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Sol Ark 12k Off Grid with small generator - peak shaving

mvonw

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Does anyone have any experience with the Sol Ark 12K and using a small generator to supplement the PV?
I have my Honda 65000 240v generator connected to the Sol Ark's Grid terminals and the configured to use Gen to Grid setting. Using the latest firmware from SA.

The generator charges the batteries fine except if I put a big load on and then it overloads the generator and trips the generator breaker (on the Honda).

In an attempt to correct this, I wanted to try generator peak shaving.
I put CTs on the two legs (arrow facing generator) and connected it to SA. I then configured this interface
1657149194352.png
To use grid peak shaving and set the value to 5500 Watts (not 9k). When I did this the inverter would only draw a few amps from the generator and did not seem to respect the peak shaving setting.

I called SA support and asked what the heck is the difference between Gen Limit Power and Grid Peak-shaving and the support person did not know either!! Apparently they are intended to do the same thing, but I'm not entirely clear on that..

Can someone with a similar setup explicate this?
 
did you get an answer to your questions? I was planning to have a small generator charge my batteries while using only the batteries to power 4T central air.
Is it possible to have the Sol-Ark set up that way so that the high rush-in current during the compressor start is only coming from the batteries instead of stalling the small/ less powerful generator?
 
I did not get a definitive answer, just some things to 'try' from Sol Ark. I believe that is exactly what the peak shaving is for when a generator is involved. I haven't had time to fiddle around with it yet. What's interesting is that my Honda is rated for 5500 watts running, and that is exactly what the SolArk pulls from it if there is no load, just charging batteries. For simple battery charging, that's great (except the gas cost at running a generator at full tilt for 3 hours!!) . What I don't understand is how to keep the generator from going over 5500 watts if I apply load to the Sol Ark....
 
I see. Yea, would be great to be able keep the gen at 50% of max power if the goal is just to charge the battery. That would save gas (especially now) and not too taxing on the gen itself. That's what I'm looking for. Just a plan B to charge my batteries when the panels are not producing.
 
What bothered me is that the Sol Ark Tech Rep could not even explain what the "Gen Limit Power" setting did. I don't think it has anything to do with the CT's apparently.
 
I don't remember his name. He seemed tentative in his responses and knowledge of the settings. My sense he was new. I've called them 3 or 4 times and always gotten different people. Like everyone else, they probably have recruiting/retention issues with staff.
 
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There are two things that can cause a momentary excessive surge AC load pass through back to AC input.

Both Low freq and High freq inverters have a recognition and response time to react to exceeding AC input current setting. A sudden heavy AC load will momentarily exceed the set AC input limit current before inverter reacts and takes up the excessive load. To complicate this process the inverter may only need to back down charging current load on AC input to leave enough pass-through AC input current to supply peak surge AC output load.

HF inverters have a second problem in their ability to switch their battery to HV DC converter from charging to supplying AC output from battery. Sol-Ark and Deye have a large bank of HV DC capacitors to provide a reserve cushion to quickly supply the sudden AC load surge demand, but it has its limits. Too much surge will slump the HV capacitor voltage causing the AC load to show up on AC input. Once the battery to HV DC converter makes its power direction change it takes up the AC output load.

Sometimes you can lower the maximum AC input limit to give the inverter an early warning, so it starts the process sooner reducing the severity of AC load leak through to AC input source. Victron LF inverter has a function called 'Dynamic AC input limiting' which looks at rate of rise in AC input current and starts the inverter supplementing before AC input current limit is reached. Once load has settled it backs off inverter supplementing turning load back over to AC input, up to any maximum limit setting.

Synchronous generators react differently to overload than inverter-generators. A synchronous generator mechanically bogs down which can cause an AC output frequency drop. If generator changes AC frequency too quickly the hybrid inverter cannot track the freq shift and just releases from generator. An inverter-generator will keep freq constant, but the peaks of inverter-generator's sinewave waveform will be clipped. For an inverter-generator it is better not to enable rpm reducing ECO mode if AC load surge is expected, like starting an AC motor. Spinning up the engine rpm to meet the increased power demand takes a relatively long time.
 
