Sol-Ark 12k Limited to Home mode questions

[AmpLee]

So if I'm understanding the Limited to Home mode correctly, the Sol-Ark will use PV (and battery under time of use settings) to power the home panel while using the grid to fill in when needed. This would be ideal for me since I do not want to deal with a grid-sell contract.

My question is what happens under an acute load (or multiple heavy loads), say an instant hot water heater and jet pump being turned on simultaneously? Does the sol-ark still provide power from pv/battery while the grid fills in the rest of the load, or does the Sol-Ark direct the grid to completely power that particular load because it's too big for the sol-ark to handle alone?

If I'm in the limited to home mode, do I need a critical loads panel or can the sol-ark just power the main home panel and I can manage loads under a grid down situation?

Also, my main panel is about 100 feet from the Sol-Ark, what limiter sensor wires should I run. In the manual it says 23 awg cat-6, but elsewhere it says 20 awg. I'm a bit confused here.

 

[Ted Katsouras]

I have the same setup with Sol-Ark, Sol-Ark can provide 12K max to the critical loads panel but there is no limit to the loads on the main panel other than the limit of the Main panel, on grid down situation the power to the main panel will be off but the critical loads panel will work fine.
A friend of mine is using the CT sensors with 100 feet run from the main panel to the Sol-Ark with no problem he is using 20 AWG TP wire and he tried to routed away from other wires so does not pick up much noise.

 

[silencedogood]

It only has a 63 Amp breaker on the grid side, so the limit would be 63 amps max being backfed into the main panel

 

[Sanwizard]

I have the same setup with Sol-Ark, Sol-Ark can provide 12K max to the critical loads panel but there is no limit to the loads on the main panel other than the limit of the Main panel, on grid down situation the power to the main panel will be off but the critical loads panel will work fine.
A friend of mine is using the CT sensors with 100 feet run from the main panel to the Sol-Ark with no problem he is using 20 AWG TP wire and he tried to routed away from other wires so does not pick up much noise.

I thought the Sol-ark 12K is actually 9K AC out max? (12K is PV in?)

 

[AmpLee]

I thought the Sol-ark 12K is actually 9K AC out max? (12K is PV in?)

That is correct. It can do 9k to loads and 3k to batteries.

 

[Ted Katsouras]

The specs states:
continuous AC power with Grid or Generator 15KW or 63A.

 

[Keith Moreau]

If you want to be able to use the Sol-Ark off grid, it's best to have the LOAD output of the Sol-Ark directly connected to your critical loads panel (or potentially your main panel but it would be a small panel). If you only use the Sol-Ark GRID input / output, because it is a grid-tied inverter, when the grid is out, it senses if there is no grid power and will disable any power output to the GRID out. If the grid goes down, the Sol-Ark would be able to still power the LOAD output though from PV and battery but nothing to the GRID output. This is a feature of any 'legal' grid-tied inverter. It cannot send out power when the grid is down. This is to prevent potentially dangerous current from coming out of your house and going into the power lines outside your house.

So basically, if you want to use the Sol-Ark in the way it was intended in a grid down situation, you'll really need a separate critical loads panel. If you just want the Sol-Ark to do what it can with PV and Batteries to supplement your utility power and use your whole house circuit breaker panel, it will work by connecting the Sol-Ark's GRID output to your service mains with what is called a tap. There are a lot of settings but basically, if there is PV and battery, you can set it to use a combination to supply as much power as it can up to 9000w AC output and another 3K DC from PV to charge the batteries. Once you get more than 9KW AC (or is it 9.6KW?) of load then it would draw the remainder from the grid.

I've heard that you can use the GEN input on the Sol-Ark to add more AC to the system, I think where this 15KW figure comes from, it would allow you to 'pass-through' an AC-Coupled PV system, or generator to supply more than 12KW. However, in talking with their support, I'm not sure if this is really true, I haven't good answer from them yet. I have about 12KW of potential PV going into my Sol-Ark's MPPTs. When I asked if I could supplement this with a 'grid-tied' inverter (powered by a separate PV array) into their GEN input to get another 3K out of the Sol-Ark they said no, I'm at my limit. I shouldn't add any more power into the Sol-Ark. I don't know if this was entirely true or not though. Their marketing and webinars though make it seem like it is possible, and it is a feature.

