• Have you tried out dark mode?! Scroll to the bottom of any page to find a sun or moon icon to turn dark mode on or off!

diy solar

diy solar

EG4 18kPV vs 12000XP vs FlexBOSS21

Do you know or did you ever consider combining the FB21 & 12000XP together and configure in parallel? I'm considering mixing these two.
The XP inverters are not compatible with Gridboss as regular inverters

You may be able to look into whether they implemented support for using the XP inverters as generators feeding into either GEN port of a Gridboss or GEN port of an inverter that has a GEN input. I don't believe FB21 has a GEN input.

Also, if you are in the Bay Area the XP inverters aren't compatible with California building code. You're going to have to deal with the planning and consequences of hiding them.
 
My issue with the 12000xp has been that it's software pretty lacking (android app issues and Wi-Fi dongle issues).
That's good to know because I was about to settle on the 12000XP. Can you share in details what these issues were? Are they resolvable? Has EG4 ack'ed them and said a fix is on the way or went silent? Thanks @ddxv
 
Also, if you are in the Bay Area the XP inverters aren't compatible with California building code. You're going to have to deal with the planning and consequences of hiding them.
12000XP is not approved in Bay Area? However, the certifications of both FB21 and 12000XP are identical. Can you share more details here? Mounting solution is the same.


The XP inverters are not compatible with Gridboss as regular inverters

You may be able to look into whether they implemented support for using the XP inverters as generators feeding into either GEN port of a Gridboss or GEN port of an inverter that has a GEN input. I don't believe FB21 has a GEN input.
Wasn't using with GB; Goal is combine FB21 and 12000XP (no GridBoss needed). I've also sized my system to 14.4kW and 64kWh battery and GEN port isn't as useful to me anymore. I'd charge batteries thorugh a generator + Chargeverter.

NOTE: Don't know for sure yet, but I combined FB21 & 12000XP in parallel config (primary/secondary), I'd end up derating the FB21 from 66A to 50A (something EG4 told me about combining the 18kPV and 12kPV; not sure if it applies to FB21 and 12000XP though, but I guess it will likely apply).

_____

Still wondering (and possibly miffed) about the 12000XP and Bay Area comment! Please do share more details.
 
12000XP is not approved in Bay Area? However, the certifications of both FB21 and 12000XP are identical. Can you share more details here? Mounting solution is the same.
Check your ontology for UL certifications for inverters :-)

UL9540 is required in California. Unless something huge has changed with EG4 product segmentation or I just misunderstood it, 12000XP is 1741 only

It has to do with tier of UL testing, mounting might be some input to it, but it doesn't really matter to you because you only care about the end certifications it carries.

Actually I'm not sure FB21 and GridBoss are CEC and UL9540 yet, but I expect them to be soon, while the 6000XP series was to my mind segmented away from that.

Wasn't using with GB; Goal is combine FB21 and 12000XP (no GridBoss needed). I've also sized my system to 14.4kW and 64kWh battery and GEN port isn't as useful to me anymore. I'd charge batteries thorugh a generator + Chargeverter.
There's no GEN port on FB21 so I don't see how that would work. I welcome you to tag EG4 or a current 18kpv/FB21 owner though, I haven't bought/installed one yet.

Why do you need both hybrid (FB21) and extra off-grid capacity? To me, hybrid is enough for someone with grid. In terms of maximizing ROI. There are some edge cases though, if you can walk through the reasoning that will be good. Usually people add parallel inverters to have more grid-down capacity to handle big loads.
NOTE: Don't know for sure yet, but I combined FB21 & 12000XP in parallel config (primary/secondary), I'd end up derating the FB21 from 66A to 50A (something EG4 told me about combining the 18kPV and 12kPV; not sure if it applies to FB21 and 12000XP though, but I guess it will likely apply).
This is probably the 18kpv GEN port thing, treating the 6000XP or 12000XP as a generator to boost. But, FB21 does not have a GEN port. If you want to use a generator or AC coupling of additional solar or whatever, you will need GridBoss (since those go into a GEN port, and the FB21 doesn't have a Gen port, delegating this to the GridBoss)

1736747145830.png
1736747180402.png
 
I don't know much about the 18k but have the flexboss21 and gridboss, but connected to the grid. Not sure about the 18k but the gridboss will start your generator at conditions that can be programmed, including time, battery charge, etc.
@alvitdk

Which generator do you use for this? I assume it has to know how to communicate with the GB to initiate a remote start function. Thanks. 🙏
 
I believe the 12000xp has an EPS on/off switch. If you installed 2 units, and it was the dark time of year, you could turn it off on one unit. Or turn the whole thing off if no panels are hooked to the second unit. This should save a lot of idle draw.