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I don't remember his name. He seemed tentative in his responses and knowledge of the settings. My sense he was new. I've called them 3 or 4 times and always gotten different people. Like everyone else, they probably have recruiting/retention issues with staff.
When you call about complicated issues ask the person are they part of the original team or the new tech team.
Most of the old team guys have been there since the Inverter was being designed. The new guys have only been there about 6 month and they don't have experience with the really unusual features.
 
I would think the Gen Limit Power number is the max amount of power that the sol-ark would let the generator provide to the system. So, you enter 3000W and the generator would set itself to provide that amount of power to the system even if the home is using more via a battery bank. Am I wrong?
 
I would think the Gen Limit Power number is the max amount of power that the sol-ark would let the generator provide to the system. So, you enter 3000W and the generator would set itself to provide that amount of power to the system even if the home is using more via a battery bank. Am I wrong?
Ha, that's what I assumed and asked that directly to the support rep. He said Grid Peak Shaving (when generator is set to Grid input, that is) is the setting that controls the limits on the generator via the CT's. He could not really explain what the Gen Limit Power does other than it was a new feature that they implemented for specific use cases that he wasn't sure of. As far as I have been able to tell so far, the Gen Limit Power setting has no bearing the wattage from the generator, but I've not tinkered with it enough to be certain either. For now, as long as I don't load my system while charging via Gen, I'm fine. Worst case is the Generator breaker trips and I have to reset it. Eventually, I hope to get this figured out.
 
Ha, that's what I assumed and asked that directly to the support rep. He said Grid Peak Shaving (when generator is set to Grid input, that is) is the setting that controls the limits on the generator via the CT's. He could not really explain what the Gen Limit Power does other than it was a new feature that they implemented for specific use cases that he wasn't sure of. As far as I have been able to tell so far, the Gen Limit Power setting has no bearing the wattage from the generator, but I've not tinkered with it enough to be certain either. For now, as long as I don't load my system while charging via Gen, I'm fine. Worst case is the Generator breaker trips and I have to reset it. Eventually, I hope to get this figured out.
Unit has internal CT's. External CT's are only required when you want to back feed to supplementally supply main panel loads while still preventing inverter from pushing any power to utility grid. You need extra external CT's to check the current coming and going directly from utility grid connect lines. This is to keep zero export or utility regulated level of export to utility grid.

Both grid and gen inputs on SolArk have internal CT current measurements. They have independent limits. Only one input can be used at a time and it becomes the inverter phase master reference. Obviously, generator cannot export power to grid because there is no way to synchronize generator to grid. Generator input does not allowed any export of PV generated power as that would be bad for generator. PV power can be used to supplement AC out power when operating on a generator, just like battery power can be used to supplement AC output power.
 
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Unit has internal CT's. External CT's are only required when you want to back feed to supplementally supply main panel loads while still preventing inverter from pushing any power to utility grid. You need extra external CT's to check the current coming and going directly from utility grid connect lines. This is to keep zero export to utility grid.
Hmm. That’s interesting, but I don’t think it aligns with what the manual (or tech rep) say. Do you have a Sol Ark 12K?
This is directly from the Sol Ark Manual:

Grid Peak Shaving Mode (For Gen Connected to Grid Breaker)
A. Prevents the Sol-Ark from overloading generators
B. Must place the CT sensors so that they measure L1 and L2 of the
generator's output, pointing arrows on the CTs towards the generator
C. Sol-Ark contributes power above the "Power" value threshold to prevent
overloading the generator
D. This mode will auto-adjust the Grid Charge Amperage to avoid overloads
 
Maybe that's for situations where the generator is running multiple things and not just the inverter
 
Well, this setup is specifically for small portable generators connected to the Inverter, but indirectly, yes, the generator is supplementing current to the Inverter, but most people use it for charging
 
Here are my observations on this topic. Support from SolArk customer service on this setup is thin at best. I have not found anyone there who can adequately describe how this was supposed to work or how to set it up. The manual has some hints but reads like the author did not not know what to write which leads to misconception of the OP. The below represents my personal observations after hours of testing as I want to accomplish what the OP wants.