All in all, I'm happy with the Sol-Ark, I have a few little anomalies with the limited to home mode. It seems that sometimes, when there is a large load (such as charging a Tesla) it won't use all the available PV and will draw from the battery and / or grid instead which is a waste. Conversely, sometimes when there isn't' enough PV to supply the load, it uses the Grid instead of the battery, even though I believe I have it set to use battery for any loads. This is a continuing conversation I'm having with Sol-Ark's tech support.

 

[AmpLee]

If you want to be able to use the Sol-Ark off grid, it's best to have the LOAD output of the Sol-Ark directly connected to your critical loads panel (or potentially your main panel but it would be a small panel). If you only use the Sol-Ark GRID input / output, because it is a grid-tied inverter, when the grid is out, it senses if there is no grid power and will disable any power output to the GRID out. If the grid goes down, the Sol-Ark would be able to still power the LOAD output though from PV and battery but nothing to the GRID output. This is a feature of any 'legal' grid-tied inverter. It cannot send out power when the grid is down. This is to prevent potentially dangerous current from coming out of your house and going into the power lines outside your house.

So basically, if you want to use the Sol-Ark in the way it was intended in a grid down situation, you'll really need a separate critical loads panel. If you just want the Sol-Ark to do what it can with PV and Batteries to supplement your utility power and use your whole house circuit breaker panel, it will work by connecting the Sol-Ark's GRID output to your service mains with what is called a tap. There are a lot of settings but basically, if there is PV and battery, you can set it to use a combination to supply as much power as it can up to 9000w AC output and another 3K DC from PV to charge the batteries. Once you get more than 9KW AC (or is it 9.6KW?) of load then it would draw the remainder from the grid.

I've heard that you can use the GEN input on the Sol-Ark to add more AC to the system, I think where this 15KW figure comes from, it would allow you to 'pass-through' an AC-Coupled PV system, or generator to supply more than 12KW. However, in talking with their support, I'm not sure if this is really true, I haven't good answer from them yet. I have about 12KW of potential PV going into my Sol-Ark's MPPTs. When I asked if I could supplement this with a 'grid-tied' inverter (powered by a separate PV array) into their GEN input to get another 3K out of the Sol-Ark they said no, I'm at my limit. I shouldn't add any more power into the Sol-Ark. I don't know if this was entirely true or not though. Their marketing and webinars though make it seem like it is possible, and it is a feature.

All in all, I'm happy with the Sol-Ark, I have a few little anomalies with the limited to home mode. It seems that sometimes, when there is a large load (such as charging a Tesla) it won't use all the available PV and will draw from the battery and / or grid instead which is a waste. Conversely, sometimes when there isn't' enough PV to supply the load, it uses the Grid instead of the battery, even though I believe I have it set to use battery for any loads. This is a continuing conversation I'm having with Sol-Ark's tech support.

Thanks for your reply.

Which Sol-Ark model do you have?

I just replaced my 61v model with a 63v outdoor model and there was a new menu option in the advanced tab titled "CT ratio". This parameter was the difference in some really strange behavior with my Sol-Ark and some relatively normal behavior. But, like you, I am having some issues with grid power coming in on higher loads. I've pretty much poured over all the setting that could be user error and have come to the conclusion that it's something with the Sol-Ark. When I'm charging my EV at a higher load, the Sol-Ark is pulling 400w from the grid even though there's plenty of energy still available in my PV panels and the batteries. This is pretty frustrating as it's zeroing out the meter during normal lighter loads. The only setting that was odd was the CT ratio which mine needed to be set at 200 for the Sol-Ark to register the most normal behavior, but still not working the way it should.

Have you had any resolution to your abnormal behavior?

