Generac 7500 watt generator and Growatt 6KW Inverter

[Jonathan3900]

I have asked this question a few times and have received multiple answers. So, I will be more specific this time.

Here is what I have.

Generac 7500watt Propane Generator
Growatt 6kw Inverter
(2) Big Battery Husky 48v batteries
(8) 350watt Solar panels

What I am trying to do.

I want the Generac to come on when the batteries go low. I know that the settings on the inverter "should" turn the generator off and on. Well, they don't. I had Generac come out today, and the issue is that the generator needs a utility power source to charge the battery and the start-stop to work.

Or if this above won't work, does anyone know how to do either of these?

~ Run the "exercise" once a day for an hour instead of weekly for 15 minutes
~ Have a solution where I could, once a day, turn the generator on/off remotely for an hour. (not exactly what I want to do, but I don't have many options)

Can anyone help with this?

Thank you,

Jonathan

 

[timselectric]

I have asked this question a few times and have received multiple answers. So, I will be more specific this time.

Here is what I have.

Generac 7500watt Propane Generator
Growatt 6kw Inverter
(2) Big Battery Husky 48v batteries
(8) 350watt Solar panels

What I am trying to do.

I want the Generac to come on when the batteries go low. I know that the settings on the inverter "should" turn the generator off and on. Well, they don't. I had Generac come out today, and the issue is that the generator needs a utility power source to charge the battery and the start-stop to work.

Or if this above won't work, does anyone know how to do either of these?

~ Run the "exercise" once a day for an hour instead of weekly for 15 minutes
~ Have a solution where I could, once a day, turn the generator on/off remotely for an hour. (not exactly what I want to do, but I don't have many options)

Can anyone help with this?

Thank you,

Jonathan

You should be able to provide the "utility source" from the inverter output loads panel.

 

[Jonathan3900]

You should be able to provide the "utility source" from the inverter output loads panel.

Can you explain? Are you saying to come out of the generator (from the panel), and over to the Generac?

 

[Supervstech]

I have asked this question a few times and have received multiple answers. So, I will be more specific this time.

Here is what I have.

Generac 7500watt Propane Generator
Growatt 6kw Inverter
(2) Big Battery Husky 48v batteries
(8) 350watt Solar panels

What I am trying to do.

I want the Generac to come on when the batteries go low. I know that the settings on the inverter "should" turn the generator off and on. Well, they don't. I had Generac come out today, and the issue is that the generator needs a utility power source to charge the battery and the start-stop to work.

Or if this above won't work, does anyone know how to do either of these?

~ Run the "exercise" once a day for an hour instead of weekly for 15 minutes
~ Have a solution where I could, once a day, turn the generator on/off remotely for an hour. (not exactly what I want to do, but I don't have many options)

Can anyone help with this?

Thank you,

Jonathan

Do you have a transfer switch?

If the inverter output is fed to the generator line voltage transfer switch, then when the inverter switches off due to low batteries, the generator should start up.

If there is no transfer switch, and you only have a generator autostart function, then you need a trickle charger connected to inverter output to keep the battery on the generator charged.

 

[timselectric]

Can you explain? Are you saying to come out of the generator (from the panel), and over to the Generac?

Assuming that you are using the generator as a backup for your solar system.
The inverter is treated as the grid source.

 

[Dave911]

I want the Generac to come on when the batteries go low. I know that the settings on the inverter "should" turn the generator off and on. Well, they don't. I had Generac come out today, and the issue is that the generator needs a utility power source to charge the battery and the start-stop to work.

Are the contacts on the Growatt inverter closing when the battery bank runs low in order to start the generator?

How is the Growatt wired to the generator?

Pictures of your generator wiring diagram showing the run/stop controls would be helpful.

 

[Jonathan3900]

Are the contacts on the Growatt inverter closing when the battery bank runs low in order to start the generator?

How is the Growatt wired to the generator?

Pictures of your generator wiring diagram showing the run/stop controls would be helpful.

I am returning to the cabin this weekend and will get these for you. Thank you.

 

[Jonathan3900]

Do you have a transfer switch?

If the inverter output is fed to the generator line voltage transfer switch, then when the inverter switches off due to low batteries, the generator should start up.

If there is no transfer switch, and you only have a generator autostart function, then you need a trickle charger connected to inverter output to keep the battery on the generator charged.

