Decision on Inverter

TKB4

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Critical loads panel and load-shed relay is for when on battery and SoC gets low.
I only have Sunny Boys on critical loads panel - the entire house would be load-shed at 70% DoD, but Sunny Island remains up down to 80% DoD so when the sun comes up Sunny Boys see AC and start delivering power.
Eventually I'll shed less important loads like laundry and outdoor lights at 20% DoD. I plan to wire things as (on-grid) OR (> 80% SoC).
You may want separate critical loads rather than running the generator at night. If your PV is AC coupled (Sunny Boy) rather than DC coupled then you should separate them.

I have net metering so Sunny Boys backfeed the grid.
DC coupled PV doesn't backfeed the grid with Sunny Island unless SCC are set to a higher voltage than SI.

I'm not sure how well Sunny Island supports zero-export. So long as PV is less than battery charging plus consumption, you would be a net consumer. I think SI would also suck down power from the grid to recharge batteries faster. Once battery charge current tapers off and you have surplus PV, to prevent export it can disconnect from grid; it would then raise frequency to curtail production.

What you might like is to remain grid connected with batteries floating and PV curtailed to match load. SI can't do that because it uses frequency shift. Possibly Sunny Boy Storage (400V lithium battery) could, because it has a data link to newer model Sunny Boy. But it is featured as working with all GT inverters; for most of those it would have to cycle batteries while leaving the GT inverter on at full output or knocked off line for zero output. Note that Sunny Boy Storage is a wimp, can't power as much or offer the surge capability of Sunny Island.

But compared to Sunny Island plus generator, obviously Sunny Island plus grid is going to be cheaper and less maintenance.
I dont want to run generator at all and definitely not at night unless grid down HOA with at least 5 acre lots. I will not sell to grid . I need grid for power when solar/battery not enough power. I plan to add more battery in steps to eventually 100kwhr or so. I do not and will not have Net Metering. I also do not want to charge batteries with grid at all. If grid down and not enough PV will use generator. My PV is dc coupled. To be clear there is or is not a NO SELL mode on SBI. Also I looked at specs and didn't see a PV DC input voltage or wattage . It did seem to say ac and array input the same up to 150v and I think up to 56 amp or 13.4 kw.
For now going to research the DEYS more.
 

the_colorist

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I dont want to run generator at all and definitely not at night unless grid down HOA with at least 5 acre lots. I will not sell to grid . I need grid for power when solar/battery not enough power. I plan to add more battery in steps to eventually 100kwhr or so. I do not and will not have Net Metering. I also do not want to charge batteries with grid at all. If grid down and not enough PV will use generator. My PV is dc coupled. To be clear there is or is not a NO SELL mode on SBI. Also I looked at specs and didn't see a PV DC input voltage or wattage . It did seem to say ac and array input the same up to 150v and I think up to 56 amp or 13.4 kw.
For now going to research the DEYS more.

So your looking for Grid-Zero with Grid-Backup. That's a little more difficult with Sunny Islands + Sunny Boys. @Hedges may have more input.

Victron can do it and Deye can do it. Not sure about MPP but I tend to avoid them so not familiar.

With Victron, you'll need to combine with Fronius PV inverters or DC -Couple for Grid-Zero. Or both (recommended). The advantage of Fronius is the 1000V PV input, among other things.

I'm sure your aware but only the Deye and the MPP are hybrids.

The Sunny Islands and the Victron inverters are just battery inverters.
 

the_colorist

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So your looking for Grid-Zero with Grid-Backup. That's a little more difficult with Sunny Islands + Sunny Boys.

Victron can do it and Deye can do it. Not sure about MPP but I tend to avoid them so not familiar.

With Victron, you'll need to combine with Fronius PV inverters or DC -Couple for Grid-Zero. Or both (recommended). The advantage of Fronius is the 1000V PV input, among other things.

I'm sure your aware but only the Deye and the MPP are hybrids.

The Sunny Islands and the Victron inverters are just battery inverters.
I should clarify, it can also be done with the European SMA Sunny Islands. Would need an auto-transformer.
 

TKB4

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So your looking for Grid-Zero with Grid-Backup. That's a little more difficult with Sunny Islands + Sunny Boys. @Hedges may have more input.

Victron can do it and Deye can do it. Not sure about MPP but I tend to avoid them so not familiar.

With Victron, you'll need to combine with Fronius PV inverters or DC -Couple for Grid-Zero. Or both (recommended). The advantage of Fronius is the 1000V PV input, among other things.

I'm sure your aware but only the Deye and the MPP are hybrids.

