's what I do. I prefer all of my conductors to remain at room temperature.

 

[cmcdhuibh]

This thread has been going for some time with the the question about why the line set isn’t precharged. Typically the condenser is pre charged for a specified length of line. So the line set just has a nitrogen charge in it to keep it moisture free. I guess this is the argument. You want to be able to cut or add to the line set to what you need or have a messy excessive coil. DIY’ers can’t buy Freon for a good reason. A vacuum pump is cheep, and needed to work with AC. You will need to evacuate the line before you open the valve. If you don’t, there will be air/moisture in the line. Most units require a filter to be silver soldered to the line set so you also need to use a small amount of nitrogen to keep the inside of the pipe clean. The capillary tubes in the coil are very very small and the filter won’t always clean the burnt scale out.

 

[42OhmsPA]

I'm pulling the trigger on a 12k unit in the next month, I'm currently set on the Pioneer with free shipping. https://www.pioneerminisplit.com/pr...ull-set-with-16-ft-kit?variant=40106898063402

Is there any reason why I should go with the EG4 / Deye if I already have a split phase inverter fed by 5.8kw PV / 22kwh batteries? Will it qualify for rebates / tax credits?

 

[Rocksnsalt]

This thread has been going for some time with the the question about why the line set isn’t precharged. Typically the condenser is pre charged for a specified length of line. So the line set just has a nitrogen charge in it to keep it moisture free. I guess this is the argument. You want to be able to cut or add to the line set to what you need or have a messy excessive coil. DIY’ers can’t buy Freon for a good reason. A vacuum pump is cheep, and needed to work with AC. You will need to evacuate the line before you open the valve. If you don’t, there will be air/moisture in the line. Most units require a filter to be silver soldered to the line set so you also need to use a small amount of nitrogen to keep the inside of the pipe clean. The capillary tubes in the coil are very very small and the filter won’t always clean the burnt scale out.

I get that. But does everyone want to buy a vac pump - yet another tool cluttering the place- to use once? Not me.
If you’re not in or near an urban area it can be challenging and likely expensive to get an AC tech to drive to you, driving overall cost and payback period up. And talk to any tradesman or service company about coming to finish a diy job. Not going to find many that are interested, because prior experiences have turned out to be pita’s.
Simple solution is offer a few different length options for precharged lines.
8ft, 12ft, 16ft, 20ft.

 

[Rocksnsalt]

I'm pulling the trigger on a 12k unit in the next month, I'm currently set on the Pioneer with free shipping. https://www.pioneerminisplit.com/pr...ull-set-with-16-ft-kit?variant=40106898063402

Is there any reason why I should go with the EG4 / Deye if I already have a split phase inverter fed by 5.8kw PV / 22kwh batteries? Will it qualify for rebates / tax credits?

What’s drawing you to the Pioneer?
Totally understand just using a normal 120 or 220v unit if you have a system with plenty of power to run it and don’t mind the inverter loss.
I’ve looked at the Mr Cool 4th generation units Costco sells.
But there’s 120 and 220v 12kbtu units on amazon for $799.
My idea is that I would dedicate 1200w in panels (3 400w) for a 12kbtu mini split and maybe have it switched to just feed the system when I end up with a legit bigger system with batteries etc.

 

[42OhmsPA]

What’s drawing you to the Pioneer?

I've read way more good about them than bad, - 13F low ambient for the unit I linked and, they appear to have been around for long enough that reliability isn't a concern. It's my understanding they are manufactured by midea.
Is there another brand I should consider?
I was also looking at senville and daikin, I've ruled them out for specific reasons I can't remember.

Totally understand just using a normal 120 or 220v unit if you have a system with plenty of power to run it and don’t mind the inverter loss.
I’ve looked at the Mr Cool 4th generation units Costco sells.
But there’s 120 and 220v 12kbtu units on amazon for $799.
My idea is that I would dedicate 1200w in panels (3 400w) for a 12kbtu mini split and maybe have it switched to just feed the system when I end up with a legit bigger system with batteries etc.

I've looked at the Mr Cool on and off, I just can't justify the extra money for the quick connects when I can buy a vac pump and gauges at a cheaper cost while also having more tools I'll rarely use ?

 

[Danke]

DIY’ers can’t buy Freon for a good reason.

Kinda sorta…