Sol-Ark fails to turn on generator causing power outage

[tve]

This morning the grid went out and once the batteries ran down power went out to the house. Except, the Sol-Ark was supposed to turn on the generator but it didn't!

I'm trying to understand why (and will have to run some tests once things are back to more normal). Something that caught my eye is the following statement in the latest Sol-Ark manual (July 13, 2023) https://www.sol-ark.com/wp-content/uploads/15K-2P_Manual.pdf in the section "2.6 Automatic Generator Charge":

If “Time of Use” (“TOU”) is enabled, “? Charge” must be checked on desired time intervals. Otherwise, the generator won’t automatically start even if the Start V or Start % condition has been met.​

But if I check that "charge" box it will charge the batteries from the grid and I don't want that (except during a 1h time-frame just before the peak power period)! It makes no sense to me that the Sol-Ark wouldn't turn on the generator when the batteries reach a critical low level. Am I confused or missing something?

To get through the outage I had to manually turn the generator on and check "Force gen".

Set-up: Sol-Ark 15k, 12kW solar, 20kWh battery connected via CAN, 15kW genset connected to gen input. Gen start set to 10% SoC, gen max power set to 8kW, gen bat charge amps set to 100A.
References: the above statement appears in section 2.6 and again in section 3.3 under the TOU stuff

 

[Oldphile]

What do you have checked here?

 

[tve]

I believe these are the relevant screens (apologies for the angle, I'm having a hard time avoiding glare):

 

[Oldphile]

You don't have Grid charge checked, so it shouldn't charge from the grid. Hopefully someone else will jump in here.

 

[tve]

I didn't ask about charging from the grid. I asked about charging from the generator when the grid is out and the batteries are below critical SoC.

 

[Oldphile]

But if I check that "charge" box it will charge the batteries from the grid and I don't want that

I'm confused.

 

[tve]

I see, you're saying that I should check "charge" in all the TOU periods but keep "grid charge" unchecked?

So I currently have TOU "charge" checked for the 3rd TOU period which goes from 2:30pm to 4pm with a 75% SoC set. This causes the battery to be charged up to 75% from the grid before the peak period (4pm-9pm). This works. Thus the TOU "charge" setting overrides the general "grid charge" setting on the battery>charge tab.

I want the gen to come on if the batteries are about to be empty and the grid is dead. I don't want to have to enable charging the batteries from the grid at all times to accomplish that, that would completely defeat the TOU settings.

 

[Oldphile]

Yes, you need to check "charge" for all time slots that you would require Gen charge. Your Start % at 10% is really low. This number needs to be higher than your Discharge Shutdown %.

 

[tve]

The problem with what you're suggesting is that when "TOU charge" is checked then the "batt %" field refers to what level the batteries should be charged to whereas with "TOU charge" it refers to the what level the batteries may be discharged in order not to consume grid power. So I would completely loose the functionality to avoid using grid power when solar is insufficient.

Re "Your Start % at 10% is really low. This number needs to be higher than your Discharge Shutdown %." -- my discharge shutdown is set to 5%, so start% is higher than discharge-shutdown%.

 

[Oldphile]

The problem with what you're suggesting is that when "TOU charge" is checked then the "batt %" field refers to what level the batteries should be charged to whereas with "TOU charge" it refers to the what level the batteries may be discharged in order not to consume grid power. So I would completely loose the functionality to avoid using grid power when solar is insufficient.

Re "Your Start % at 10% is really low. This number needs to be higher than your Discharge Shutdown %." -- my discharge shutdown is set to 5%, so start% is higher than discharge-shutdown%.

Yes, I think it's an either or situation. You use the TOU to charge the batteries to a specified SOC% (charge checked) or discharge the batteries to SOC% (charge not checked). I think you also have to select "Sell" in order to discharge the batteries. Each time slot can be one or the other.

10% start, 5% shutdown, okay.

If anyone has a better understanding please jump in.

 

[tve]

"Sell" is not required to discharge the batteries. That is handled by (section 3.3 TOU) "Energy Priority: 1. Solar PV Power | 2. Batteries (down to programmed discharge V or %) | 3. Grid Power | 4. Generator", i.e. it will use battery power before grid power (until batteries reach the Batt% value).

There is a post by Carlos that details how it works. I have two issues:
1. Forget about charging batteries for a second, when the inverter is about to shut down the power to the loads it should first try to power up the generator to power the loads. "Generator" is listed as 4th item in that energy priority list after all. (Really, once the generator-start battery percentage is reached the generator should turn on to power the loads if the grid is down, period.)
2. The quadruple-overloading of the "Batt% in the TOU settings" (grid on/off, grid/gen) is crazy and make it impossible to configure some scenarios that would otherwise be easy. It also makes it very difficult to understand the configuration (without Carlos' post it's actually impossible).

NB: thanks for your replies, they're appreciated!

 

[Oldphile]

The post by Carlos gave me new insight into TOU. Thankyou.

