EG-4 18kw pv inverter, generator won't with it

[Cmiller]

Me, not knowing how inverter accepts generator power would think inverter manufactures
would only use generator to power battery. Something like a separate charge better.
That would make a desirable system.

Is this how inverter manufactures are designing? Any thoughts about this?

I think you are asking if the gen input directly feeds a separate charger in the inverter...?

The "charger" portion in an inverter/charger is simply the inverter circuitry working in reverse to draw from the AC bus to charge the batteries. AC input, whether grid or gen, is just sync'd up to, then connected in via the transfer relay. (Really just a contactor.) The inverter is always monitoring the AC quality and if it deviates outside of acceptable range the transfer relay contacts are opened up again, and inverter resumes pushing power from batteries to AC bus.

Grid input vs gen input function the same, and pass power on through to loads whenever connected. The only difference is that the gen input is supposed to be less "picky" about the power quality, and is supposed to not allow "sell-back" out of the gen terminals.

That is the shortened, condensed explanation. The high frequency AIO inverters such as 18kPv and Sol-Ark have step up/step down dc-dc converters between battery voltage and high voltage DC bus. Then the actual DC-AC inverter runs between high voltage DC bus and AC bus. (Mppt inputs convert directly from PV to high voltage DC bus.) This extra step between AC and DC does make it harder for the unit to adjust to sudden power changes such as well pump, etc. shutting off and creating an excess of power on the high voltage DC bus, as multiple steps need to be taken to accommodate for the change.

Hopefully that answers your question, and helps to shed some light on internal operation.

One more note* I agree with you that if the UPS accepted the power from the Generac, it almost can't be "dirty" generator power, as UPSs tend to be pretty picky! Definitely would sound to me like something that may need to be worked on from the inverter side!

We did have one job where 3 Sol-Arks would push VARs to a 45kW genset (this was a 3 phase setup), causing it to actually throw an overload error! I believe that issue was then corrected with newer firmware that must have reacted better to the generator power, or stayed sync'd better.

 

[Warden]

Will be keeping a close eye on this one, I have a generac guardian 14k that has been working pretty good with my Outback Power system but am looking at swapping it out with the EG4 18K. This would definitely be a deal breaker for me.

 

[SparkyJJO]

Will be keeping a close eye on this one, I have a generac guardian 14k that has been working pretty good with my Outback Power system but am looking at swapping it out with the EG4 18K. This would definitely be a deal breaker for me.

Why swap your outback for the 18kpv?

 

[Warden]

Why swap your outback for the 18kpv?

Had a bad AC board - got it replaced and now about 3 weeks later having more problems and they are sending me another AC board replacement. The house is an off grid short term rental so I can't afford to be having issues.

 

[JJB]

I think you are asking if the gen input directly feeds a separate charger in the inverter...?

The "charger" portion in an inverter/charger is simply the inverter circuitry working in reverse to draw from the AC bus to charge the batteries. AC input, whether grid or gen, is just sync'd up to, then connected in via the transfer relay. (Really just a contactor.) The inverter is always monitoring the AC quality and if it deviates outside of acceptable range the transfer relay contacts are opened up again, and inverter resumes pushing power from batteries to AC bus.

Grid input vs gen input function the same, and pass power on through to loads whenever connected. The only difference is that the gen input is supposed to be less "picky" about the power quality, and is supposed to not allow "sell-back" out of the gen terminals.

That is the shortened, condensed explanation. The high frequency AIO inverters such as 18kPv and Sol-Ark have step up/step down dc-dc converters between battery voltage and high voltage DC bus. Then the actual DC-AC inverter runs between high voltage DC bus and AC bus. (Mppt inputs convert directly from PV to high voltage DC bus.) This extra step between AC and DC does make it harder for the unit to adjust to sudden power changes such as well pump, etc. shutting off and creating an excess of power on the high voltage DC bus, as multiple steps need to be taken to accommodate for the change.

Hopefully that answers your question, and helps to shed some light on internal operation.

One more note* I agree with you that if the UPS accepted the power from the Generac, it almost can't be "dirty" generator power, as UPSs tend to be pretty picky! Definitely would sound to me like something that may need to be worked on from the inverter side!

We did have one job where 3 Sol-Arks would push VARs to a 45kW genset (this was a 3 phase setup), causing it to actually throw an overload error! I believe that issue was then corrected with newer firmware that must have reacted better to the generator power, or stayed sync'd better.