 

[Bullitt]

If you just want the Sol-Ark to do what it can with PV and Batteries to supplement your utility power and use your whole house circuit breaker panel, it will work by connecting the Sol-Ark's GRID output to your service mains with what is called a tap. There are a lot of settings but basically, if there is PV and battery, you can set it to use a combination to supply as much power as it can up to 9000w AC output and another 3K DC from PV to charge the batteries. Once you get more than 9KW AC (or is it 9.6KW?) of load then it would draw the remainder from the grid.

Thanks for posting this, this is similar to the use case I am shooting for and it's good to see that it may be possible.

I want to limit the draw from the grid to the maximum degree possible during the day, and charge batteries (and run very large loads like an EV charger at night as well) from the grid at night. This is to take advantage of nearly free power from the grid at night (and to avoid very expensive grid power in the day).

I had thought this could be handled by the time of use mode, but my daytime loads may (rarely) exceed the 9KW the Sol-Ark can output. So if I wanted to ensure smooth operation with all the loads I want, I would need two 12K Sol-Arks. That is expensive, but if I were to move the A/C (for example) from the panel the Sol-Ark is feeding, I would pretty much always be under 9KW, but then that A/C would be drawing from the grid 24/7. If what you mention above is feasible, and can be used in conjunction with time of use mode (but maybe you have to choose time of use OR limited to home mode?) , that would be the best of both worlds for me. What are the settings/wiring that you would need to use to get this done?

B

 

[AmpLee]

Thanks for posting this, this is similar to the use case I am shooting for and it's good to see that it may be possible.

I want to limit the draw from the grid to the maximum degree possible during the day, and charge batteries (and run very large loads like an EV charger at night as well) from the grid at night. This is to take advantage of nearly free power from the grid at night (and to avoid very expensive grid power in the day).

I had thought this could be handled by the time of use mode, but my daytime loads may (rarely) exceed the 9KW the Sol-Ark can output. So if I wanted to ensure smooth operation with all the loads I want, I would need two 12K Sol-Arks. That is expensive, but if I were to move the A/C (for example) from the panel the Sol-Ark is feeding, I would pretty much always be under 9KW, but then that A/C would be drawing from the grid 24/7. If what you mention above is feasible, and can be used in conjunction with time of use mode (but maybe you have to choose time of use OR limited to home mode?) , that would be the best of both worlds for me. What are the settings/wiring that you would need to use to get this done?

B

You feed 6-4 wire from your Sol-Ark's Grid breaker into a 60 amp breaker in your main panel and run CT sensor wires to your incoming main lines inside the main panel. This will enable the ability to use the limited to home mode which will zero out your meter prioritizing solar>battery>grid using time of use settings. This means that all of your loads in your main panel, the Sol-Ark will feed as much power as it has available to power these loads and use the grid as a the backup or to fill in where loads are too high for the Sol-Ark. However, these loads will be unavailable in a power outtage and only the loads in your critical loads subpanel will be available so if you move your AC unit over, it will not work in a power outtage. That said it certainly seems possible to back feed your main panel from your critical loads panel but you'd need some sort of interlock system that both shut off the main breaker as well as the breaker in main panel going to the grid breaker in the Sol-ark. I'm looking at a k-9010 interlock for the latter.

Just note that the CT wiring can be finicky. I had to actually reverse one of my sensors (arrow pointing towards panel instead of grid) to finally get the sensors to zero out my meter. Other than that, it's pretty easy.

 

[Keith Moreau]

@Bullitt : as mentioned above by AmpLee (I think of Rush fame?) There are a couple of choices when you're using the Sol-Ark in Grid Tie. If you you only use the 'Grid' In/Out of the Sol-Ark, you won't get 'off-grid' power at all if the Grid goes down. You'll tie the Sol-Ark 'GRID' in/out directly to your utility mains right after your meter. If you don't care about that, like your Grid is reliable, then maybe you don't need that. You'll be able to shift your grid power usage to non-peak cost times with little effort, you'll just have to program the Sol-Ark's time of use function to make sure the batteries can supply power when there isn't enough PV available to power your loads.