The Sunny Islands and the Victron inverters are just battery inverters.
Yes I am aware . I have 2 5,000 watt 450 watt charge controllers that I am currently using elsewhere that I could use but would rather not. The MPP units are hybrid units that cannot expos to grid at all and they cannot blend grid power either . They will overload and changeover to grid then check at intervals ? 5 minutes to see they can restart and handle the load. The point is the pair of MPP lv6548 s in parallel are capable of continuous 13kw and states 2 times rated power for 5 seconds which should meet ny requirements This should meet my requirements once soft start installed or 3 MPP lv5048 s should but more complicated and more standby draw. I think I would still rather have the DEYES but will continue research.
Thanks again.
 

the_colorist

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I completely get where you are coming from with grid blending. Deye inverters do 2 forms of Grid-Zero so you should be covered:

1610238513798.png
Their zero-export functions will keep the grid connected at all times (hence grid zero) but the grid will assist large loads and start-ups that exceed the capacity of inverter. The question then would be if you want to use LoadFirst or BattFirst.

Deye maximum pass-through is 50A or 12KW @ 240V.

I'm sure you're aware of this but:

2x MPP LV6548 in parallel simply creates 120V single phase so 13KW @ 120V.

2x LV6548 in a split-phase 120/240V configuration provides 6.5KW per leg. Based on the specs it looks like 13KW @ 240V but 6.5KW @ 120V. I'm guessing at this but based on the architecture it's likely. As far as I know they don't have an LF transformer to handle the phase imbalance. You could add a transformer externally for this.

It's the same with the Deye it appears. They state the 8KW model provides 33.4A @ 240V. It's likely that means 4KW @ 120V. May not matter for you but something to keep in mind. A $300 AT from Solaredge would give you 25A+33.4A or 58.4A @ 120V. This steps things up to roughly 7KW per leg, assuming the other leg had the excess power to handle it.

The LV5048 appears to be split-phase so parallel 120/240V works. Max 40A grid bypass (9.6KW) per unit. Not sure the topology but likely the same phase issue.

With the Deye the grid-charge for nights when the battery is low is a little unclear. It appears possible to configure grid charging when the SOC hits 30%. If you wanted to keep your grid usage as low as possible, you could set the grid charging current for something very low like 4A or so. 0A may work but would need to test to confirm.

1610241204258.png
 

Hedges

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Sunny Island can be off-grid with a generator.
So your looking for Grid-Zero with Grid-Backup. That's a little more difficult with Sunny Islands + Sunny Boys. @Hedges may have more input.

If configured for off-grid + generator, Sunny Island with Sunny Boy will disconnect relay to prevent backfeed into generator and raise frequency to control output of Sunny Boy.
If the input is actually utility grid not generator it should do the same thing. I'm not sure what it would do with only DC not AC coupling since no backfeed would occur.
If "Generator Request" signal closed an external relay to connect grid, for all SI knows the grid is a generator.

I recommend having some/most PV AC coupled with Sunny Boy. Their inverter capacity is added to Sunny Island's, the PV --> AC path is higher efficiency, and it allows battery charge current to be set very low if battery bank is undersized.

Looks like there is a parameter to turn grid feeding on/off vs. just charging from grid:

"Operating mode "Grid Charge"
Under specific conditions, the system can also temporarily feed energy from the stand-alone
grid into the utility grid in the operating mode GridCharge (parameter "232.08 GdMod")."

GridFeed.jpg"
 
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TKB4

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I completely get where you are coming from with grid blending. Deye inverters do 2 forms of Grid-Zero so you should be covered:

View attachment 32642
Their zero-export functions will keep the grid connected at all times (hence grid zero) but the grid will assist large loads and start-ups that exceed the capacity of inverter. The question then would be if you want to use LoadFirst or BattFirst.

Deye maximum pass-through is 50A or 12KW @ 240V.

I'm sure you're aware of this but:

2x MPP LV6548 in parallel simply creates 120V single phase so 13KW @ 120V.

2x LV6548 in a split-phase 120/240V configuration provides 6.5KW per leg. Based on the specs it looks like 13KW @ 240V but 6.5KW @ 120V. I'm guessing at this but based on the architecture it's likely. As far as I know they don't have an LF transformer to handle the phase imbalance. You could add a transformer externally for this.

It's the same with the Deye it appears. They state the 8KW model provides 33.4A @ 240V. It's likely that means 4KW @ 120V. May not matter for you but something to keep in mind. A $300 AT from Solaredge would give you 25A+33.4A or 58.4A @ 120V. This steps things up to roughly 7KW per leg, assuming the other leg had the excess power to handle it.

The LV5048 appears to be split-phase so parallel 120/240V works. Max 40A grid bypass (9.6KW) per unit. Not sure the topology but likely the same phase issue.

With the Deye the grid-charge for nights when the battery is low is a little unclear. It appears possible to configure grid charging when the SOC hits 30%. If you wanted to keep your grid usage as low as possible, you could set the grid charging current for something very low like 4A or so. 0A may work but would need to test to confirm.

