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.