Whole Home Backup Generator with Solar

[Freezecat]

Hello all,
I am very new to this and am trying to wrap my head around how I need to set up my system to get what I want. My current goal is to simply set up an automatic natural gas back up generator which I have a pretty good handle on at this point. Where I am running into confusion is on trying to future proof my system. Eventually I would like my home to run primarily on solar with batteries and have the grid as a backup. Then in the event of a power outage run on solar until my batteries become exhausted at which point the natural gas generator will start and charge the batteries if the solar cannot keep up. I hope this is making sense. I ordered a Generac 22kw standby generator which comes with the ATS system and was going to just install that to start, however I also ordered an EG4 Gridboss in the hopes that I could use that in place of the Generac ATS to control the generator for now and eventually build a solar system to connect the the Gridboss as well. My current goal is to simply have the generator kick on when the power goes out automatically as controlled by the Gridboss (I work an hour away from home and want it to be hands free for my wife to give her piece of mind) I had thought this would be simple but in reading through other threads it seems a bit more complicated than I had thought. It seems there are issues with keeping the battery in the Generac charged when connected to the Gridboss and that it may not automatically start the generator. Am I better off just using the Generac ATS for now and keeping the Gridboss for the future/ returning it? Any advice on this topic would be greatly appreciated.

 

[BentleyJ]

Since the GridBoss already has all the connections for Inverters, Smart Ports, AC Coupling and Generator as well as a maintenance bypass, the ATS is is not needed.
From what I've read on this forum and reviewing a few Generac wiring diagrams, it seems most of the time the auto start function is built into the generator control module. This means all you need to do is run 2 hots and a neutral FROM THE UTILITY LINE SIDE OF THE TRANSFER SWITCH IN THE GRIDBOSS. This will keep the battery charged and also signal the control module to start-stop the generator.

Of course this needs to be verified for your model number. There should be a wiring diagram or schematic in the manual.

 

[Freezecat]

Since the GridBoss already has all the connections for Inverters, Smart Ports, AC Coupling and Generator as well as a maintenance bypass, the ATS is is not needed.
From what I've read on this forum and reviewing a few Generac wiring diagrams, it seems most of the time the auto start function is built into the generator control module. This means all you need to do is run 2 hots and a neutral FROM THE UTILITY LINE SIDE OF THE TRANSFER SWITCH IN THE GRIDBOSS. This will keep the battery charged and also signal the control module to start-stop the generator.

Of course this needs to be verified for your model number. There should be a wiring diagram or schematic in the manual.

So part of my plan was to use the Generac Generator Cable as a straightforward way to wire the generator. It's certified for burial and UVexposure and everything. It contains (3) 1 AWG power conductors (1) 6 AWG ground conductors and (9) 18 AWG copper wires for control. If I understand what you are saying correctly I will have to run additional wires from the Gridboss on the Utility side to the Generac specifically to charge the battery as they would need to be larger than the 18 AWG control wires included in that cable to carry the 120V grid power to the generator. Is that correct?

 

[BentleyJ]

I was actually suggesting that we review the wiring diagram first. The 18AWG control wires can be used but instead of connecting inside the ATS (which is not used) they will be connected inside the GridBoss. There should be no need for any additional wires.

The Generac is only going to have a trickle charger to keep the battery full, its not a bulk charger, the generator should have its own 12V alternator to charge the battery after cranking the engine to start it.

 

[Freezecat]

I was actually suggesting that we review the wiring diagram first. The 18AWG control wires can be used but instead of connecting inside the ATS (which is not used) they will be connected inside the GridBoss. There should be no need for any additional wires.

The Generac is only going to have a trickle charger to keep the battery full, its not a bulk charger, the generator should have its own 12V alternator to charge the battery after cranking the engine to start it.

I understand what you mean now, thank you for your reply and when I get the parts in hand I will read through the manuals and diagrams. Thank you for putting me at ease that I did not make a bad decision in buying the Gridboss. I am excited to get working on this project.

 

[kc130up]

You can definitely connect the Generac to the GB. The GB has generator auto start contacts and such on it to make it work.

Having used my GB + Generator twice during testing, the generator "seems" to only power the loads. Just double check if it really charges the batteries when the grid is down.

One other thing to consider, is the THD of the generator at full load. There have been reports of GB's dropping the generator input even when the THD is less than 5%.

 

[Freezecat]

You can definitely connect the Generac to the GB. The GB has generator auto start contacts and such on it to make it work.

Having used my GB + Generator twice during testing, the generator "seems" to only power the loads. Just double check if it really charges the batteries when the grid is down.