I have an 18kpv but don't have grid hooked to it. The 12000xp wasn't around then. If I was doing it now I would get either the flex boss or 12000xp. The FB is more "flexible" like the 18kpv as far as pushing the loads temporarily past 12000watts. For me that only comes into play when somebody turns on the dryer without checking on the range and WH etc. Depending on how you set up your appliances this shouldn't be an issue since you are starting with the limited pv energy in mind from the get go.

I wish I could trade my 18kpv for 2 12000xps. Redundancy is part of it. Ability to add a ton more pv in the future is another. This may sound silly but honestly not having to remember which settings are for grid tie, off grid or both would be so much better. All the settings pertain to off grid on the XP. The real question mark to me is the non sealed case.
 
Actually I'm not sure FB21 and GridBoss are CEC and UL9540 yet, but I expect them to be soon, while the 6000XP series was to my mind segmented away from that.
I can't plan "using" or "buy" by trusting "will be soon". "EG4 soon" on 12000XP FW took months and that was firmware (something they can control). I'll be checking with EG4 tomorrow on 12000XP certs. I'm happy to share what I learn.

There's no GEN port on FB21 so I don't see how that would work. I welcome you to tag EG4 or a current 18kpv/FB21 owner though, I haven't bought/installed one yet.
I am not pushing back to PGE (my policy is zero export); but I would like to pull from them as backup to my generator. I don't care for the GEN port either. I use a generator + chargeverter to charge batteries directly. My desire is for more MPPT & current capacity; it's simply a question of future expansion capacity (e.g.: more PV panels).
 
I can't plan "using" or "buy" by trusting "will be soon". "EG4 soon" on 12000XP FW took months and that was firmware (something they can control). I'll be checking with EG4 tomorrow on 12000XP certs. I'm happy to share what I learn.
18KPV is 9540 and CEC listed already and people have I believe finished PG&E connection.

I am not pushing back to PGE (my policy is zero export); but I would like to pull from them as backup to my generator. I don't care for the GEN port either. I use a generator + chargeverter to charge batteries directly. My desire is for more MPPT & current capacity; it's simply a question of future expansion capacity (e.g.: more PV panels).
OK, so you have an interconnection agreement with zero export?

The GEN port is needed for AC coupling from grid tie inverter, which is one way to do expansion.

The tricky part with expansion is (these are de jure actions, you can also choose to risk naughtiness)
  • if you DC couple anything (12000XP or an MPPT) into the battery, that will likely have to be 9540 listed to pass California building code. This is a rare listing
  • if you AC couple another grid tie inverter, and you normally operate in hybrid mode with the inverter parallel to grid, then you will need to update the interconnection agreement. Not impossible, but extra pain and cost.
  • if you do not operate parallel with PG&E, then you can AC couple another grid tie inverter without involving them
The reason I talk about AC coupling is that it legally bypasses the 9540 rules by relying on the 9540 inverter to charge the battery. And UL1741 grid tie inverters are pretty cheap
 
It is NOT possible to run GEN & power loads at the same time. It's one or the other, not both simultaneously. It will charge batteries while GEN is running though.
This doesn't make sense to me. What is the point of the GEN port if you can't power loads with it? Where else would the power from the generator go?
 
Or are you referring to the (lack of a) "GEN boost" feature? I don't expect it to power loads from the battery and boost with the generator.
 
Or are you referring to the (lack of a) "GEN boost" feature? I don't expect it to power loads from the battery and boost with the generator.
That may not be a universal customer expectation (whether or not the customer is right to think that, is a different question. I’ve hashed this out with folks multiple times).
 
This doesn't make sense to me. What is the point of the GEN port if you can't power loads with it? Where else would the power from the generator go?
I want to make sure you & I both are on the same page.

1. The 12000XP can pull power from a GEN port that it uses to power AC loads. It can't be used to charge batteries. The GEN port is used to as an AC input source for AC output. It can also use the bypass mode (when the inverter is off).

2. When Grid or Gen is active on the 12000XP, the 12000XP cannot power AC loads (120/240V) from Solar or Batteries at the same time, even if energy from such sources is present.