If you want to be able to be able to use the Sol-Ark PV and Batteries to power your house loads if the grid goes down, you'll have to connect the Sol-Ark's LOAD output. As a grid-tie inverter, the Sol-Ark will not attempt to draw or send power at all if it senses there is no power from the grid. Then the simplest solution is to have a Critical loads panel directly connected to the the LOAD output. In the event of a power outage you'll get a seamless transition from Grid +Solark power to just Sol-Ark "LOAD" output power. However, in non outrage situations you'll be limited around 12KW of total power available to the critical loads panel. This might not be enough to power all your stuff at once and it adds complexity to your system, because you'll have to add another circuit breaker panel to your system for either the critical loads or the non critical loads.

If you don't need the 'seamless' transition from on Grid to off grid, then, as Amp Lee said, you could put in a 'transfer switch'. This ensures that you can still have your house powered if the utility grid is down. You'll have to connect this switch in between your Sol-Ark "LOAD" output and your Circuit breaker panel. It will interrupt the utility power and switch your breaker panel to use the Sol-Ark's LOAD output. It's not seamless. Your home will be without power for a time from when the grid goes out and you switch the transfer switch.

The transfer switch ensures that you Sol-Ark's "LOAD" output is never connected to the utility and/or the Sol-Ark GRID in/out. It is potentially bad for your Sol-Ark if this happens, and could be dangerous for utility workers working on power lines they think are dead. There are tons of transfer switches out there, including some that are built into breaker panels, usually meant for generators, but can be used for the Sol-Ark's LOAD output. They include a mechanical interlock, which physically prevents the 2 sources of power to be connected together at the same time.

If money and time/complexity is no object, then paralleling multiple Sol-Arks is probably the most elegant solution. You just never have the Grid directly connected to your house breaker panel. You'll have up to 24K(or more depending on how many So-Arks you have) to power your loads at once during a utility outage, and if there is a outage, and you have enough PV/battery power, the transition to 'off grid' will be seamless. You'll also be able to add more PV to your system, which is an added benefit.

One caveat of paralleling multiple Sol-Ark's is that each Sol-Ark can only produce about 4500 watts of power per phase of the 240V split phase 120v. If your loads are unbalanced, ie if you power on 120V devices on one phase / leg that total more than 4500W, then the Sol-Ark will overload and shut down. The paralleling of Sol-Ark's uses a communication channel between them but the load balancing is not perfect or instantaneous. Your unbalanced loads may peak above 4500 for a short time but will trip your Sol-Ark and it will shut down. A properly wired 'autotransformer' can help with unbalanced loads to keep this from happening, even when using a single Sol-Ark.

Hope this all helps.

 

[Sanwizard]

Thank you for that great overview.

 

[Keith Moreau]

@Sanwizard You're very welcome. I failed to mention that there is also the "GEN" input / output on the Sol-Ark. When reconfigured in the settings from a Generator input to a 'Smart Load' output, the Sol-Ark redirect excess PV power when available to loads that are not critical but could be run periodically at any time, for example, pool pump, well / water tank pump, HVAC, water heater. I think this could be more desirable in an off-grid situation where the batteries are full, your EV is fully charged, but there is still extra PV available. If you aren't grid-tied with some type of net metering agreement in place or during a utility outage, you won't be able to pump excess PV to the grid, and this is where the Smart Load can squeeze a little more out of your system. Feel free to keep the questions coming.

 

[Bullitt]

Thanks to both for taking the time to reply, this is precisely what I was looking for.

In my use case, I don't need to worry about back-feeding from the critical loads to the main panel; I'm fine with the A/C not being available when the grid is down as long as in normal operation the Sol-Ark can help off-set that demand in the main panel.

It sounds like the part I was not understanding was that the "Grid" breaker on the Sol-Ark is bi-directional (i.e. capable of back-feeding the main panel).

 

[bedpan]

Just want to say thanks to all for the comments here. I am looking at something similar and it answers some of my questions.. Thanks to those who took the time to input!