We do have the transfer switch but aren't using it.

We think the generator does have this option to auto-start. At least, that is what the salesperson said.

I sent your reply to my electrician and am waiting to hear back from him.

Thank you very much. I will let you know once he replies.

Jonathan

 

[740GLE]

Side note: Be mindful of the duty cycle of that Generac when charging up your bank.

I personally wouldn’t want to load up the generator beyond 50% is name plate. They aren’t designed for constant heavy demand. The harder you push the generator with constant demand the shorter it’s life will be.

End side note.

 

[50ShadesOfDirt]

If this is a standby Generac, it has to be installed correctly, per the model's site installation manual. Usually, the authorized dealer technician does this for you, and that would've included running a power circuit back out to the generator to supply it's internal battery charger. Standby Generacs don't charge their internal batteries when the generator is running, unlike many portable generators. Some folks handle this with an external trickle charger connected to the battery. Just remember that, with Generac, any deviation from their site installation manual could be cause to not honor the warranty ... this usually includes trying to run a Generac standby generator in an "off-grid" scenario, which they don't allow (but if you go self-supporting, then you can do what you want, there is just no warranty).

Next, you'll probably need the 2-wire start kit for it (a bag with some additional wires for your model). Any authorized generac dealer will sell you this kit. There should be instructions for installing these wires, and possibly adjust some settings in the controller. Then, the generac is placed into auto mode, and it is ready to autostart.

Finally, you'll wire from your "autostart" device back to the Generac, per the wiring diagram for your inverter. Usually, the inverter folks supply the wiring diagram.

Hope this helps ...

 

[Jonathan3900]

Side note: Be mindful of the duty cycle of that Generac when charging up your bank.

I personally wouldn’t want to load up the generator beyond 50% is name plate. They aren’t designed for constant heavy demand. The harder you push the generator with constant demand the shorter it’s life will be.

End side note.

I appreciate your help. I appreciate it.

 

[Jonathan3900]

If this is a standby Generac, it has to be installed correctly, per the model's site installation manual. Usually, the authorized dealer technician does this for you, and that would've included running a power circuit back out to the generator to supply it's internal battery charger. Standby Generacs don't charge their internal batteries when the generator is running, unlike many portable generators. Some folks handle this with an external trickle charger connected to the battery. Just remember that, with Generac, any deviation from their site installation manual could be cause to not honor the warranty ... this usually includes trying to run a Generac standby generator in an "off-grid" scenario, which they don't allow (but if you go self-supporting, then you can do what you want, there is just no warranty).

Next, you'll probably need the 2-wire start kit for it (a bag with some additional wires for your model). Any authorized generac dealer will sell you this kit. There should be instructions for installing these wires, and possibly adjust some settings in the controller. Then, the generac is placed into auto mode, and it is ready to autostart.

Finally, you'll wire from your "autostart" device back to the Generac, per the wiring diagram for your inverter. Usually, the inverter folks supply the wiring diagram.

Hope this helps ...

Thank you for your help. I have given my electrician this thread so he can figure out what is needed.

 

[Jonathan3900]

This is my electrician and the Generac person's conversation. Any thoughts/help?

Hello Jon,
I read through the forum and it looks like we are sort of grappling with 2 different scenarios here.

Scenario 1 is to run the generator when the batteries get low. This is virtually impossible, since ideally the inverter would start the generator on low batteries, but the generac's control system will NOT allow this to happen, since technically the output of the inverter would still be telling the generator that it has line power.

Scenario 2 is to run the generator when the inverter dies from low batteries, which is of course an option, but still problematic. Once the generator kicks on, it will power the inverter back on, which will in turn trigger the generator to go off since it will see the output of the inverter and think power came back on. This will continue in a death loop until the inverter batteries are back up to charge, or until the generator battery dies from exhaustion. Also, this step means charging the inverter batteries from zero, which is not really a good thing to have to do. We want power before then.

A trickle charger for the battery on the generator is a simple solution, but this generator needs to see utility power before it does anything anyway, and that would make the trickle charger unnecessary.

The generator is 2 wire start capable already, so that is not the problem. The problem is that it will not allow 2 wire start UNTIL it sees utility power cut out, i.e. the inverter batteries have died.