3. When Grid or Gen is active on the 12000XP, the 12000XP can charge batteries from Solar if energy from solar is present.

@BTOdell
I'm also miffed about this setup. This is an EG4 product level decision and has nothing to do with the cost being effective to enable such a feature or not. The additional cost would be <<$100 given the existing board level components.

Hope that clarifies things.
 
Last edited:
OK, so you have an interconnection agreement with zero export?
More details here... TLDR; I am setting up in two phases (bc PGE takes 8-9 months to approve interconnection agreements). So Phase 1 is NO interconnection agreement; just a separate LC (where no PGE connection exists) with all property loads added (inverter + battery + PV, NO GRID connection). Grid connection comes in phase 2... essentially, they can take their sweet time to say "YES".

I'll be checking with EG4 tomorrow on 12000XP certs. I'm happy to share what I learn.
12000XP will not get a CEC Phase I, II, III cert according to EG4. So the AC Input GRID port on the 12000XP is basically useless in California.
 
Last edited:
The 12000XP can pull power from a GEN port that it uses to power AC loads. It can't be used to charge batteries.
That's really unfortunate that the 12000XP can't use the GRID or GEN port to charge batteries. I think I'm going to deep dive into the manual for the 12000XP just to convince myself.

If the 12000XP can't charge batteries from the GEN port, then I'll need to go with the FB21 or 18kPV. During long Alaska winters, I need to be able to bootstrap up my electrical system and get the batteries healthy if they've been drained.

EDIT:

After a quick look at the manual, I've already spotted some information that contradicts your claims:
1736812534643.png
"... but can utilize grid power for battery charging"

And one of the operating modes shows that it can accept PV and AC at the same time to charge batteries:
1736812771146.png
The screenshot diagram also seems to show the AC input is also being used to power the loads (the house icon). Although it doesn't explicitly say that in the text description (on the right).


I think the conclusion is that the 12000XP doesn't have a "GEN boost" feature where both the inverter and the AC input power AC loads at the same time. This would require more advanced electronics in the 12000XP in order to synchronize the AC waveform of the inverter with the generator's waveform.
 
Last edited:
I think the conclusion is that the 12000XP doesn't have a "GEN boost" feature where both the inverter and the AC input power AC loads at the same time. This would require more advanced electronics in the 12000XP in order to synchronize the AC waveform of the inverter with the generator's waveform.

There's various ways it can work counterintuitively. I've mentioned on other threads (maybe one of yours even) that there are different flavors within Gen Boost... For instance if the inverter is only boosting, vs reversing between charging and boosting. The latter may not be that hard if the generator is good enough to catch the momentary surge without resetting.

If you have PV, the reversing is easier and requires fewer power paths to be reconfigured (IE, charging -> discharging requires flipping the DC-DC converter for the 48V battery on top of flipping the charger/inverter. Presumably the MPPT doesn't need to be flipped, and is already at an amenable voltage for the inverter to pull. I'm extrapolating this from some system block diagrams and the fact that some hybrids have a recommended amount of DC for stable AC coupling operation)

A very easy mode to implement, is if the generator is massive, and can support both charging and loads.
 
FWIW I skimmed 6000XP manual and it does mention generator boost mode. Along with a mode where it only charges + passes through (IE, the easiest mode)

And you can find gen boost in 12000XP manual if you ctrl-f for "boost"
 
I can confirm (asked EG4 tech after I was confused and @green-river and others suggested I check): It is NOT possible to run GEN & power loads at the same time. It's one or the other, not both simultaneously. It will charge batteries while GEN is running though.

The manual section 7.3 is very ambiguous. It says "Grid or PV and Batteries" and should add the phrase, "but not both at the same time".

I've been using it to run AC loads and charge at the same time? Not sure if I'm misunderstanding, as I am fully off grid. But we have been using the gen boost feature for a week or two with no issues.

The gen boost feature requires updating the firmware.
 
That's good to know because I was about to settle on the 12000XP. Can you share in details what these issues were? Are they resolvable? Has EG4 ack'ed them and said a fix is on the way or went silent? Thanks @ddxv
The software issues I had:

Firmware doesn't allow charging above 59v which makes this impossible to equalize with older 48v lead acid batteries. They cited NEC for the reason.

The Android app 100% does not yet support it yet. No idea on the timeline. The iOS app works.

The WiFi dongle broke when I updated firmware but they got me a new one within a week. In the meantime the local connect iPhone still worked.
 