One other thing to consider, is the THD of the generator at full load. There have been reports of GB's dropping the generator input even when the THD is less than 5%.

My main concern was there seemed to be conflicting information as to whether the GB would charge the standby battery to start the generator in auto mode but it seems that should be a solvable problem. Forgive my ignorance but what are you referring to when you say THD?

 

[BentleyJ]

You can definitely connect the Generac to the GB. The GB has generator auto start contacts and such on it to make it work.

It depends on the brand of generator. With Generac if it has its own control module the GB autostart contacts are not used.

 

[Freezecat]

It depends on the brand of generator. With Generac if it has its own control module the GB autostart contacts are not used.

The generator I ordered is the Generac Guardian 7043 https://www.electricgeneratorsdirect.com/Generac-Guardian-7043-Standby-Generator/p82547.html

 

[Freezecat]

You can definitely connect the Generac to the GB. The GB has generator auto start contacts and such on it to make it work.

Having used my GB + Generator twice during testing, the generator "seems" to only power the loads. Just double check if it really charges the batteries when the grid is down.

One other thing to consider, is the THD of the generator at full load. There have been reports of GB's dropping the generator input even when the THD is less than 5%.

In looking over the generator specs I found the answer to my question, Total Harmonic Distortion. Generac claims it's less than 5% so we'll see I guess.

 

[BentleyJ]

OK, I will check out link you posted for the 7043

 

[Freezecat]

OK, I will check out link you posted for the 7043

I really appreciate it.

 

[kc130up]

In looking over the generator specs I found the answer to my question, Total Harmonic Distortion. Generac claims it's less than 5% so we'll see I guess.

The issue people have ran into with the GB is even with generators that claim to be <5% THD, the GB still isn't happy.

The theory is, <5% THD is another "embellishment" in the EG4 data sheet.

My generator claims to be < 5% THD < 50% load. I have no idea how to test it so .

 

[BentleyJ]

Page 26 of the manual shows 2 yellow sense wires for L1 & L2 These can be connected to a Smart Port and the port can be configured to shut off when utility power is lost AND battery SoC falls below a set level, say 25%. (Disregard my previous comment regarding connecting to the Line Side of the GridBoss transfer switch. This would autostart the Gen as soon as utility is lost, probably not what you wanted.)

The Blue wire is 120V for the Gen trickle charger. This can be connected to either L1 or L2 of the same Smart Port. I would suggest getting something like this double Ferrule.

Insulated & Non-Insulated Twin Wire Ferrules | Ferrules Direct

Our insulated & non-insulated twin wire ferrules are for use in factory wiring only & power or control circuits.Contact us with any further information.

www.ferrulesdirect.com

Hopefully the smallest breaker that fits the Smart Port will have a screw terminal compatible with the ferrule diameter. I would think an inline fuse would be a good idea on all 3. Although the Generac manual only calls for a fuse on the blue charger wire.

 

[Freezecat]

Page 26 of the manual shows 2 yellow sense wires for L1 & L2 These can be connected to a Smart Port and the port can be configured to shut off when utility power is lost AND battery SoC falls below a set level, say 25%. (Disregard my previous comment regarding connecting to the Line Side of the GridBoss transfer switch. This would autostart the Gen as soon as utility is lost, probably not what you wanted.)

The Blue wire is 120V for the Gen trickle charger. This can be connected to either L1 or L2 of the same Smart Port. I would suggest getting something like this double Ferrule.

Insulated & Non-Insulated Twin Wire Ferrules | Ferrules Direct

Our insulated & non-insulated twin wire ferrules are for use in factory wiring only & power or control circuits.Contact us with any further information.

www.ferrulesdirect.com

Hopefully the smallest breaker that fits the Smart Port will have a screw terminal compatible with the ferrule diameter. I would think an inline fuse would be a good idea on all 3. Although the Generac manual only calls for a fuse on the blue charger wire.

This is incredibly helpful, I can't thank you enough. Connecting to the line side to auto start the generator if utility power is lost is exactly what I want right now and I can swap that to the smart port configuration when I have the cash to get batteries and panels and an inverter setup.

 

[blrmaker]

We have the Generac G007210-10 wired through a combiner box to our 2@18kPv inverters. The 2 wire start is wired to the master inverter, right out of the manual pg 25. The generator starts every Wednesday for 5 minutes to charge the onboard battery and keep the oil circulated. I thought I would have to change a setting in the inverter to do this however the Generac has it programed automatically.