While I am pretty good at observing take everything with the appropriate grain of salt.

I have been experimenting with my SolArk 12KOD setup having a generator connected to the 'gen' input, my house connected to the 'load' input and the 'grid' input unconnected. My inverter firmware is M 6.2.1.1 / S -- / C 1.4.3.0 and the notes below refer to this mode of operation and this firmware.

With this setup you can charge your batteries and support the load with your generator. You cannot supplement your generator in supporting the load. It would be really cool if you could supplement your generator with the inverter as the OP discussed but the software does not support this today. You can only charge and not discharge. The manual should be updated to clearly reflect this until it does.

So this leads the number one issue in selecting a generator. Your "small" generator must be able to totally support the load in addition to any charging you want to do. As discussed above there is a setting to limit the power from the generator and this feature does work in that the battery charging will be reduced to keep the power under that threshold. However if the load is already requiring more than the threshold then your generator will trip even of the charging power is reduced to zero.

You do not need to install any CTs for gen input power limit to work. I can see the generator power on the status screen with my 12KOD with no CTs installed. I heard once that these gen input CTs are a new feature of the 12kOD compared to the 12K and possibly the 8K. Someone will need to report if they can see the generator power on the status screen with their 12K or 8K to confirm.

Another issue I have is that if you are charging your battery and supporting the load with your generator and a substantial load change is required, for example from your HVAC system coming on, then you are likely to experience an F18 AC overcurrent fault. I am not sure of the reason exactly but suspect that the sudden drop in AC frequency causes the inverter to loose its phase lock causing an overcurrent. So another requirement for your generator is to have stable frequency even in the face of a sudden change in the load. I suppose bigger gensets are better at this than smaller ones. I have tried a 4kW and 9.5kW portables without success.

Another issue you will have is the confluence of an offgrid feature like this and the TOU settings. I am not able to get the generator to connect unless I set the TOU master switch on and raise the battery voltage above the current battery voltage. This is opposite of what you want when you are in the ongrid mode. And as there is no automatic way for this setting to transition it seems impossible now to transition to off-grid mode during a power outage. Very confusing.

Its a shame that SolArk customer support does not have better information on exactly how their product works. It's a very capable inverter topology but the magic is in the software and if no one knows how it works or what it needs to do to satisfy their customers it does not bode well. If you want to operate on-grid or off-grid this inverter works. But if you want to transition back and forth there are issues and anyone who wants to do this should wait for the dust to settle IMHO. I would be much more encouraged if they knew this topic better at SolArk but as they don't I worry that it will be a long time before they recognize much less address the issues.
 
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Here are my observations on this topic. Support from SolArk customer service on this setup is thin at best. I have not found anyone there who can adequately describe how this was supposed to work or how to set it up. The manual has some hints but reads like the author did not not know what to write which leads to misconception of the OP. The below represents my personal observations after hours of testing as I want to accomplish what the OP wants.

While I am pretty good at observing take everything with the appropriate grain of salt.

I have been experimenting with my SolArk 12KOD setup having a generator connected to the 'gen' input, my house connected to the 'load' input and the 'grid' input unconnected. My inverter firmware is M 6.2.1.1 / S -- / C 1.4.3.0 and the notes below refer to this mode of operation and this firmware.

With this setup you can charge your batteries and support the load with your generator. You cannot supplement your generator in supporting the load. It would be really cool if you could supplement your generator with the inverter as the OP discussed but the software does not support this today. You can only charge and not discharge. The manual should be updated to clearly reflect this until it does.

So this leads the number one issue in selecting a generator. Your "small" generator must be able to totally support the load in addition to any charging you want to do. As discussed above there is a setting to limit the power from the generator and this feature does work in that the battery charging will be reduced to keep the power under that threshold. However if the load is already requiring more than the threshold then your generator will trip even of the charging power is reduced to zero.