The Generac tech said that you could do a relay system to the auto transfer switch to shut on/off the inverter power(only to the generator), which would trick the generator into actually starting BEFORE the inverter dies. This option is theoretically doable, but you would need a 2 wire non-automatic transfer switch to pull it off. Also, I am NOT convinced the output control wires from the inverter are sized correctly to achieve this feat. Also, it is REALLY going down a rabbit hole of potential device compatibility. IF anyone knows of a compatible 2 wire controlled transfer switch that will work with the output controls on the GroWatt inverter, that would be the first place to start.

Also, talking to the Generac Rep, it sounds like ALL their generators are made to be hooked to the grid in order to function properly as auxiliary power units. This would mean that MOST of the back up generators on the market would probably equally be geared to work in the same way, so the chances are high we would end up the same way even with another brand. Does Grow Watt make a backup auxiliary generator for this application, or did they just go all in on solar as the final solution? Seems pretty optimistic.

 

[Dave911]

This is my electrician and the Generac person's conversation. Any thoughts/help?

Hello Jon,
I read through the forum and it looks like we are sort of grappling with 2 different scenarios here.

Scenario 1 is to run the generator when the batteries get low. This is virtually impossible, since ideally the inverter would start the generator on low batteries, but the generac's control system will NOT allow this to happen, since technically the output of the inverter would still be telling the generator that it has line power.

Scenario 2 is to run the generator when the inverter dies from low batteries, which is of course an option, but still problematic. Once the generator kicks on, it will power the inverter back on, which will in turn trigger the generator to go off since it will see the output of the inverter and think power came back on. This will continue in a death loop until the inverter batteries are back up to charge, or until the generator battery dies from exhaustion. Also, this step means charging the inverter batteries from zero, which is not really a good thing to have to do. We want power before then.

A trickle charger for the battery on the generator is a simple solution, but this generator needs to see utility power before it does anything anyway, and that would make the trickle charger unnecessary.

The generator is 2 wire start capable already, so that is not the problem. The problem is that it will not allow 2 wire start UNTIL it sees utility power cut out, i.e. the inverter batteries have died.

The Generac tech said that you could do a relay system to the auto transfer switch to shut on/off the inverter power(only to the generator), which would trick the generator into actually starting BEFORE the inverter dies. This option is theoretically doable, but you would need a 2 wire non-automatic transfer switch to pull it off. Also, I am NOT convinced the output control wires from the inverter are sized correctly to achieve this feat. Also, it is REALLY going down a rabbit hole of potential device compatibility. IF anyone knows of a compatible 2 wire controlled transfer switch that will work with the output controls on the GroWatt inverter, that would be the first place to start.

Also, talking to the Generac Rep, it sounds like ALL their generators are made to be hooked to the grid in order to function properly as auxiliary power units. This would mean that MOST of the back up generators on the market would probably equally be geared to work in the same way, so the chances are high we would end up the same way even with another brand. Does Grow Watt make a backup auxiliary generator for this application, or did they just go all in on solar as the final solution? Seems pretty optimistic.

I read all of this and I know that Generac generators can be setup to run without a grid power connection and be started remotely with a contact closure.

The reason I know this is that the guy who lived next to me is Amish (no grid power) and he had a Generac generator that ran off propane that he started remote from inside his house. The generator was remote, behind his store. About 200 ft from his house.
So it can be done. Also, I know that he did not set it up. He wasn't very good with electricity.

He ran his Generac everyday since that was all they had for power. It lasted for years, probably running 6+ hours per day.
It finally blew and now they have another generator in a small building. Its natural gas powered since they ran a line down our road 5 years ago.
Don't ask me about the logic behind this. I can't figure it out and I have lived here for 27 years.

I thought you were entirely off grid? Is that correct.

 

[timselectric]

This is my electrician and the Generac person's conversation. Any thoughts/help?

Hello Jon,
I read through the forum and it looks like we are sort of grappling with 2 different scenarios here.

Scenario 1 is to run the generator when the batteries get low. This is virtually impossible, since ideally the inverter would start the generator on low batteries, but the generac's control system will NOT allow this to happen, since technically the output of the inverter would still be telling the generator that it has line power.

