Sol-Ark 15K Generator Transfer Time

[Tulex]

I had a Generac 10k LP generator attached to my house before installing solar. Removed it during full remodel of the house.

I'm going back and forth between AC coupling and the generator, as I don't see how to have both. One of the considerations is transfer time for the generator. In it's original configuration before solar, it took about a minute for the generator to provide power. So my question is, does the Sol-Ark start the generator and wait for power before it switches over?

 

[sunshine_eggo]

https://www.sol-ark.com/wp-content/uploads/5K-2P-N_Manual.pdf

 

[Tulex]

That's for the 5K

I did find the same in the 15K manual, didn't see it before as it's under off grid setup.

 

[Tulex]

So to answer my own question....

Got ahold of Sol-Ark. They said it works the same whether grid tied or not in that, the switch over is seamless, just like batteries.
The only difference is, if grid tied, as soon as grid comes back, generator disconnects.

 

[DIYrich]

If you already have an ATS, then connect the Sol-Ark after the ATS, and wire the genstart from the Sol-Ark.
When grid goes down, the Sol-Ark will detect grid down, and island the Gen Input port. When batteries reach the set point, it will send a Gen Start, and then ATS will switch to the Generator. The sol-ark will know if the grid or generator is connected (grid is stiff, generator is not).

 

[Tulex]

If you already have an ATS, then connect the Sol-Ark after the ATS, and wire the genstart from the Sol-Ark.
When grid goes down, the Sol-Ark will detect grid down, and island the Gen Input port. When batteries reach the set point, it will send a Gen Start, and then ATS will switch to the Generator. The sol-ark will know if the grid or generator is connected (grid is stiff, generator is not).

Not sure why I would do that and not just run it right to my inverter?
The Generac was installed with an ATS. I guess that's what you would call it. A panel box with the electronics and switch to disconnect the main panel and move infeed to generator. Fed from the panel box with critical loads in the ATS box.
I took that all down during the remodel. Now, grid goes right into the 15K, main and only panel box is fed from the 15K.
If the 15K can fully manage the generator, why add another component?

 

[DIYrich]

If the 15K can fully manage the generator, why add another component?

Generator can connect on the grid connection or smart load. If you already have the ATS, then use it to keep the smart load available for something else.

 

[RCinFLA]

Hybrid grid interactive inverter with dual AC inputs have two pass-through relays, one for each AC input, but only one is used at a time.

Inverter must gradually align its sync to AC input. Abrupt AC phase shift is not allowed due to possibility of AC motor loads that will create forward or reverse current surges if AC phasing is abruptly changed. With two AC inputs the process of jumping from one to the other input source is described below.

For a grid or generator AC inputs, usually grid is the priority (preferred) input.

Inverter is running in parallel with whatever AC source is present. You can start up inverter from a standby mode to save inverter idle overhead power but this has a greater transfer glitch time to activate inverter after an AC input dropout.

So lets start example running in UPS mode with grid present and inverter running in parallel with grid.

1) Grid drops out.

2) Inverter, running in parallel, momentarily tries to power collapsed grid but getting an overload surge, releases pass-through relay grid connection. Grid backfeed sensing is not fast enough to prevent this. This momentary overload creates a slight AC voltage dip in AC output for less than 8 millisecs (half AC cycle max time) and most appliances ride through it without any notice of it. The glitch time varies depending where in the AC cycle the grid collapsed and how abrupt it collapsed. Often the grid voltage sags before it drops out causing inverter to release early resulting in little to no glitch in AC output.

3) Battery powered inverter now supplying AC output loads. Inverter is now its own master and gradually moves to its center frequency and AC voltage. (should be close to grid frequency and voltage to 240/120vac even if grid was higher or lower when it was present).

4) Inverter auto-start fires up generator, with an allotted warmup time.

5) After allotted generator warmup time, inverter senses AC voltage on Gen AC input. Inverter begins to slowly align it phasing and voltage to match that of generator. This may take 2-60 seconds depending on generator frequency relative to initial inverter frequency. Battery power is being used to support loads during this crossover.

6) Once inverter syncs to generator it closes pass-through relay allowing power to be drawn from generator. You may have a generator AC input current limit set up which limits how much current can be drawn from generator. AC output above this limit is supplemented by inverter battery power. Charging power has second priority to AC output loads so charging will be backed down to stay within limits of AC input current setting.

Sometime later grid shows back up again.

7) Inverter senses AC voltage present on Grid AC input which is set to priority (preferred) AC input.

8) Inverter releases from generator and picks up AC output load from inverter/battery power.

9) Inverter begins to resync to grid AC input. This takes less time because grid has a much tighter frequency limit.

10 Once sync is achieved, pass-through relay to grid AC input is closed, allowing power to be accepted from grid.

11) Inverter allows a no-load running cool down time before shutting down generator.

 

[Tulex]

Yes, that sounds like a longer version of what Sol-Ark said.