 

[Freezecat]

Page 26 of the manual shows 2 yellow sense wires for L1 & L2 These can be connected to a Smart Port and the port can be configured to shut off when utility power is lost AND battery SoC falls below a set level, say 25%. (Disregard my previous comment regarding connecting to the Line Side of the GridBoss transfer switch. This would autostart the Gen as soon as utility is lost, probably not what you wanted.)

The Blue wire is 120V for the Gen trickle charger. This can be connected to either L1 or L2 of the same Smart Port. I would suggest getting something like this double Ferrule.

Insulated & Non-Insulated Twin Wire Ferrules | Ferrules Direct

Our insulated & non-insulated twin wire ferrules are for use in factory wiring only & power or control circuits.Contact us with any further information.

www.ferrulesdirect.com

Hopefully the smallest breaker that fits the Smart Port will have a screw terminal compatible with the ferrule diameter. I would think an inline fuse would be a good idea on all 3. Although the Generac manual only calls for a fuse on the blue charger wire.

I finally had some time to go through the manuals for the gridboss and Generac and I am not seeing the information you referenced on page 26 of either manual. Which manual were you looking at and where did you find it?

 

[BentleyJ]

Its in the Installation Manual

 

[Mercracing]

Its in the Installation Manual

Hello all,
I am very new to this and am trying to wrap my head around how I need to set up my system to get what I want. My current goal is to simply set up an automatic natural gas back up generator which I have a pretty good handle on at this point. Where I am running into confusion is on trying to future proof my system. Eventually I would like my home to run primarily on solar with batteries and have the grid as a backup. Then in the event of a power outage run on solar until my batteries become exhausted at which point the natural gas generator will start and charge the batteries if the solar cannot keep up. I hope this is making sense. I ordered a Generac 22kw standby generator which comes with the ATS system and was going to just install that to start, however I also ordered an EG4 Gridboss in the hopes that I could use that in place of the Generac ATS to control the generator for now and eventually build a solar system to connect the the Gridboss as well. My current goal is to simply have the generator kick on when the power goes out automatically as controlled by the Gridboss (I work an hour away from home and want it to be hands free for my wife to give her piece of mind) I had thought this would be simple but in reading through other threads it seems a bit more complicated than I had thought. It seems there are issues with keeping the battery in the Generac charged when connected to the Gridboss and that it may not automatically start the generator. Am I better off just using the Generac ATS for now and keeping the Gridboss for the future/ returning it? Any advice on this topic would be greatly appreciated.

Freezecat,

I have a Sol-ark 15K with batteries and a Generac 25kw liquid cooled industrial standby generator so I can not speak from an educated position on the EG4 equipment, but I do have a few thoughts that might be helpful. When the electrician added the generator to my system the connection was made to the Sol-ark (functioning as the transfer switch and two wire start). My inverter (set to the widest power tolerance settings) does not have an issue with staying connected to the generator. That having been said, the Sol-arks programming options for controlling the generator are not very good. If you use any of the Time Of Use (TOU)features to control the discharge of the batteries you are forced to have the charging Time Of Use options turned on so that the generator will start, the issue with that is it also makes it possible for the inverter to grid charge the batteries when the utility is present. The other option is no TOU function to limit battery discharge percentage (all TOU boxes off) and then the generator will start when the grid is down. Again, I would stress this may not apply to the EG4 equipment, but it is worth double checking.

Suggestions

1- Use EG4 Chargeverters or the Eco worthy equivalent to connect the generator to the battery bank while using the ATS that came with gen set on the utility input to the inverter if you only want them to operate in a grid outage.

2- Use the newer Chargeverter's dry contacts to control the generator and allow it to run even if the grid is up (based on SOC or Voltage).

3- Install the generator using it's ATS on the utility side of the input to the inverter allowing the generator to operate itself in the manner it was designed function. Using it in this fashion maybe you could set the inverter to "grid charge" in settings, but that would probably have to be changed during the outage unless you were willing to let the system grid charge normally.

Having tried running the generator through the Sol-ark I feel like allowing the generator to charge the batteries through the Chargeverter is a better option as it allows the inverter to keep putting out clean and stable power without having to worry about the generator picking up and putting down loads (flickering lights). The other thing I would strongly suggest is using a manual transfer switch to allow the generator to be switched to powering the home in the event that the inverter is broken.

 

[EddieReynolds70]

Generac Help Center

support.generac.com

 

[EddieReynolds70]

Generac Help Center

support.generac.com

information on Two wire kit that you can add to existing generac generators to enable two wire start/stop