Scenario 2 is to run the generator when the inverter dies from low batteries, which is of course an option, but still problematic. Once the generator kicks on, it will power the inverter back on, which will in turn trigger the generator to go off since it will see the output of the inverter and think power came back on. This will continue in a death loop until the inverter batteries are back up to charge, or until the generator battery dies from exhaustion. Also, this step means charging the inverter batteries from zero, which is not really a good thing to have to do. We want power before then.

A trickle charger for the battery on the generator is a simple solution, but this generator needs to see utility power before it does anything anyway, and that would make the trickle charger unnecessary.

The generator is 2 wire start capable already, so that is not the problem. The problem is that it will not allow 2 wire start UNTIL it sees utility power cut out, i.e. the inverter batteries have died.

The Generac tech said that you could do a relay system to the auto transfer switch to shut on/off the inverter power(only to the generator), which would trick the generator into actually starting BEFORE the inverter dies. This option is theoretically doable, but you would need a 2 wire non-automatic transfer switch to pull it off. Also, I am NOT convinced the output control wires from the inverter are sized correctly to achieve this feat. Also, it is REALLY going down a rabbit hole of potential device compatibility. IF anyone knows of a compatible 2 wire controlled transfer switch that will work with the output controls on the GroWatt inverter, that would be the first place to start.

Also, talking to the Generac Rep, it sounds like ALL their generators are made to be hooked to the grid in order to function properly as auxiliary power units. This would mean that MOST of the back up generators on the market would probably equally be geared to work in the same way, so the chances are high we would end up the same way even with another brand. Does Grow Watt make a backup auxiliary generator for this application, or did they just go all in on solar as the final solution? Seems pretty optimistic.

It isn't that complicated. We just need a little bit more information.
1. How does the generator sense grid power?
2. Are you trying to use the Generac transfer switch?

Personally I wouldn't bother with the transfer switch. As it's not needed for this situation.

 

[50ShadesOfDirt]

I'm off-grid, and when I ran my Generac 22KW standby unit (self-supported btw, as standby's are not to be used off-grid), it was as easy as the steps listed in my previous post. My only problem was that the Generac lasted only about 2000 hours, and was so complex to repair that I couldn't keep it running, at least not without the super-secret field service manual (only authorized dealer techs have this manual), which I could never obtain.

I *did not* have an ATS in the middle, and the generac did exactly what it was supposed to do ... inverter (magnum) saw battery power getting down to a set point value and signaled the gen to start, and gen started. Inverter sensed gen power coming in, and did the right thing with that power, charging the batteries and also letting power pass-thru to house. When batteries were good, inverter signaled gen to stop, and gen did so. I did run a circuit out to Generac, to power it's internal battery charger (and prevent further "errors" about no power to battery charger), but I then disabled the battery charger. The trickle charger just worked ... never had battery issues again. Still don't, even with other gens in use ...

Most of what is being described (from electrician's and Generac's side) sounds like ATS issues ... can't help with that, as ATS is another layer of 'who's on first ..."

BTW, the trickle charger is fallback insurance to "never having a dead battery" for whatever reason. Before I implemented it, I'd find the scenarios where the battery managed to get to a dead state. After the trickle charger, those supposedly never-occuring dead-state battery scenarios finally ended (the problems moved elsewhere).

OP didn't list an ATS, a key operational point if it is there ... if there is an ATS, then you might indeed need the electrician (an auth'd Generac installer?) and Generac to sort things out. But then, why is there an inverter in the mix, as standby gen's have a sweet-spot of playing in an on-grid scenario with no inverter. Grid power goes out, gen comes on, and ATS is the traffic cop ...

So, if an ATS is in there ... you must find an example of a design where all the elements you really have are lined up and working together (grid, ats, inverter/battery-bank, gen). Then, get from all the elements you've got to what that design shows as needing ...

I'll go out on a limb and say that this design wasn't really there in the first place? If so, that's step one. If there was a design, the designer needs to get involved ...

 

[Dave911]

In the standby power industry, or prime generator industry, Generac doesn't have a great reputation.
Google Generjunk and Genercrap. You will see what I am talking about.

I don't have a Generac. The one next door grenaded when it was used as a primary generator, but it took a few years of running 6+ hours per day. I'm guessing, but I suppose they got 4-5000 hours out of it. That doesn't seem horrible to me. That probably worked out to be about $1 per hour of running time, or something close. A good 1800 rpm diesel generator should last a lot longer but it is also +3x the price.

