I am completing my solar installation and have run across an issue I don’t know how to answer. I have 2 Solark 15k inverters that will be connected in parallel to charge 4 EG 4 power pro batteries. I have asked my generator dealer to connect it to my Solark inverters at the grid connections as I will be off grid. He brought up the issue of “harmonic Distortion “. He believes it would be to great to connect to my inverters. I know via online videos it is done successfully. I have also reached out to Solark and asked if they could provide anything in writing that addresses this concern. The simple answer is nothing, but they assured me it works just fine that the voltage and frequency ranges are expanded and they handle multiple generator platforms. How do I explain or where do I look to help answer the questions of my Generac dealer. He is a really kind man and he has never hooked into off grid before and he doesn’t want to damage my equipment.
24kw Generac generator to off grid system and Harmonic Distortion.
- Thread starter Ttdf12
- Start date
seneysolar
24V
The Solark inverter simply wont connect to it if voltage or frequency is out of spec (that you choose).
Solark prefers less than 15% thd which is very generous.
Heres the page from the manual that describes setting the range for voltage and frequency
I feel reasonable sure it will be successful, but my feelings are not facts to share, Is the 15% or less distortion the same for generators over 19.2kw that are attached to grid inputs. He used a calculator that Generac had and I am not sure we added all the right information, but it came out with about 35% harmonic distortion. In the event we failed to consider some of the information, is there an independent tool that can calculate this information?
seneysolar
24V
What calculator did you use?
DIYrich
Solar Wizard
I would be surprised if a 24kW generac has more than 10% thd. In general, the larger the generator, the less thd it has. Limit your draw to 17kW, and you should be fine. If you are really worried, then get 3 chargeverters and charge your battery directly.
DIYrich
Solar Wizard
Basic setting, advanced tab, gen limit
TM48
Solar Wizard
Yeah it's generous that Solark will pass 15% THD right thru to your finest electronics. To my knowledge none of these inverters "clean up" any generator pass thru power. In other words they don't make inverter clean power out of a cheap generator. If you need clean power charge your batteries with a charger and let the inverter make the power.
This was a totally off grid install. The installer made a little mistake. Since grid wasn’t available, he simply wired the Generac to the grid input of the inverters. It turns out that the grid terminals are much more selective about power quality. Wired to generator input and the inverters were happy and willing to pass through and charge. Tho the Generac is not an inverter type, they do output acceptable quality power for practically any appliance.
50ShadesOfDirt
Solar Addict
- Joined
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I assume you do not have a generator purchased yet, and you are talking to a Generac authorized dealer. The typical issues with inverters and generators are:
- does the inverter accept the generator's output for charging the battery-bank (inverter-gen or non-inverter-gen)
- does the inverter also pass-thru the generator output, while charging (gen sizing)
- how does inverter signal gen to start (usually some kind of two-wire signaling system)
The other related issues are of a power-quality nature, such as THD and/or surges, and what you might want to do about each.
The final issue is of a warranty nature, and if Generacs are involved, let's start here: Generac usually doesn't allow their whole-house gen standby backup line to be used in an off-grid environment; if you try this, they will most likely void the warranty ... they'll still sell you the unit, it just won't have an effective warranty. Generac has super-strict installation requirements, and it is best for these units to be installed by an authorized dealer, to preserve warranty. For off-grid folks, Generac has the ECO-Gen lineup, which is purpose-built for off-grid (but which has it's own problems). If your installation is somehow grid-tied, then the Generac standby unit might fit, because the Sol-Ark will accept grid power or generac power into it's grid input connection. If you are fully off-grid, then only the Generac would be fed into the Sol-Ark's grid input connection (and Sol-Ark is now happy), but this voids the Generac warranty (and Generac, the company, is now unhappy).