You do not need to install any CTs for gen input power limit to work. I can see the generator power on the status screen with my 12KOD with no CTs installed. I heard once that these gen input CTs are a new feature of the 12kOD compared to the 12K and possibly the 8K. Someone will need to report if they can see the generator power on the status screen with their 12K or 8K to confirm.

Another issue I have is that if you are charging your battery and supporting the load with your generator and a substantial load change is required, for example from your HVAC system coming on, then you are likely to experience an F18 AC overcurrent fault. I am not sure of the reason exactly but suspect that the sudden drop in AC frequency causes the inverter to loose its phase lock causing an overcurrent. So another requirement for your generator is to have stable frequency even in the face of a sudden change in the load. I suppose bigger gensets are better at this than smaller ones. I have tried a 4kW and 9.5kW portables without success.

Another issue you will have is the confluence of an offgrid feature like this and the TOU settings. I am not able to get the generator to connect unless I set the TOU master switch on and raise the battery voltage above the current battery voltage. This is opposite of what you want when you are in the ongrid mode. And as there is no automatic way for this setting to transition it seems impossible now to transition to off-grid mode during a power outage. Very confusing.

Its a shame that SolArk customer support does not have better information on exactly how their product works. It's a very capable inverter topology but the magic is in the software and if no one knows how it works or what it needs to do to satisfy their customers it does not bode well. If you want to operate on-grid or off-grid this inverter works. But if you want to transition back and forth there are issues and anyone who wants to do this should wait for the dust to settle IMHO. I would be much more encouraged if they knew this topic better at SolArk but as they don't I worry that it will be a long time before they recognize much less address the issues.
You are definitely correct that nobody there seems to know how it works!! I finally got mine to work after a lot of trial and error. I’m 100% off grid, so I have my generator connected to the Grid input. When the generator is running, it both charges the batteries and support the loads. I pretty much only use it when the PV’s didn’t get a full charge. I ended up disconnecting the CTs and just adjusting the “A” value on the charge screen on the battery setup. I had to set the “Grid Charge” option, which is a bit confusing because I’m not using the Grid.

If the software and UI was properly implemented, it would show more appropriate labels on the setting values based on the actual configuration that you are using. This is especially important on a device like this that has so many different configuration options/modes.
They could save thousands of dollars in support calls and confused customers if they could Implement a modern, intelligent user interface, instead, it looks like it was designed by an engineer instead of real human being :)
 
Hello All

I was just looking into this and stumbled upon this thread. Incredible that SolArk themselves are not clear on the function of the "Gen Limit Power" setting. Wow!

My current system uses a 12K-P (outdoor) and 12kw in PV. It currently does not have a battery bank. It is a grid tied system with Net Metering as main priority to save on electricity bill. I already have an 11kw Generac Guardian stand by generator with ATS to power the house in the event of an outage, so at the time the added cost of a battery was hard to justify. However we planned on adding batteries in the future, so even thought the Gen breaker is OFF. The connection from the generator to the GEN input of the SolArk was made so I could use the remote Gen start feature to charge the batteries whenever implemented. Well that moment is now and just like the OP, I wanted to figure out if the "Gen Limit Power" setting does what I think it does since the manual doesn't tell you anything. After the batteries are installed the only situation where I would be using the generator would be when there is no Sun nor Grid and batteries below the set threshold. Realistically that would be sometime in the middle of the night during an extended outage. Currently the default value is 8kw, which would be fine as I don't want to pull the full 9KW AC the inverter can handle from the generator.

So, if I understood correctly, based on your experience: Those 8kw would be fully used as necessary to either only charge the batteries split between power to the load and power to charge the batteries. Correct?

If hypothetically my load is 6kw, the remaining 2kw available would be used to charge the battery, And if my load consumption lowers to 3kw, then 5kw would be used to charge the battery....Am I right in this assumption?
 
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Does anyone have any experience with the Sol Ark 12K and using a small generator to supplement the PV?
I have my Honda 65000 240v generator connected to the Sol Ark's Grid terminals and the configured to use Gen to Grid setting. Using the latest firmware from SA.