But the Onan and Caterpillar guys really look down on Generac. I didn't realize that until I looked for help repairing my Onan generator on the web.

 

[Supervstech]

In the standby power industry, or prime generator industry, Generac doesn't have a great reputation.
Google Generjunk and Genercrap. You will see what I am talking about.

I don't have a Generac. The one next door grenaded when it was used as a primary generator, but it took a few years of running 6+ hours per day. I'm guessing, but I suppose they got 4-5000 hours out of it. That doesn't seem horrible to me. That probably worked out to be about $1 per hour of running time, or something close. A good 1800 rpm diesel generator should last a lot longer but it is also +3x the price.

But the Onan and Caterpillar guys really look down on Generac. I didn't realize that until I looked for help repairing my Onan generator on the web.

I stole the 5kw onan out of my dads 72 motorhome before he scrapoed it, i has gotten me through several ice storms, and has never needed more than a little piston cleaning...

Yeah... the manual says to pull the heads off and scrape off the piston for service... flathead under head cam engines may be inefficient... but i havnt done any service besides oil change to this thing in DECADES... i doubt a generac can claim the same...

I service hvac-E and genwrator maintenance is one of my chores...

One customer has a 45kW eaton with a generac powerplant...

Yeah... crap.

 

[magnet creek]

This is my electrician and the Generac person's conversation. Any thoughts/help?

Hello Jon,
I read through the forum and it looks like we are sort of grappling with 2 different scenarios here.

Scenario 1 is to run the generator when the batteries get low. This is virtually impossible, since ideally the inverter would start the generator on low batteries, but the generac's control system will NOT allow this to happen, since technically the output of the inverter would still be telling the generator that it has line power.

Scenario 2 is to run the generator when the inverter dies from low batteries, which is of course an option, but still problematic. Once the generator kicks on, it will power the inverter back on, which will in turn trigger the generator to go off since it will see the output of the inverter and think power came back on. This will continue in a death loop until the inverter batteries are back up to charge, or until the generator battery dies from exhaustion. Also, this step means charging the inverter batteries from zero, which is not really a good thing to have to do. We want power before then.

A trickle charger for the battery on the generator is a simple solution, but this generator needs to see utility power before it does anything anyway, and that would make the trickle charger unnecessary.

The generator is 2 wire start capable already, so that is not the problem. The problem is that it will not allow 2 wire start UNTIL it sees utility power cut out, i.e. the inverter batteries have died.

The Generac tech said that you could do a relay system to the auto transfer switch to shut on/off the inverter power(only to the generator), which would trick the generator into actually starting BEFORE the inverter dies. This option is theoretically doable, but you would need a 2 wire non-automatic transfer switch to pull it off. Also, I am NOT convinced the output control wires from the inverter are sized correctly to achieve this feat. Also, it is REALLY going down a rabbit hole of potential device compatibility. IF anyone knows of a compatible 2 wire controlled transfer switch that will work with the output controls on the GroWatt inverter, that would be the first place to start.

Also, talking to the Generac Rep, it sounds like ALL their generators are made to be hooked to the grid in order to function properly as auxiliary power units. This would mean that MOST of the back up generators on the market would probably equally be geared to work in the same way, so the chances are high we would end up the same way even with another brand. Does Grow Watt make a backup auxiliary generator for this application, or did they just go all in on solar as the final solution? Seems pretty optimistic.

Hi Jon, I am trying to do exactly the same as what you are trying to do, so curious what you end up with. I am surprised by your electrician's comments. Scenario #1 is exactly what you want right?
Your growatt inverter has a setting (12 and 13) for when it wants to switch to Utility (UTILITY in your case is the generator )

If the battery drops below 40% (or whatever value or voltage you set this at) it will switch the Dry Contact, which should/ could start your Generac.
As soon as your setting 13 is reached, the dry contact switches again which should shut off the generac.
Please keep us updated on progress.

 

[magnet creek]

It should really be as simple as connecting two wires from the Dry Contact on the Growatt Inverter to the 2 wires on the Generac.

.
From the youtube video it looks like the generac needs a close on the two wires to start in which case you should wire C and NO.
Unless I am missing something....