The question of which generator is suitable for inverter-charging can only be answered by the inverter manufacturer. If the Sol-Ark folks are saying they are good with Generacs, then you are good to use them (warranty aside), regardless of THD output. Generac doesn't really post their THD values for any given model, and rule of thumb is that they put out more than 5%, but probably less than 10% or so. If Sol-Ark is saying they can accept up to 15% THD from a generator, with all other power issues (frequency, voltage) in reasonable proximity to grid power, then you are good to go. It would be better if they list support for a generator, but not all inverter manufacturers do. The next best thing to do is to use an inverter-gen, which almost always puts out less than 5% THD (a Honda inverter-gen usually does 3% THD, and a certain Westinghouse open-frame model can put out 5%, but these have two-wire start issues, sizing issues, etc., because they are "portable" units, and not like a Generac "standby" unit).
After all of the above is sorted through, you'll want to "size" the generator for the load (what it takes to charge the battery, and what other house loads are happening while inverter is in pass-thru mode). Oversize the gen so that no more than 75% of available rated power handles your charging *and* pass-thru loads, to produce stiff power similar to the grid. My guess is that the 22kw and larger models will be what you are after, but run through the sizing exercise to be sure.
For THD issues, ignore it (IMHO), because most high-quality generators (inverter-gen at roughly 3%, or open-frame at 5 to 10%) usually put out a good enough level of THD that we can live with; everything else is marketing. You ignore THD because, even though the gen puts out a good THD level (as does the grid), every device in your house is putting THD back out on the house wiring, so you aren't really doing any good (from THD perspective). On the other hand, you can do something about surges, and surges kill more equipment than THD does anyway (every device in your house puts out micro-surges, and bigger devices and/or the grid puts out big surges). So, implement surge protection at the inverter-level (or grid level), at the load center or circuit breaker panel, and at the device level (for devices you care about).
Again, the real big issue is does your inverter officially accept the gen's output? If inverter-gen, answer is usually yes. If non-inverter-gen, answer is usually maybe. If off-grid, it is *never* a Generac standby gen, unless you choose to go "self-supporting" (and you have an authorized gen dealer on your side). It could be a Generac eco-gen, if you are brave enough to go this route. Next big issue is two-wire start support, so inverter can signal gen to start/stop (generacs are very good at this, most other gens can be supported with some surgery).
I used to run Generacs in my rural, off-grid location, and for numerous reasons, had to move away from them. I now run Westinghouse open-frame gens (with my off-grid Magnum LF 4024 inverter).
Hope this helps ...
- does the inverter accept the generator's output for charging the battery-bank (inverter-gen or non-inverter-gen)
- does the inverter also pass-thru the generator output, while charging (gen sizing)
- how does inverter signal gen to start (usually some kind of two-wire signaling system)
The other related issues are of a power-quality nature, such as THD and/or surges, and what you might want to do about each.
The final issue is of a warranty nature, and if Generacs are involved, let's start here: Generac usually doesn't allow their whole-house gen standby backup line to be used in an off-grid environment; if you try this, they will most likely void the warranty ... they'll still sell you the unit, it just won't have an effective warranty. Generac has super-strict installation requirements, and it is best for these units to be installed by an authorized dealer, to preserve warranty. For off-grid folks, Generac has the ECO-Gen lineup, which is purpose-built for off-grid (but which has it's own problems). If your installation is somehow grid-tied, then the Generac standby unit might fit, because the Sol-Ark will accept grid power or generac power into it's grid input connection. If you are fully off-grid, then only the Generac would be fed into the Sol-Ark's grid input connection (and Sol-Ark is now happy), but this voids the Generac warranty (and Generac, the company, is now unhappy).
The question of which generator is suitable for inverter-charging can only be answered by the inverter manufacturer. If the Sol-Ark folks are saying they are good with Generacs, then you are good to use them (warranty aside), regardless of THD output. Generac doesn't really post their THD values for any given model, and rule of thumb is that they put out more than 5%, but probably less than 10% or so. If Sol-Ark is saying they can accept up to 15% THD from a generator, with all other power issues (frequency, voltage) in reasonable proximity to grid power, then you are good to go. It would be better if they list support for a generator, but not all inverter manufacturers do. The next best thing to do is to use an inverter-gen, which almost always puts out less than 5% THD (a Honda inverter-gen usually does 3% THD, and a certain Westinghouse open-frame model can put out 5%, but these have two-wire start issues, sizing issues, etc., because they are "portable" units, and not like a Generac "standby" unit).