The generator charges the batteries fine except if I put a big load on and then it overloads the generator and trips the generator breaker (on the Honda).

In an attempt to correct this, I wanted to try generator peak shaving.
I put CTs on the two legs (arrow facing generator) and connected it to SA. I then configured this interface
View attachment 101563
To use grid peak shaving and set the value to 5500 Watts (not 9k). When I did this the inverter would only draw a few amps from the generator and did not seem to respect the peak shaving setting.

I called SA support and asked what the heck is the difference between Gen Limit Power and Grid Peak-shaving and the support person did not know either!! Apparently they are intended to do the same thing, but I'm not entirely clear on that..

Can someone with a similar setup explicate this?
Never tried this. Pretty interesting.

Just use the generator to blast amps into the batteries.

I have never needed it for peak shaving but interested in seeing if it works.

Every get definitive answer??
 
Does anyone have any experience with the Sol Ark 12K and using a small generator to supplement the PV?
I have my Honda 65000 240v generator connected to the Sol Ark's Grid terminals and the configured to use Gen to Grid setting. Using the latest firmware from SA.

The generator charges the batteries fine except if I put a big load on and then it overloads the generator and trips the generator breaker (on the Honda).

In an attempt to correct this, I wanted to try generator peak shaving.
I put CTs on the two legs (arrow facing generator) and connected it to SA. I then configured this interface
View attachment 101563
To use grid peak shaving and set the value to 5500 Watts (not 9k). When I did this the inverter would only draw a few amps from the generator and did not seem to respect the peak shaving setting.

I called SA support and asked what the heck is the difference between Gen Limit Power and Grid Peak-shaving and the support person did not know either!! Apparently they are intended to do the same thing, but I'm not entirely clear on that..

Can someone with a similar setup explicate this?

Hello All!

I just spoke with a rep from Sol-Ark. The person confirmed that indeed, Gen Limit Power uses the Inverter's internal sensors to limit the incoming power from the GEN INPUT. (I asked them to clarify this on a next revision of the manual)
1667585939351.png

You then configure the Charge under Batt Setup to use Gen Charge or Grid Charge (or both for grid tied inverters). The inverter will charge at whatever is configured. A = Amps in DC.
1667585731399.png

This will allow us to limit how much power can be used specifically to charge the battery leaving the rest of the allowed power setup in Gen Limit Power to be used to power the loads.

This way there is no need to use external CT sensors as the inverter would be using its internal sensors to measure incoming power and prevent overloading the generator.

Regarding Grid Peak Shaving, when using a generator on the grid input, as per manual, the external CT sensors are used to measure the incoming power and prevent overloading the generator. Since there is no "Grid Limit Power" setting, the external CT sensors allow the same "Gen Limit Power" functionality over the GRID Input as well as other features when inverter is GRID tied like Grid Sell or Limit Power to Home.

For people who have BIG generators like 15KW or so, using Grid Peak Shaving wouldn't be necessary as that would be enough to power the loads and charge batteries. Your only limiter would be the actual 67amp breakers on the GRID or LOAD breakers.

I hope this can be useful to all of you, especially to OP who is using a 6,500 watts generator. OP could use the GEN INPUT, set Limit Gen Power to desired 5,500 watts and then limit charging so as to consume perhaps 3,000 watts maximum, allowing an extra 2,200 watts to power loads at home and not overload the generator.

EDIT: If GRID Peak Shaving did not work and was only consuming a couple of watts, perhaps there could have been something wrong with one of the CT sensors.




I ended up disconnecting the CTs and just adjusting the “A” value on the charge screen on the battery setup. I had to set the “Grid Charge” option, which is a bit confusing because I’m not using the Grid.

I now understand that the reason for that is that you are using the GRID input instead of GEN input as those names refer to the Input Power Terminal being used. It can be possible to use both and when no PV power is present, you can either charge the batteries from GRID or GEN which can be useful for GRID tied inverters. For people who live in areas like the south-east coast or the Caribbean (my case) where hurricanes can be an issue. While there is still power available, it's possible to charge batteries from the GRID and preserve precious generator fuel.
 
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