Hi


Thanks for taking time to explain and educating me. I now understand how to set inverter parameters to get generator and inverter to work together. Thing is I see now how inverter system works with generator and no way I want to use their system. Future problems is all I see, not being able to match generator full output to load causing inefficiency or overload, possibly at times generator will fault out with over voltage, may have to oversize generator for load spikes, these are just a few of the problems.

In this forum member nathandeb mentioned using a chargeverter instead which makes since. So me not understanding inverter generator input thought inverter would have something similar to a chargevert, WHA what a disappointment. I now can see I have to purchase a chargeverter to do
what I want.


Thanks for the help. JJB

 

[Quattrohead]

The 18k now has generator assist and a bunch of new generator features.

 

[Quattrohead]

And other resent updates to the firmware and monitoring system.
Firmware 1919 along with the monitoring updates -

 

[Quattrohead]

BTW this thing is a beast, mine took some 3-5 second loads of 13.1kw tonight. It did not shut down or bypass, did snarl a bit though

 

[ksmithaz1]

"Generator Boost" was something I was bitc... umm complaining about. Good to see it was implemented.

 

[murmeister]

I'm traveling the 18Kpv/Generac road, as well. After finally getting it to remote start based on SOC, I found that it would NOT charge my batteries, but would supply load to the house. Upon urging from SS, I updated the firmware to 1919, now my Solar input faults regularly and the system switches to grid-only input.

It's exceedingly frustrating to have bright sun and see 0 watts coming in from PV, 100% SOC on the batteries, and be pulling the entire load from the grid - all because the inverter hiccuped and no longer accepts PV, therefore, the battery is off-limits, too.

I'm awaiting a roll-back to v1717 of the firmware. v1919 does have a lot of enhancements related to the generator - and I can verify that it did, in fact, charge my batteries from the generator. This came at the expense of reliable solar input. Perhaps a separate chargeverter may be in my future.

I'll report back here if/when I emerge from this with a system that works like I expect it to.

 

[Warden]

I'm traveling the 18Kpv/Generac road, as well. After finally getting it to remote start based on SOC, I found that it would NOT charge my batteries, but would supply load to the house. Upon urging from SS, I updated the firmware to 1919, now my Solar input faults regularly and the system switches to grid-only input.

It's exceedingly frustrating to have bright sun and see 0 watts coming in from PV, 100% SOC on the batteries, and be pulling the entire load from the grid - all because the inverter hiccuped and no longer accepts PV, therefore, the battery is off-limits, too.

I'm awaiting a roll-back to v1717 of the firmware. v1919 does have a lot of enhancements related to the generator - and I can verify that it did, in fact, charge my batteries from the generator. This came at the expense of reliable solar input. Perhaps a separate chargeverter may be in my future.

I'll report back here if/when I emerge from this with a system that works like I expect it to.

So on the latest firmware your PV input breaks on the inverter, but does the generator charge the batteries now?

 

[JJB]

BTW this thing is a beast, mine took some 3-5 second loads of 13.1kw tonight. It did not shut down or bypass, did snarl a bit though

Thanks for educating me more. Best thing is wait a bit, it's getting better. I'll be back home next week and firmware update
will be first on my list.

 

[ksmithaz1]

Sounds close, not proceeding as fast as I expected, but I can see they are on the right path. I'm running 1717 still, but I don't have grid connected at all. I have a chargeverter as well, I used it to supplement the batteries but I figured out that it was less expensive to just let my ATS flip everything over. In a true off-grid with a genny i would want the "boost" function maybe cutting on the genny at 20%, off at 40%, with a little play to dip to 10% before panic. This would enable you to run thru the night without beating up the genny. Remains to be seen if the inverter will hold up to continuous use. I'm right at 18MW so far, this summer should be fun to watch.

The other function I want is the ability to take one or the other unit offline for maintenance without shutting everything down. The plan is to get a 3rd unit. In a perfect world I take them offline one at a time for upgrade, or in the case of a failure it just keeps on chugging along.

 

[murmeister]

So on the latest firmware your PV input breaks on the inverter, but does the generator charge the batteries now?

I ran two tests and the generator does charge the batteries as expected. The SOC values for start and stop were honored.

The PV problem is intermittent, and seems to only happen when the batteries are full. However, the inverter also randomly decides to switch to grid only mode during the evening when there's obviously no solar input. We can tell something is going on because the lights flicker and the UPS systems do a quick beep. When we check the monitoring app, we see we are pulling only from the grid - even though the battery has plenty of SOC (over 90%) that is nowhere near it's cutoff.