After all of the above is sorted through, you'll want to "size" the generator for the load (what it takes to charge the battery, and what other house loads are happening while inverter is in pass-thru mode). Oversize the gen so that no more than 75% of available rated power handles your charging *and* pass-thru loads, to produce stiff power similar to the grid. My guess is that the 22kw and larger models will be what you are after, but run through the sizing exercise to be sure.
For THD issues, ignore it (IMHO), because most high-quality generators (inverter-gen at roughly 3%, or open-frame at 5 to 10%) usually put out a good enough level of THD that we can live with; everything else is marketing. You ignore THD because, even though the gen puts out a good THD level (as does the grid), every device in your house is putting THD back out on the house wiring, so you aren't really doing any good (from THD perspective). On the other hand, you can do something about surges, and surges kill more equipment than THD does anyway (every device in your house puts out micro-surges, and bigger devices and/or the grid puts out big surges). So, implement surge protection at the inverter-level (or grid level), at the load center or circuit breaker panel, and at the device level (for devices you care about).
Again, the real big issue is does your inverter officially accept the gen's output? If inverter-gen, answer is usually yes. If non-inverter-gen, answer is usually maybe. If off-grid, it is *never* a Generac standby gen, unless you choose to go "self-supporting" (and you have an authorized gen dealer on your side). It could be a Generac eco-gen, if you are brave enough to go this route. Next big issue is two-wire start support, so inverter can signal gen to start/stop (generacs are very good at this, most other gens can be supported with some surgery).
I used to run Generacs in my rural, off-grid location, and for numerous reasons, had to move away from them. I now run Westinghouse open-frame gens (with my off-grid Magnum LF 4024 inverter).
Hope this helps ...
Personally I wouldn’t run a Generac for the reasons you mentioned, but I wouldn’t tell anyone to replace it unless they were experiencing issues. A friend who is an electrician hates them for those reasons and more. His main issue that he’s seen is a bad charger. Since most of his calls are for out of warranty , he simply deactivates the existing charger, and installs a “Battery Tender” brand charger. He also replaces the cooked battery.
I have actually purchased the 24kw whole house Generac generator prior to deciding on solar. So it is what I have. The dealer is unfamiliar with Solark 15k inverter and is hesitant to assist in connecting to the inverter. Trying to find documentation to show it will not damage the inverter or Generac. I understand that Solark can adjust frequency and voltage range higher or lower on each. If I reduce the generator to about 75% it should reduce thd issues. I am currently building to go off grid and I may be out of luck with warranty and generator. Am I correct in what I am saying ? Is there some way I can test the output of power from Generac and the output from Inverter with and without the generator attached? For thd and surge?
DIYrich
Solar Wizard
Both will be fine.
sol-ark will not "adjust" the generator. It treats it like the grid.
Either connect the generator to the grid input (with an ATS on the generator) or to the gen input port. Set the Gen Limit on the Sol-ark to 18kW, and you are done.
Option 2: get 3 or 4 chargeverters. Connect only the CV to the generator. Run the generator when you want to recharge the batteries. Version 2 of the chargerverter can cintrol the generator. Put in a manual transfer switch incase you want to bypass the sol-ark and run your house directly from the generator.
Thank you for the ideas! If I already have the Generac on an automatic transfer switch (ATS), what if I replace primary grid input with solar as primary. Install 240v outlets for each of the chargeverters from the main panel and run the chargeverters to poasitve fused buss and negative buss. Then send that input to generator input of each Solark inverters and limit the output and have it charging batteries only? Would that accomplish what I need to do? That way if and when the batteries reach dod 80% and no solar available, the Generac will run as normal powering the house and the batteries will charge and not be required to supply power until a predetermined point (95%) for example.
Offgrid Jungle
Solar Enthusiast
Unnecessary. Just wire the gen up to the inverters and move on...I set my inverter to start the gen if the battery gets to 30% SOC. My gen is a little 8000 diesel so I set the charge rate to 2000 watts (since the gen would also be carrying house loads when it's running)
KISS - if the system needs the gen, it needs the gen.
