Sol-Ark no longer supporting gen shave

[Oldphile]

This sucks. I was planning to have 3 independent 15K connected to one generator and limit each to 4KW. The Sol-Ark was to reduce or stop battery charging if the loads + battery charging exceeded 4KW. Reversing the inverter to boost the generator above a 4KW load would have been a bonus but not necessary. According to Keith at SunSynk this is a viable function. I can't achieve this operation with an external charger. The Sol-Arks haven't had a software update in the last 14 months. Surprising that we are just hearing about this now.
@robby can you get clarification from Sol-Ark? Why can't we have peak shaving on the Gen Input.

 

[Cmiller]

This sucks. I was planning to have 3 independent 15K connected to one generator and limit each to 4KW. The Sol-Ark was to reduce or stop battery charging if the loads + battery charging exceeded 4KW. Reversing the inverter to boost the generator above a 4KW load would have been a bonus but not necessary. According to Keith at SunSynk this is a viable function. I can't achieve this operation with an external charger. The Sol-Arks haven't had a software update in the last 14 months. Surprising that we are just hearing about this now.
@robby can you get clarification from Sol-Ark? Why can't we have peak shaving on the Gen Input.

As I mentioned in the original post, using grid input and peak shaving through that is still an option. Although that severely limits the options then... especially if you have grid power and want to use a backup generator!

I did ask the tech (via email) for clarification on whether this only means we can't "gen assist" (to help feed loads higher than the gen's capability), or if it also means we can't limit gen draw other than adjusting gen charge amps. Although if it means no "gen assist" option, then I am curious if PV will be able to help feed loads while the gen is running... This is not a normal scenario, but I do see a number of installs where people run a gen for an off-grid woodworking shop etc., and the batteries get full before the end of the day, then using excess PV to feed loads is beneficial. (This type of scenario is probably mostly happening in the Amish communities, which is where I'm involved quite a bit.)

The more I roll this through my mind the more questions I have!

I also asked the tech why it works on Grid input, but not on gen input. I am still waiting for a reply, and will update once I hear back!

 

[Oldphile]

@Cmiller Thanks for questioning this. Once the generator is paralleled with the inverter there's no difference between grid input and gen input except for the use of external CTs. It doesn't make sense. I've submitted a tech support ticket. At the very least I need generator power limiting to stop charging the batteries even if the inverter can't reverse and provide generator assist.

 

[robby]

The issue with HF hybrid inverters is all power flows through the HV DC bus, with exception of AC input to AC output pass-through.

Problems comes into play during battery charging when an AC load shaving assist by inverter is required. The battery to HV DC converter must switch modes from charging batteries to sourcing power from batteries to supply the HV DC bus. This takes a little time to make the switchover in power flow direction. The large HV DC capacitor bank is supposed to absorb or source any power perturbations during the mode switchover, but it is limited on the total load it can support during the switchover time.

The problem SolArk is likely having is stability of the battery to HV DC converter causing potential damage to the unit under certain loading conditions.

This issue also effects excess PV power back surge power when external AC coupling of PV GT inverters is involved. SolArk recommends using Gen input reconfiguration for PV GT inverter AC coupling, so they have the instant ability to open the pass-through relay on gen port to dump the PV GT inverter if they get into trouble with too much excess power. Frequency shifting to reduce PV GT inverters output takes up to 2 seconds and is not fast enough when a large AC load is switched off, instantly creating an excess PV GT inverter power situation, when there is no grid present to dump excess PV power to.

LF hybrid inverters are inherently bi-directional and power flow can change from charging battery to sourcing AC output from battery instantly.

Yep that is what I also thought when I read the post.

You could get the Firmware rolled back in the past, I don't know if they still do it.
I suspect that they had a number of inverters go down while using gen shaving through the Gen port.
I can ask a friend of mine what is the situation and post back on it. If it is causing damage to the Inverter they probably won't roll back the Inverter.

