Passing inspection with mix-and-match components

[etuini]

We put in a 11.7kwh solar array (Sunpower) a couple of years ago. At the time, we skipped storage because our installer only worked with powerwalls and wanted $20k per powerwall. We had a great sell-back plan the first year and never actually had a bill. Fast forward a couple of years and our sell-back options have gotten progressively worse. So we'd like to add grid-tied storage.

We're planning to order the components and hire an electrician to do the install and pull any permits we need. At the moment, I'm considering an EG4 18K inverter with PYTES v5 batteries in a V-Box. The inverter and batteries have various certifications. However, I don't see any mention of the EG4 with the PYTES batteries. PYTES did announce that their batteries were UL listed with Sol Ark inverters. (We could switch to a Sol Ark, but that raises the cost without a difference in performance.) That then made me wonder if other combinations would need to be UL listed. Does anyone have experience with this? I.e. needing the individual components and the combination to have the various certifications?

Thanks.

Brandon

 

[darrell2002]

Where are you located? Currently, in CA if you want to get permitted you can only use EG4 batteries with the 18kpv. Other states have different rules.

 

[etuini]

I'm in Houston. Most of the info I can find is geared towards panels and occasionally inverters, but I've yet to see anything to mentions how the systems are packaged.

 

[Brucey]

We put in a 11.7kwh solar array (Sunpower) a couple of years ago. At the time, we skipped storage because our installer only worked with powerwalls and wanted $20k per powerwall. We had a great sell-back plan the first year and never actually had a bill. Fast forward a couple of years and our sell-back options have gotten progressively worse. So we'd like to add grid-tied storage.

We're planning to order the components and hire an electrician to do the install and pull any permits we need. At the moment, I'm considering an EG4 18K inverter with PYTES v5 batteries in a V-Box. The inverter and batteries have various certifications. However, I don't see any mention of the EG4 with the PYTES batteries. PYTES did announce that their batteries were UL listed with Sol Ark inverters. (We could switch to a Sol Ark, but that raises the cost without a difference in performance.) That then made me wonder if other combinations would need to be UL listed. Does anyone have experience with this? I.e. needing the individual components and the combination to have the various certifications?

Thanks.

Brandon

Solark is known to be solid with the 15k. The eg18kpv is still evolving firmware wise.

 

[Hedges]

SunPower - what model inverter?

 

[etuini]

SunPower - what model inverter?

We don't have storage at the moment, just the panels. Each of which has a SunPower microinverter. Is that what you mean?

 

[seneysolar]

Yes, UL 1741 listed components are a requirement if you want to be grid interactive

 

[Hedges]

Oh, microinverter.
(Some SunPower systems used rebranded SMA string inverters.)

Whatever battery inverter is sold to go with those microinverters (if any) would be one option.
Do they support Rule-21 frequency-watts? If so, likely any battery inverter supporting AC coupling would work.

What you want is a battery inverter that supports zero/minimal export, and/or stores power to export during hours when backfeed earns high credit.

Separately, decide if you want battery backup for some/all loads when grid is down.
Large loads like A/C have high starting surge that inverter would have to support.

Hybrids like you're considering may do what you want.
SolArk, last I heard, didn't AC couple so cleanly unless it had more watts of DC coupled PV. (that's for grid-down.)

Tesla Powerwall should be able to store from PV, supply local loads.
SMA Sunny Boy Storage did, but now discontinued (and required expensive battery)

There are several other inverters for AC coupling including Schneider and Outback.

The key is using CT to measure export and charging/discharging to optimize self-consumption especially on-peak and try to import only off-peak.

 

[wheisenburg]

We don't have storage at the moment, just the panels. Each of which has a SunPower microinverter. Is that what you mean?

Getting a system that uses AC coupling to work while on grid is fairly straight forward. However with these off brand micro inverters, it is going to be challenging to get the system to work when the grid is down. Maybe you don't care about this, but most of these AC coupled systems have all kinds of design constraints concerning the ratios of batteries to PV watts. Inverter power to PV watts. Then there is the frequency shifting required to get the AC coupled PV to ramp down it power production. Do you know if your micro inverters even support that?

Your average electrician probably isn't going to be familiar with setting up an AC coupled solar system.