 

[robby]

From my understanding of it during a power outage the TOU is no longer in play.
The PV and batteries will power the load until you reach the SOC level in the menu shown in post#2. And btw 10% is way to low, something like 40% makes more sense.
Then the generator will turn on and charge the batteries and power the house until the Grid comes back or the batteries reach 100%.

 

[DIYrich]

Can you post a clear picture of your TOU and Smart load tabs?

 

[#40Fan]

I believe these are the relevant screens (apologies for the angle, I'm having a hard time avoiding glare):

Throw a towel over your head and the device to get rid of the glare. That'll help get clearer pics.

 

[Ben2022]

Did you ever figure this problem out? I had the EXACT same situation yesterday. No Grid power, Batteries hit SOC cutoff (30% in my case), and Sol-Ark did NOT start the generator.

 

[DIYrich]

Did you ever figure this problem out? I had the EXACT same situation yesterday. No Grid power, Batteries hit SOC cutoff (30% in my case), and Sol-Ark did NOT start the generator.

TOU only applies to Grid. When Grid is down, TOU is ignored.

On the Batt screen, charge tab, check "gen charge", and start voltage or soc should be above "low batt" on the Discharge tab.

Make sure you told the Sol-ark which connection has the generator. If on Grid input, then in the smart load tab, check the box "use gen input as load output" just to be sure it doesn't look for the generator there.

Check generator control by "gen force" on the charge tab.

 

[Ben2022]

TOU only applies to Grid. When Grid is down, TOU is ignored.

On the Batt screen, charge tab, check "gen charge", and start voltage or soc should be above "low batt" on the Discharge tab.

Make sure you told the Sol-ark which connection has the generator. If on Grid input, then in the smart load tab, check the box "use gen input as load output" just to be sure it doesn't look for the generator there.

Check generator control by "gen force" on the charge tab.

Awesome. I know the force gen works and my generator will jog as appropriate. I made the adjustment as shown below.

I’m assuming the Gen charge will ONLY apply if grid is not present as OP and I both intend.

Thanks for the info

 

[DIYrich]

I’m assuming the Gen charge will ONLY apply if grid is not present as OP and I both intend.

correct. Just to be sure, set Grid start to 32, and gen start at 30. Then it won't hit gen start unless Grid is down.

 

[DIYrich]

Note: AC coupled on load side is not recommended. Put the AC PV into the smart load port.

 

[Ben2022]

Note: AC coupled on load side is not recommended. Put the AC PV into the smart load port.

I know, it’s only temporary. My AC panels are on my house. The entire rest of the system is in a detached garage including the DC panels. I’m going to run the wiring directly over to the Gen port on the Sol Ark I just haven’t been able to do it yet.

 

[Oldphile]

TOU only applies to Grid. When Grid is down, TOU is ignored.

That's not what @Carlos_Sol-Ark said in this post. He specifically describes TOU while off grid. The Power setting is ignored while off grid, but TOU can be used to select if Gen Charge can be active in any time slot. % in TOU sets the SOC end of charging.

If batteries discharge down to Start% in Batt Setup and Charge is checked in TOU then the generator should start and charge the batteries until batteries reach SOC % set in TOU.

 

[LydMekk]

Oldphile is correct.
TOU override are active both in grid connected and in off-grid.
If you disable the TOU then the inverters standard set values apply.

 

[Cmiller]

@Carlos_Sol-Ark read through this thread please..... This is what I was talking about when I mentioned a SEPARATE gen start menu in my PM to you! I have literally been bringing this issue up to the tech support guys for probably 4 years now.....

What does it take to be heard on issues like these, and see results in terms of changes?

To OP and anyone else looking at this thread.... TOU will most definitely limit the gen charge exactly like it does the grid charge. Even when using gen terminals specifically! TOU limits ALL AC CHARGING!

This should not be! Gen terminals, gen auto start and gen input should be 100% isolated from grid, as far as how and when it is used!

A workaround is to turn on gen force and leave it on at all times, then use a Victron BMV-712 battery monitor and program it's relay to start and stop the gen. You will also want to then have a relay with it's coil activated by grid, and with the gen start signal run through the contacts, so that when grid comes back on, the gen start signal is broken.

Another note, if you don't have TOU enabled, gen start will work when grid goes down. But...... when grid comes back on the gen won't shut down until the stop parameter is reached. The stop parameter, by the way, is not user accessible.... it is built-into the backend to stop at ~95%.....

 

[Oldphile]

Another note, if you don't have TOU enabled, gen start will work when grid goes down. But...... when grid comes back on the gen won't shut down until the stop parameter is reached. The stop parameter, by the way, is not user accessible.... it is built-into the backend to stop at ~95%.....

So, the Sol-Ark disconnects from the generator, but leaves the generator running OR it charges the battery to 95% before connecting to the grid. Generator running after the grid returns is certainly undesirable.

I agree with your point. Off grid TOU should be separated from On grid. Maybe this is inherently impossible. I don't know, I haven't written code since college 50+ years ago. Both SunSynk and Deye have this same shortfall.