Chargeverter in the Daytime is a bit risky if your running near the battery banks charge limits.
On a cloudy day you may be pumping in xxx amount of Amps from the Chargeverter and then the clouds break and the Inverter starts adding in it's full charging current on top of that.
You could keep messing with the Max charge, but who wants to do that!

 

[Cmiller]

Yep that is what I also thought when I read the post.

You could get the Firmware rolled back in the past, I don't know if they still do it.
I suspect that they had a number of inverters go down while using gen shaving through the Gen port.
I can ask a friend of mine what is the situation and post back on it. If it is causing damage to the Inverter they probably won't roll back the Inverter.

If that were the case, then why would tech support even suggest using grid peak shave with a generator...? Seems somehow directly related to the gen input terminals....

And furthermore, there are other inverters that can do gen shave! Take the Schneider XW for instance! I do realize that is a different inverter topology.

It's never good when features are rolled back.

Chargeverter in the Daytime is a bit risky if your running near the battery banks charge limits.
On a cloudy day you may be pumping in xxx amount of Amps from the Chargeverter and then the clouds break and the Inverter starts adding in it's full charging current on top of that.
You could keep messing with the Max charge, but who wants to do that!

Definitely a good point! Especially with a 15K, and the charge amps that they can push! And even grid were down but came back on while the chargeverter was charging, you could run into this as well.

 

[Oldphile]

If that were the case, then why would tech support even suggest using grid peak shave with a generator...? Seems somehow directly related to the gen input terminals....

Exactly. Sol-Ark should explain.

 

[Quattrohead]

Solark have always been very protective of their equipment so they must have seen a weakness that they are trying to mitigate.
EG4 are actively listening to customer feedback and developing the firmware so definitely keep making suggestions and asking questions, they are listening and improving the firmware, monitoring platform and documentation all the time.

 

[Oldphile]

Here's a good description of limiting generator power. I'm thinking that Generator Peak Shaving is a Sol-Ark myth. Just reducing battery charging to limit generator power will serve my needs.

 

[Cmiller]

That is a fantastic description! Thanks for that link!

Now to be clear, I honestly can't remember specifically ever seeing a Sol-Ark "assist" a gen to keep it from going into overload. I do know, however, that I have seen them reduce charging when using gen terminals, to keep gen load below that setpoint. I also know that one of our customers specifically noticed that, woth his gen feeding into gen terminals, sometimes the charging dynamically reduced to keep the draw below gen capacity, while other times it did not! I personally went on the job to troubleshoot, and noticed that most of the time when his well pump ran, the Sol-Ark (12K) would not show the proper draw that was on the gen. This was verified by shutting off the grn breaker and observing total load draw jump from ~300-500 watts up to 1,000-1,200 watts! It seemed as if the inverter was not correctly measuring power flowing through the Gen terminals.

As soon as we swotched to grid input, everything worked perfectly! Luckily, this job was an off-grid one. However, as was mentioned in the post you linked to, the gen terminals are to a certain degree controlled by the time-of-use settings as well. And that really, really sucks in a grid-tie setup with a backup generator!

I must say, I have been extremely dissappointed with Sol-Ark's lack of trying to address their obvious software issues! I love their inverters, but hate the glitches that they have!

Oh yes, and the fact that every time that I go on their website I see that "Entrepreneur Of The Year Award" plastered all over the website, when I'm trying to open tech support cases for glitches in software, doesn't help my overall opinion of the company!

It's not good for a company to brag, when they have product issues that they shrug off or are unwilling to address, or even admit to be issues!

 

[Cmiller]

Well, Sol-Ark emailed back now. It does sound like the only control over gen draw is to adjust the gen charge amps setting. From their wording, it could sound like maybe in the future this will be improved upon. They also did mention that the gen terminals are less sensitive than the grid terminals. They mentioned being sure to watch load balancing, and also setting the gen charge amps at a value that allows some "headroom" for house loads. I dare say that most times the potential house loads WILL be higher than the gen's power output rating. So..... this kind of upends any fine-tuned control over gen draw. The best thing to do then, is to plan to not be running loads when using a backup gen on the gen input!