View attachment 32648
Even more help. I finally got through most everything I could find on the DEYES. Luckily I already knew a lot about the Solark units. I am aware of the leg imbalance possibility but I can deal with that since most of the large power uses are 240v and essentially equal on each leg.My other loads would generally be about 1,000 watts and at most around 2500 watts . I might even be able to get by with a single DEYE 8k unit with grid or generator available with some load management. I know all the arguments for solark and have reviewed all of the posts in one of the other threads you post on regarding the DYE vs SBI etc. At least if I had 2 DYE 8k Would have a backup if only one has problems but I also know in parallel they would be likely to both be damaged in many circumstances but I could also do ok with generator alone if grid down.I I wouldn't need much extra surge capacity to start things anyway with 2 8k units. I would also have plenty of PV input for expansion and at high voltage .
 

TKB4

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Just an update . I did measure the inrush current and its 99 amps. I ordered the hyper engineering 230v 16-32 FLA model soft start unit and hopefully it will be here in 10 days or less. I made it start in 2 stage also and higher I could get was 118A in reality it will never do this. I should be able to get the starting amps down to about 30A which would make any inverter of 10,000 watts continuous rating or so good for my needs but 12kw or 13 kw would be even better so will see what the Inrush is with the soft start installed before proceeding further.
 

TKB4

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Another update: I installed the SureStart sot starter from Hyperengineering yesterday . It did even better than they claimed that it would!
The inrush amps on stage one of the 2 stage scroll compressor 5 ton climate master Tranquility 30 unit was 99 to 103 amps on several measurements. After the surestart was installed the inrush maximum amps went down to 24.4 AMPS !! a whopping 75% decrease !!!
I am extremely happy with this now not only can I start it easily with solar I can start and run it with only one 5,000 watt inverter and also my 5500 watt generator can run my whole house including HVAC in a total outage
 

TKB4

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OK now I have a headache. So a soft-start and a hard-start have the exact same objective, but using different hardware. Where the names are polar opposite. And there is an easy-start. Is it 5:00 yet?
not exactly
A HARD START kit does generally reduce the starting amps by say 15-25% . Its not by providing a lot of stored up power in the capacitor that is what happens in DC systems in AC systems it does it by advancing the phase of the current applied. These units may or may not extend the life of say a new compressor. They are generally used when a compressor is drawing over spec current or wont start at all. So they are usually used at end of life of a failing compressor to keep it going longer until a new unit or compressor is eventually installed but this could be years in some cases. They can also reduce light flicker at startup just like anything that reduces max current draw would. a Hard Start that uses a potentiometer is generally considered better like Kickstart or 5-2-1 and others. They might extend newer unit life by some less amps to start winding of motor. These are generally around $30 to $40.

A SOFT START unit reduces the starting amps in the neighborhood of 60-70 % most of the time . It is much more expensive in the neighborhood of $250 to $400. There are 2 major brands Microaire and Hyperengineering. some other brands like Emerson were rebranded. I think there are other european brands also. Soft starters in general introduce inrush current limiters of the right power rating and resistance to the start winding of the motor. Here is a link to a simple homemade one and demonstration
The soft start learns over several cycles of compressor starting when it can apply the least number of amps to start the motor. I suspect it has a circuit board that determines how much resistance is needed then electronically provides just the correct amount and probably also adjusts the phase to afford the least starting amps. It also provides a restart delay similar to the unit about 15-30 times an hour which I suspect is to allow its internal components to cool. Since it limits the current so much and applies it at the best time They are generally recognized to extend the life of the compressor or motor they are used on . As a side benefit I can attest mine reduced the startup noise of an already quiet compressor/unit.

In summary the big differences
Hard Start reduces starting amps some by advancing the power curve and may help the life of compressor but used mainly to start a failing compressor and costs much less.
the Soft Start units are smart units and use inrush limiters (usually NTC s) to reduce the inrush current close to the optimum amount and adjust the phase also to limit the current used and are much more expensive. Think of them as a Smart Start Capacitor and are much more expensive.
 

HateGrid

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I am considering the Deye SUN-8K-SG01LP1-EU inverter for house and workshop in New Zealand (240V 50Hz).

The extra paperwork, new export meter, electrical inspections, and electricians to do grid export isn't worth it given that I pay between $0.18 and $0.27 / kWh and only get $0.08 for feeding back to the grid.

So, if I don't go through all of the paperwork to meet the export compliance, am I able to treat this as an off-grid inverter or am I limited by the fact that it is capable of feeding power back, so I have to go through the AS4777 certification just in case?

There is an option to connect the grid to the generator, although there probably isn't much of an electrical difference based upon this basic schematic.