That's really unfortunate that the 12000XP can't use the GRID or GEN port to charge batteries. I think I'm going to deep dive into the manual for the 12000XP just to convince myself.

If the 12000XP can't charge batteries from the GEN port, then I'll need to go with the FB21 or 18kPV. During long Alaska winters, I need to be able to bootstrap up my electrical system and get the batteries healthy if they've been drained.

EDIT:

After a quick look at the manual, I've already spotted some information that contradicts your claims:
View attachment 269950
"... but can utilize grid power for battery charging"

And one of the operating modes shows that it can accept PV and AC at the same time to charge batteries:
View attachment 269951
The screenshot diagram also seems to show the AC input is also being used to power the loads (the house icon). Although it doesn't explicitly say that in the text description (on the right).


I think the conclusion is that the 12000XP doesn't have a "GEN boost" feature where both the inverter and the AC input power AC loads at the same time. This would require more advanced electronics in the 12000XP in order to synchronize the AC waveform of the inverter with the generator's waveform.
Hi @BTOdell @ddxv

I apologize 😥 & I'm happier for apologizing... :). I originally checked with EG4 S2 techs (EG4 owns Signature Solar). I did call back to ask EG4 tech teams (spoke to one directly) & I stand corrected. From this point on, I'll read the entire manual line by line to understand what is/isn't possible and not rely on Signature Solar's Tech Team's responses. BTW, I did start reading already.

There are various modes that the 12000XP can operate (working modes section (11.3) of the manual). For future readers, those modes indicate that the 12000XP can do any of the things that are expected, including having ANY AC INPUT (GRID or GEN) power both LOADS AS WELL AS Charge BATTERIES at the same time. The EG4 (on the EG4 side of the company, not Signature Solar) indicated that when connected in this configuration, the electronics will prioritize the LOADS first and then any excess will go to the batteries, even if the low threshold set on the Charge Tab (see section 11.7 of the manual, Page 44 (Page 47 of the PDF)) is met.

@BTOdell; I also found a note re: the Gen Boost feature

Re: Gen Boost

After starting to read the manual in detail, this inverter is supposedly capable of "Gen Boost" (Section 7.5, see screenshot (page 20 manual, page 23 of PDF). GEN BOOST is available when grid is unavailable. The generator & batteries can work together to support the loads. So GEN BOOST for AC Input to power AC loads is possible through the generator, supposedly. There is an assumption of THD <3% in the paragraph that follows the one excerpted below. Hope this helps.

1736872621447.png
 
Last edited:
The software issues I had:

Firmware doesn't allow charging above 59v which makes this impossible to equalize with older 48v lead acid batteries. They cited NEC for the reason.

The Android app 100% does not yet support it yet. No idea on the timeline. The iOS app works.

The WiFi dongle broke when I updated firmware but they got me a new one within a week. In the meantime the local connect iPhone still worked.
Thanks @ddxv. Have you tried pulling the data off the CAN BUS directly & putting it into a database? Or are you relying on their own remote UI software?
 
The generator & batteries can work together to support the loads. So GEN BOOST for AC Input to power AC loads is possible through the generator, supposedly. There is an assumption of THD <3% in the paragraph that follows the one excerpted below. Hope this helps.

View attachment 270050

Yes, this works 100%. We even ran it a few times off a portable generator with >10% THD with no issues, though we've since bought the chargeverter as we read the THD being high could potentially damage the inverter.
 
Firmware doesn't allow charging above 59v which makes this impossible to equalize with older 48v lead acid batteries. They cited NEC for the reason.
59 volts is 2.46 volts per cell which is way high for lead acid. You shouldn't need to go that high. I'd recommend you stay at 2.4 volts per cell or less (57.6 volts). High voltages lead to out gassing. Lead acid will equalize with long term float charging at about 2.30 volts per cell.

The "60 volt" limit is a general limit for "safe" low voltages. This is why Power over Ethernet stops at 57 volts, for example, and why you don't see 96 volt inverter battery systems (once you go that high, might as well be ~400 volts for efficiency).

Mike C.
 
FWIW I skimmed 6000XP manual and it does mention generator boost mode. Along with a mode where it only charges + passes through (IE, the easiest mode)

And you can find gen boost in 12000XP manual if you ctrl-f for "boost"

Actually I have the EU version of the 6000xp tested here, I can verify that the gen port could be mixed with the battery to power the load abd you can select from 500w to 7500w of gen input power..
 

diy solar

diy solar
Back
Top