 

[JJB]

Sounds close, not proceeding as fast as I expected, but I can see they are on the right path. I'm running 1717 still, but I don't have grid connected at all. I have a chargeverter as well, I used it to supplement the batteries but I figured out that it was less expensive to just let my ATS flip everything over. In a true off-grid with a genny i would want the "boost" function maybe cutting on the genny at 20%, off at 40%, with a little play to dip to 10% before panic. This would enable you to run thru the night without beating up the genny. Remains to be seen if the inverter will hold up to continuous use. I'm right at 18MW so far, this summer should be fun to watch.

The other function I want is the ability to take one or the other unit offline for maintenance without shutting everything down. The plan is to get a 3rd unit. In a perfect world I take them offline one at a time for upgrade, or in the case of a failure it just keeps on chugging along.

Interesting, learned a new word genny,

 

[ksmithaz1]

BTW this thing is a beast, mine took some 3-5 second loads of 13.1kw tonight. It did not shut down or bypass, did snarl a bit though

Since 1717 I've not had any problems that were not related to battery comm/closed loop sending panics to the inverters. It has been a pretty steady stream of firmware updates everywhere up until late fall. My 4T HVAC raised he11 thru the summer, but it always started even without any soft-start stuff. Adding the Micro-Air made a dramatic difference, but it wasn't until the latest firmware that the UPS's stopped chirping. A lot of folks have had issues, but I replaced 5 5KW PowerMir units that fell over every time the HVAC turned on, with two of these, and I've never looked back. i'm sure they will have a hardware v2 at some point, but you could definitely do much worse than the 18kpv. i wonder how well the 6000's would do in parallel starting the HVAC.

 

[murmeister]

Don't get me wrong. I really like the 18Kpv. When it's working, it's amazing - albeit somewhat loud. When it doesn't work right, my anxiety level rises and SWMBO starts asking questions for which I have no answers. If things hadn't already been working, I'd still be in "configuration" mode and would tinker with settings until I got things just right. Having JUST said "Ahh, it's nice to have everything working like it should", after running the generator tests, we started getting the PV faults the very next day. I know, I know ... I should have just kept my mouth shut. I invited the karma demons to come visit my inverter with the firmware update.

All in all, the system *IS* a beast. I expect it will only get better and better. I'm just ready for a little break in the Solar Drama and would like to focus on the tons of other projects I have lined up on my property.

 

[Warden]

Don't get me wrong. I really like the 18Kpv. When it's working, it's amazing - albeit somewhat loud. When it doesn't work right, my anxiety level rises and SWMBO starts asking questions for which I have no answers. If things hadn't already been working, I'd still be in "configuration" mode and would tinker with settings until I got things just right. Having JUST said "Ahh, it's nice to have everything working like it should", after running the generator tests, we started getting the PV faults the very next day. I know, I know ... I should have just kept my mouth shut. I invited the karma demons to come visit my inverter with the firmware update.

All in all, the system *IS* a beast. I expect it will only get better and better. I'm just ready for a little break in the Solar Drama and would like to focus on the tons of other projects I have lined up on my property.

Haha this is exactly where I'm at. Been having all kinds of AC board issues with Outback system lately and was hoping that purchasing this would get me in that relaxed state but I don't have that warm fuzzy after reading this post and a couple of others.

 

[ksmithaz1]

RE: Loud. I'm not sure what you were expecting. I doubt there is anything quieter out there with the same specs. I also don't have mine in my living room. From the laundry room (closest to the utility room they are in) I can hear them if they are really cranked and I'm being quiet. Personally I think the 18kpv is astonishingly quiet.

For a short term solution the chargeverter is hard to beat. I bought one for this very reason, because the other AIO's I had wouldn't do this either. Simple enough to let the 18K turn on the genny and dump the output to the CV setting it just under the optimal output of the genny. Couple hundred dollars is not much considering what you've already spent, and it's actually a bit more flexible.

If you actually have grid this would seem to be a very small concern. I'm running my stuff like I'm off-grid behind an ATS, when the batteries give out I just flip over. Grid's generally a helluva lot cheaper than a generator.

 

[Quattrohead]

I am on firmware 1818 and it has been solid for me. There are a couple of settings options that could be changed, they are not as obvious as they seem, mine is set for full off grid mode and to charge batteries last from PV. I do still have grid connected though and it will take it if the battery is really low or the inverter is genuinely overloaded.