1611663822868.png
 

TKB4

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I cannot speak to the law or codes there but the inverter reportedly has settings to prevent it from back feeding the grid in a no sell mode . I would think as long as it is used in this "off grid only mode" you should not have a problem using it. I hadn't really thought about hooking grid input to the generator connection but surely the inverter would never backed a generator so I suppose you wouldn't have to worry about accidentally changing the settings that might allow it to back feed. There may be other consequences of hooking grid to generator connections such as a change in "Bypass " total wattage or different battery charge parameters etc but that is a different question I think you can resolve from the spec sheet. If it cannot back feed the grid I am not sure what they would be able to say about it just because its capable of doing it but doesn't. If it didn't require inspection just for installation etc not sure that anyone would ever find out but you would likely be liable if somehow it did back feed the grid.
BTW We want to New Zealand and Australia many years ago on our honeymoon. Its a beautiful country both North and South .
 

TKB4

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BYW I failed to mention and now too late to edit the 3 rd post above. The soft starter may also use frequency manipulation similar to a Variable Frequency Drive but its just speculation. I just know it works impressively.
 

HateGrid

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If it cannot back feed the grid I am not sure what they would be able to say about it just because its capable of doing it but doesn't. If it didn't require inspection just for installation etc not sure that anyone would ever find out but you would likely be liable if somehow it did back feed the grid.
Unfortunately, it does require an inspection from an independent electrical inspector for the PV side >120VDC and anything on the AC side has to be hooked up by an electrician. So I have to convince them that everything is fine.

Since I posted this, I found a power company that will buy/sell power at the spot price, so that changes the equation and I'll likely go through the hassle of doing grid tied.

BTW We want to New Zealand and Australia many years ago on our honeymoon. Its a beautiful country both North and South .
I hope you had a pleasant stay! I am on the South Island a little south of Christchurch.
 

TKB4

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Unfortunately, it does require an inspection from an independent electrical inspector for the PV side >120VDC and anything on the AC side has to be hooked up by an electrician. So I have to convince them that everything is fine.

Since I posted this, I found a power company that will buy/sell power at the spot price, so that changes the equation and I'll likely go through the hassle of doing grid tied.


I hope you had a pleasant stay! I am on the South Island a little south of Christchurch.
good that would be beneficial in the long run depending on expense since you wouldn't need to rely near as much on battery and the inverter is capable of it anyway. Yes We loved it!
 

HaldorEE

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Unfortunately, it does require an inspection from an independent electrical inspector for the PV side >120VDC and anything on the AC side has to be hooked up by an electrician. So I have to convince them that everything is fine.

Since I posted this, I found a power company that will buy/sell power at the spot price, so that changes the equation and I'll likely go through the hassle of doing grid tied.


I hope you had a pleasant stay! I am on the South Island a little south of Christchurch.
I would forgo batteries then unless power outages are a major issue. Better to just buy more panels and get yourself to net zero.
 

TKB4

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I agree not to concentrate on batteries initially and better to invest in more panels now but I personally would still want at least a small amount of battery backup even if it had to be lead acid with batteries outdoors or even charge them with plug in grid and just hook them up during outage if thats easier. Of course if lithium no need. You can of course start with no batteries then buy whatever you feel economical later.
 

HateGrid

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I agree not to concentrate on batteries initially and better to invest in more panels now
Agreed. After I looked at the price of panels, I decided to fill the entire roof space which works out to 34 panels (1960mm x 990mm), so around 13.9KW depending upon the efficiency. I'll be swimming in power during the summer and will still be short during the winter due to only getting an average of 1.29 KWH/m2 during winter. I'll go with the PERC panels to make use of the lower light-levels. It seems even on cloudy days the irradiance is still around 400 W/m2.

would forgo batteries then unless power outages are a major issue. Better to just buy more panels and get yourself to net zero.
Yes, I lose power for at least an hour every few months. I work from home, so any loss of power more than about 15 minutes stops my work since the UPS batteries are small.

We also have the issue of earthquakes. If we get the big one here (Alpine Fault) which is overdue, then there is a risk it damages the transmission lines that run over the fault and we are out of power for a few months.

The spot prices are such here that it actually pays to store power at night in batteries and feed back to the grid during the day (in addition to solar feed-back). I've applied for the spot-price plan last week, but I'm still waiting to find out if it will be accepted.
 

HateGrid

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Also forgot to mention, I have a single phase 15KW (240V, 63A) connection, but need 10KW of 3-phase intermittently for the workshop. The batteries help here since I can use an off-grid 3-phase inverter and not risk blowing the main breaker if my wife decides to make a cup of tea (which is a 3KW kettle) while I'm using the machines in the workshop. All of the 3-phase hybrid inverters (and single-phase paralleled hybrid inverters) that I've seen require a 3-phase main connection unless they are in off-grid mode.
 
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