Sol-Ark tech support also seems to think that it is perfectly logical to use an automatic transfer switch between grid and gen in order to use auto start, and still have Peak Shave (via "grid peak shave")........ and then when grid is down the auto start would start the gen. And you would need to enable peak shave when grid is off, but disable once grid is back on again..... And......... if grid comes back on while the gen is auto started the automatic transfer switch will switch to grid power, but the Sol-Ark will keep the gen running until the batteries reach the stop trigger........ Basically, forget about using the auto start relay when in a grid-tie scenario!

Here is a screenshot of the email from them:


Ugghhh..... This is all quite frustrating, to be honest!

 

[Oldphile]

And confusing. There are 2 possible operating modes and I'm not sure what Sol-Ark is describing.
1) When the power from the generator exceeds Gen Limit Power, battery charging is reduced. This is described in the manual.
Gen Limit Power: Sets the Sol-Ark limit to keep the power drawn from the “GEN” terminal below the
threshold. The inverter will reduce the charge power rate to the batteries if this value is reached.
2) When the power from the generator reaches the Gen Limit Power setting, the inverter will reduce battery charging and if necessary reverse and assist the generator in powering the loads.

I think Sol-Ark is describing the latter. Since the Gen Peak Shaving selection button has been removed from the Sol-Ark screens, I'm assuming that you can activate it from the Power View App, but as far as Sol-Ark is concerned it's an unsupported function.

BTW, I watched a SunSynk video yesterday where Keith described Gen Peak Shaving and the inverter screen had the Gen Peak Shave selection button.

 

[Cmiller]

And confusing. There are 2 possible operating modes and I'm not sure what Sol-Ark is describing.
1) When the power from the generator exceeds Gen Limit Power, battery charging is reduced. This is described in the manual.
Gen Limit Power: Sets the Sol-Ark limit to keep the power drawn from the “GEN” terminal below the
threshold. The inverter will reduce the charge power rate to the batteries if this value is reached.
2) When the power from the generator reaches the Gen Limit Power setting, the inverter will reduce battery charging and if necessary reverse and assist the generator in powering the loads.

I think Sol-Ark is describing the latter. Since the Gen Peak Shaving selection button has been removed from the Sol-Ark screens, I'm assuming that you can activate it from the Power View App, but as far as Sol-Ark is concerned it's an unsupported function.

I would agree that it sounds like the latter.

BTW, I watched a SunSynk video yesterday where Keith described Gen Peak Shaving and the inverter screen had the Gen Peak Shave selection button.

That is interesting. And also, I looked at our 12K at the shop, and it still has the Gen Peak Shave selection button/check box... Firmware is 6.2.2.2/1.4.3.F

 

[Oldphile]

I would agree that it sounds like the latter.

That is interesting. And also, I looked at our 12K at the shop, and it still has the Gen Peak Shave selection button/check box... Firmware is 6.2.2.2/1.4.3.F

That's the latest firmware. So, they removed the feature from the 15K, but not the 12K.

 

[Cmiller]

That's the latest firmware. So, they removed the feature from the 15K, but not the 12K.

And ironically enough, I have been noticing this issue of not adjusting according to that setting on the 12Ks specifically!

I like the Sol-Ark inverters, but they are going to have to address these issues, or they will have upset customers!

 

[robby]

I got some info from the head tech at Sol-Ark.
He said that this feature never really worked!
Evidently the GUI was constructed several years ago with that feature in it, but the Gen Port Shaving was never coded and implemented because of possible problems it would create.

He says that older firmware defaults to the Grid Shaving settings even if you put them in for Gen Shaving and select it.
The only reason why they removed this option from the GUI was because they recently cleaned up the GUI and decided to remove non operational parts of it. He did mention something about the Grid input and using an automatic transfer switch but did not go into details.