KISS - if the system needs the gen, it needs the gen.
I think that calculator calculates harmonic distortion of your loads, not harmonic distortion of the generator. 24KW generator on the grid terminals should work just fine. Install the CTs, check Gen Peak shaving and set limit to 17KW.
Concerns about Generac warranty are real. If your generator is still under warranty you probably should use an ATS to switch between inverter and generator.
50ShadesOfDirt
Solar Addict
- Joined
- Jan 8, 2021
- Messages
- 706
So, you've indicated you already purchased the Generac standby unit, and will use it in your off-grid setup. You can ask your Generac dealer to confirm, but the warranty will probably be void now, because of being in an off-grid scenario. If there is no grid-connection, a standby wasn't supposed to be used in an off-grid, you were supposed to use the eco-gen instead. Don't know if that situation has changed since my experience, and I long ago switched to two portable open-frame gens to replace the single big generac.
The Generac worked for awhile in my off-grid scenario (it's 2-wire start system worked well with my magnum auto-start module, and started and stopped like a dream), but I occasionally got error codes thrown at me from the generac, and support issues related to stuff breaking in weird ways inside the Generac. I think this was from off-grid issues, and perhaps from my wiring, but never really got to root cause on them (I didn't have the service manual, to get to root cause).
I knew the warranty would be void and chose to go self-supporting. It worked well for as long as it ran, but it did not like being in an off-grid scenario, and without the super-secret "service manual", I couldn't support it rurally, and had to move away from Generacs.
You will want to haunt the Ziller Electric forum for Generacs:
zillerstore.com/generac-air-cooled-generators-705132
As we don't have access to the service manual, there were many authorized technicians on the Ziller site, and I got at some of the info that way. Even then, I consider it impossible to support a (rurally located) Generac without that service manual, and that's yet another reason I had to move away from them. If your authorized Generac dealer will take you under his wing, you might get away with the self-support route, as long as you are OK with paying for parts and labor (Generac itself won't give you that fancy 7-year or longer warranty, if off-grid).
I hope your experience is much better, and please do keep us all posted ... more Generac experiences being posted (good or bad) ends up being better for all of us!
The Generac worked for awhile in my off-grid scenario (it's 2-wire start system worked well with my magnum auto-start module, and started and stopped like a dream), but I occasionally got error codes thrown at me from the generac, and support issues related to stuff breaking in weird ways inside the Generac. I think this was from off-grid issues, and perhaps from my wiring, but never really got to root cause on them (I didn't have the service manual, to get to root cause).
I knew the warranty would be void and chose to go self-supporting. It worked well for as long as it ran, but it did not like being in an off-grid scenario, and without the super-secret "service manual", I couldn't support it rurally, and had to move away from Generacs.
You will want to haunt the Ziller Electric forum for Generacs:
zillerstore.com/generac-air-cooled-generators-705132
As we don't have access to the service manual, there were many authorized technicians on the Ziller site, and I got at some of the info that way. Even then, I consider it impossible to support a (rurally located) Generac without that service manual, and that's yet another reason I had to move away from them. If your authorized Generac dealer will take you under his wing, you might get away with the self-support route, as long as you are OK with paying for parts and labor (Generac itself won't give you that fancy 7-year or longer warranty, if off-grid).
I hope your experience is much better, and please do keep us all posted ... more Generac experiences being posted (good or bad) ends up being better for all of us!
DIYrich
Solar Wizard
Since you are off-grid:
Generator -> panel
Panel (30 amp breakers) -> Chargertervers -> Battery
Panel (70 amp breakers) -> Grid Input of each of the Sol-Arks
Keep the 70 amp breaker off when you don't want to feed power directly to the two Sol-Arks.
Version 2 of the Chargeverter has 2 wire start for the Generator. Start charging at 20% (or 10%), and cutoff at 50%.
I have 5 eg4 power pro all weather batteries in parallel on a 2 Victron Energy Lynx Distributor | 1000A | M8 connected in series. I am thinking of adding 2 more power pro batteries to make 7 total in parallel . What bus bars can I use to allow this expansion?
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