Connect 17k. Cummins Standby to Outback Charger

[Circle Star Ranch]

I have my panels running to charger, back to batteries, then to inverter (which is a POS I need to replace), and finally to the main 100amp breaker on panel. The generator is running directly to 60 amp breaker on panel box that I turn on when need to run house due to low batteries (turning off 100 am main to inverter as to not back flow and burn things up). I need to know how to affix the generator to the Outback charge controller in order to charge batteries instead of running the house for hours on it. Please be simplistic as I am learning all of this on my own. People don't like to help around here by making others more efficient. Not looking to become an electrician, just be self-sustaining while building a ranch for troubled and homeless teens to be peer mentors working with special needs, with a dude ranch twist. I am a special needs teacher who promotes peer tutoring and mentors in the school setting, this would be something for summer so kids continue to learn new skills. Such as, small engine repair, water-distribution systems, welding, building construction, maintaining and working with livestock (chickens, ducks, lambs, goats, pigs, and one day horses). I am doing this all on my own with my small teacher salary. Keeping it cheap and simple is best for me. Appreciate the flow of knowledge, something I will pass to the teens to tutor autistic children with. Let me know if you need more info on system. It is very basic.

[raysun]

All-in-one units like the Growatt are cheap and convenient, but with all the functions in one chassis, it's hard to decypher what all goes on under the hood. The Growatt is designed to connect to a battery (24V in this case), a solar array, an AC source (grid or generator), and AC loads (via a standard electrical load panel.)
Your profile lists an Outback FM80 charge controller, and about 2kW PV (photovoltaic - solar panel) array. I assume the FM80 is being used to manage the array, and charge the battery.

The Growatt does not have solar panels attached to its PV input, correct?

Since the system is 24V the four 6V battery blocks are configured in series to create a 24V @ 400AH battery.

On to your question...
The Growatt has a 120V AC INPUT connection meant to attach to an AC source like the power grid, or for off-grid, to an AC generator like your Cummins. The Growatt has an internal transfer switch, which will sense the presence of AC on its input, and will automatically route that input to the Growatt's AC Output terminals feeding the main load panel. The internal transfer switch operates in a similar manager to the external transfer switch now being used to select between Inverter AC OUT and Generator AC OUT to feed the main load panel.
The manual seems to specify 60A AC Input current rating of the transfer switch, though it does recommend a 40A circuit breaker "for 3kVA". Check with the equipment vendor for the transfer switch AC current input specification. (The existing 60A circuit breaker *should* be OK.)
Note the generstor's 17kVA output is way over-rated for the inverter's AC Input. That simply means the inverter charger and 3kW "downstream" loads won't draw anywhere near the generator's output capacity. The engine appears to run at 3600 no matter the load, do likely wastes fuel when powering small loads. Of course, with the generator powering "house loads" and battery charging simultaneously, the work per pound of fuel will increase over the current situation.
With AC Input, the inverter also switches function from battery inverter to battery charger. With proper configuration the Growatt AC battery charger will work in concert with the PV charge controller to charge the battery.
Note the battery's maximum charge current is rated 100A. The combined charge current of the FM80 and the Growatt should not exceed this (during the Bulk Charging phase.)
I suggest contacting the Growatt vendor for technical support related to connecting the generator, and programming the inverter charger for the specific charging parameters.

Growatt manual - AC Input wiring

[Circle Star Ranch]

Correct, the panels are going to the FM80 charging the batteries but they do go into the Growatt for normal powering the house panel. I see what you are saying, connect the Cummins to the Growatt and it will automatically sense the AC input and at the same time charge the batteries? Can I leave the array to charge the batteries through the FM80? They both should stop charging when the batteries are full, correct? Thank you, I will contact the Growatt vendor to get specific charging parameters. Perfectly the information I needed.

[raysun]

Correct, the panels are going to the FM80 charging the batteries but they do go into the Growatt for normal powering the house panel.

I don't quite understand. Is the PV array connected to both the FM80 and to the Growatt?

...connect the Cummins to the Growatt and it will automatically sense the AC input and at the same time charge the batteries?

Yes, remove the generator hot circuit lead between the 60A circuit breaker and the external transfer switch. Connect that lead to the AC IN Hot terminal on the Growatt. (Of course, the Neutral and Ground leads from the Cummins should be connected to the Growatt's N and G terminals.)