I am not going to get into any long arguments about this with anybody.
I was asked to find out what the story was and I am conveying what he said.
I don't have a 15K and I don't have a generator hooked up to my 12K, so I cannot test it.

The good news is that he also said that if anybody feels that it was working for them in the past, they can call and they will roll back their firmware to the older version.

 

[RCinFLA]

I got some info from the head tech at Sol-Ark.
He said that this feature never really worked!
Evidently the GUI was constructed several years ago with that feature in it, but the Gen Port Shaving was never coded and implemented because of possible problems it would create.

He says that older firmware defaults to the Grid Shaving settings even if you put them in for Gen Shaving and select it.
The only reason why they removed this option from the GUI was because they recently cleaned up the GUI and decided to remove non operational parts of it. He did mention something about the Grid input and using an automatic transfer switch but did not go into details.

I am not going to get into any long arguments about this with anybody.
I was asked to find out what the story was and I am conveying what he said.
I don't have a 15K and I don't have a generator hooked up to my 12K, so I cannot test it.

The good news is that he also said that if anybody feels that it was working for them in the past, they can call and they will roll back their firmware to the older version.

Someone knowing what they are talking about would never recommend an automatic transfer switch on single AC input to switch between gen and grid AC inputs. There must be enough gap time for inverter to detect open AC input and ensure release of pass-through relay before second AC source is presented to grid AC input port.

Also gen input is permanently configured to prevent backfeed, while grid input would have to be configured by user to prevent it when feeding from a generator connected to grid input port. This also effectively eliminates use of external CT transformer placed on grid mains lines allowing backfeed to main panel loads while preventing grid backfeed.

 

[robby]

Someone knowing what they are talking about would never recommend an automatic transfer switch on single AC input to switch between gen and grid AC inputs. There must be enough gap time for inverter to detect open AC input and ensure release of pass-through relay before second AC source is presented to grid AC input port.

Also gen input is permanently configured to prevent backfeed, while grid input would have to be configured by user to prevent it when feeding from a generator connected to grid input port. This also effectively eliminates use of external CT transformer placed on grid mains lines allowing backfeed to main panel loads while preventing grid backfeed.

As I said he mentioned something about a Transfer switch but did not go into details.
I was focused on the problem at hand.

 

[Cmiller]

I got some info from the head tech at Sol-Ark.
He said that this feature never really worked!
Evidently the GUI was constructed several years ago with that feature in it, but the Gen Port Shaving was never coded and implemented because of possible problems it would create.

He says that older firmware defaults to the Grid Shaving settings even if you put them in for Gen Shaving and select it.
The only reason why they removed this option from the GUI was because they recently cleaned up the GUI and decided to remove non operational parts of it. He did mention something about the Grid input and using an automatic transfer switch but did not go into details.

I am not going to get into any long arguments about this with anybody.
I was asked to find out what the story was and I am conveying what he said.
I don't have a 15K and I don't have a generator hooked up to my 12K, so I cannot test it.

The good news is that he also said that if anybody feels that it was working for them in the past, they can call and they will roll back their firmware to the older version.

Thanks @robby for asking into this! It at least helps clear the fog on what's what on the backend!

 

[DIYrich]

Someone knowing what they are talking about would never recommend an automatic transfer switch on single AC input to switch between gen and grid AC inputs.

If you have a sol-ark for backup purposes, you should have enough batteries to have time to manually flip the switch. If the grid is down long enough to need the generator, you may want to stay disconnected to give the grid time to stabilize as they continue to fix it.

 

[wheisenburg]

LF hybrid inverters are inherently bi-directional and power flow can change from charging battery to sourcing AC output from battery instantly.

Good to know this. I have a pair of Schneider XW Pros with 9000 Watts of PV that is AC coupled. I only have 3 batteries at 100 amps each. Normally, I am grid tied, but I still worry about the ability of the system to handle all this PV when off-grid. I have come up with a scheme for PV Shedding when SOC is high. I plan to use the relay outputs to drive the logic for now. Maybe I will come up with something better eventually.