Can I leave the array to charge the batteries through the FM80?

Yes, the FM80 should be the only charger connected to the array in order to properly charge the battery.
Alternately, disconnect the PV array from the FM80, and connect the array to the Growatt's charge controller input. Like the FM80, the Growatt MPPT controller is rated 80A, so will handle the 2000W array. The benefit of using the Growatt MPPT, is the Growatt may have internal logic to automatically control both chargers' current to the 100A maximum rating specified by the battery.

Growatt manual. Maximum combined charge current is programmable.

In this latter case, the FM80 becomes surplus, but in an off-grid environment, I'd never object to having a stand-by charge controller ready to put into service should the main controller fail. After disconnecting the FM80 from the array, disconnect it from the battery. That might be as simple as opening a circuit breaker, if one is installed between the FM80 and the battery.
Also, should the Growatt be replaced at some point, the FM80 is in place to take on the battery charging function should it be needed.

[Circle Star Ranch]

The array comes in to FM80 and lines go to batteries, the battery line comes back to Growatt inverter and then to the electrical breaker panel for house. Basically - Solar Panels > FM80 > Batteries > Growatt > Breaker Box

I am trying to connect my RS17A Cummins Home Standby to the Growatt, as you stated previously. I run on LP gas but from what I read, it is still a. diesel generator. Is this still acceptable?

[raysun]

The array comes in to FM80 and lines go to batteries, the battery line comes back to Growatt inverter and then to the electrical breaker panel for house. Basically - Solar Panels > FM80 > Batteries > Growatt > Breaker Box

OK. That's a conventional setup using an external charge controller.

I am trying to connect my RS17A Cummins Home Standby to the Growatt, as you stated previously. I run on LP gas but from what I read, it is still a. diesel generator. Is this still acceptable?

As far as I know, the fuel used to run the generator's engine may influence the maximum AC Output power, but doesn't change the basic nature of the device. If the unit is suitable configured for one fuel, it should be suitable when configured for a compatible alternate fuel. That being said, the Cummins Quiet Connect series such as the RS17A, are offered as LP/NG fuel units. No mention is made of diesel as a fuel.
Connecting the generator to the Growatt will involve wiring the AC output of the generator to the AC Input terminals of the inverter. The Growatt is a 120VAC unit, so the connection from the RS17A will need to be 120VAC as well. The Growatt's internal transfer switch appears to be rated @ 60A, so will accept (120V × 60A =) 7200 Watts maximum from the generator. If the Growatt works in typical fashion, when AC Input is applied, it's internal transfer switch will connect the AC Input to AC Output, effectively feeding "house loads" from the generator. At the same time, the inverter switches to battery charging mode, and the Growatt will draw additional current from the generator for that purpose. It appears the battery charger can accept 30A @ 120VAC, so a maximum of 3600 Watts for battery charging. Into the 24V battery, the charge current could be as much as 145ADC. That happens to be the maximum charge current the battery will safely accept.
Did an owner's manual accompany the generator?

[Circle Star Ranch]

Yes, I do have an owners manual. I didn't quite understand all of them jargon but am getting better with it. The way you explained it is easier to understand than reading the book. You should write a manual called "Solar Living for Dummies" :-) Some of us need it laid out to understand. This is my first go at off-grid living, not doing terribly bad but need to be more efficient to get everything up and running to start the Special Needs Dude Ranch. I have to set up a small system to run the chicken coop, heat and light. I figure two 100w panels to CC and 1 12v BattleBorn. Should be able to run a small light and a heat lamp through the evenings and charge in the day with a switch to shut off heat lamp. and light on daylight hours. Setting up a 12' round, 3' deep pool for ducks and going to run just a panel for a heating rod to de-ice any freezing from the night. Eventually, a small system to run lights in the barn and some solar area lights for the property.

Just a thought, is there a way to set the generator to run 120w or do I have to replace the breakers in the generator to accommodate the load? Or even something inline that converts or reduces the load?

[raysun]

"Solar Living for Dummies"

I may be uniquely qualified.

The output AC voltage of the generator must match the input AC voltage of the inverter. I'm guessing the house load circuits are all wired 120V. There are no 240V loads, (electric stove/oven, electric dryer, 240V well pump, etc.) correct?