Looking for feedback on my choices for inverter and batteries

[Electronic]

I am looking for feedback on my project and materials I intend to use.

I have chosen the Conext SW 4048 inverter for my project.

Project description: battery backup for a town house for everything except the electric oven and the electric dryer. I do not expect to be able to add solar panels for two reasons, 1: very limited roof space due to HOA rules and we do not get much sunlight due to frequent foggy weather and a lot of trees. I intend to use 3 x 48V EG4 100Ah batteries which should give me enough capacity to in case PG&E cuts power for up to a day or so. Since no solar, I will set up the SW 4048 to charge the batteries when needed from the grid (at night when the cost is lower). I expect the SW 4048 can switchover to battery power when there is a power outage.

These facts are the main reasons for me to use SW 4048.

1. Rated at around 3800 W but can handle up to 4400 W for 30 minutes which is far more than I need
2. Idle power consumption 11 W
3. Efficiency 94%
4. Works well with EG4 48V rack mount batteries which I intend to use
5. Known for reliability
6. Can be grid tied and off grid (in case in the future I can add solar)
7. UL 1741
8. Weighs 62 lbs which I can handle by myself
9. Remote monitoring (I know additional module needed at extra cost)

Anyone here who has experience with EG4s + SW 4048? Any suggestions on these materials? I think I will order the Schneider breaker panels that have AC and DC breakers. For routing the wires from the existing sub-panel to the inverter panel I will use EMT. I think I will order a rack that houses 3 x EG4s. What else do I need?

 

[sunsurfer]

I would go SOK on the batts

 

[zanydroid]

Are you sure the SW4048 is as compatible as you think it is with PG&E and general California regulations?

Is it UL9540 listed with EG4 batteries? That is required by California residential code. You are also in a town house which, to my risk averse mentality, is not the best kind of living situation to deviate from code. Vs if you were installing in a detached home.

At best I think this would only be eligible for use as an off grid inverter with no grid assist. I don’t believe SW series has any possible ability for grid feedback so PG&E interconnection agreement is not needed. Which may be fine if you are smart at positioning your loads to stay within the surge limit.

 

[zanydroid]

I guess another possible consideration with PG&E is whether a given battery setup qualifies you into E-ELEC rate.

 

[Electronic]

I would go SOK on the batts

They are a little more expensive compared to EG4s. Can you elaborate on why you'd prefer SOK?

 

[Electronic]

Are you sure the SW4048 is as compatible as you think it is with PG&E and general California regulations?

Is it UL9540 listed with EG4 batteries? That is required by California residential code. You are also in a town house which, to my risk averse mentality, is not the best kind of living situation to deviate from code. Vs if you were installing in a detached home.

At best I think this would only be eligible for use as an off grid inverter with no grid assist. I don’t believe SW series has any possible ability for grid feedback so PG&E interconnection agreement is not needed. Which may be fine if you are smart at positioning your loads to stay within the surge limit.

Good question regarding UL9540. I thought EG4 had the relevant UL rating. I will need to look into it. If EG4 does not have the California residential rating then it is a deal breaker for me.

Why would it be off grid? It is capable of being connected to the grid (and I want to power the inverter panel from the grid when grid has power). I am not looking to provide power to the grid even if PG&E will take it and pay me enough for it. I doubt I will ever get excess power and it is not likely that I will install solar panels. The inverter will power light loads in the house and I do not expect any heavy demand surge. I am looking to keep the lights and the fridge on while PG&E is messing around figuring out how to restore power.

 

[sunsurfer]

They are a little more expensive compared to EG4s. Can you elaborate on why you'd prefer SOK?

BMS is more reliable. Everything is serviceable/replaceable.

 

[Electronic]

I guess another possible consideration with PG&E is whether a given battery setup qualifies you into E-ELEC rate.

Looking at PG&E doc on eligibility for E-ELEC I should qualify. But I do not care if not. Sick of power outages with 'unknown' reason and 'unknown' ETA on restoring power.

 

[zanydroid]

Good question regarding UL9540. I thought EG4 had the relevant UL rating. I will need to look into it. If EG4 does not have the California residential rating then it is a deal breaker for me.

You should check the CEC equipment list for hybrid/grid interactive equipment, SW4048 is not one of these.

UL9540 is a paired listing, the inverter and batteries must be tested and certified together. Moreover there’s a lot of placement rules in the residential code but these are less painful than just finding UL9540.

Why would it be off grid? It is capable of being connected to the grid (and I want to power the inverter panel from the grid when grid has power).

Yes, I understand that.

Off grid in the sense that equipment is defined. It is not grid interactive and does not do grid assist, ie it cannot and will not activate the inverter when grid connection relay is closed.

If you look around SW is categorized as off grid on the forum, with some special quirks like how it has a supported mode for connecting grid tie inverter on AC out and letting them see the grid & turn on.

 

[zanydroid]

Looking at PG&E doc on eligibility for E-ELEC I should qualify. But I do not care if not. Sick of power outages with 'unknown' reason and 'unknown' ETA on restoring power.

Ok sure, it wasn’t a major point. E-ELEC lets you save minor amounts of money if you have a lot of off peak loads or demand shift with a battery.

I actually had a power outage this week down on the peninsula, in the middle of a city. 5 hours ?. At least they finished before their estimated repair time.

 

[Cheap 4-life]

They are a little more expensive compared to EG4s. Can you elaborate on why you'd prefer SOK?

Recently seen SOK server rack batteries for $1299. Might have been current connected. Not sure

 

[zanydroid]

Another concern I have with CoNext is that while the hardware is awesome and probably literally bomb proof, it’s not clear how much development attention the product line is getting. If you don’t confirm that it does exactly what you want (preferably with some forum support), that’s kind of worrying. Not that it’s necessarily going to be better with an actively developed bleeding edge chinese inverter, but at least you can have some interaction with new stuff coming out.

I don’t know that I would buy SOK from anyone other than current connected. I don’t know which 9540 certs are in the works for SOK.

 

[Electronic]

BMS is more reliable. Everything is serviceable/replaceable.

Good to know thanks. But I think UL9540 is going to dictate what battery + inverter I can use.

 

[Electronic]

Another concern I have with CoNext is that while the hardware is awesome and probably literally bomb proof, it’s not clear how much development attention the product line is getting. If you don’t confirm that it does exactly what you want (preferably with some forum support), that’s kind of worrying. Not that it’s necessarily going to be better with an actively developed bleeding edge chinese inverter, but at least you can have some interaction with new stuff coming out.

I don’t know that I would buy SOK from anyone other than current connected. I don’t know which 9540 certs are in the works for SOK.

I read on Current Connected site that UL9540 is 'pending' for the more expensive (with displays) SOK 48BV battery.

 

[zanydroid]

check the CEC equipment list for hybrid/grid interactive equipment, SW4048 is not one of these.

Oops. Bad English. What I meant was, you might not find UL1741 inverters for off grid on that list. I don’t believe they need to be on the list for you to use the inverter independently of the grid (EG not running in parallel at the same time).

I read on Current Connected site that UL9540 is 'pending' for the more expensive (with displays) SOK 48BV battery.

If you like that battery you should reach out to them to verify which inverter they are working on.

 

[JoeHam]

I’ve been running a CSW4048 for a few years now.

The old style EG4 (GYLL), a DIY 100Ah and a couple of 50Ah Ecoworthy batteries power it. I started with 100Ah GYLL and added the rest later.

It runs a critical loads sub panel with about 7 or 8 circuits pulled from the main panel. Two refrigerators, sump pump, garage door opener, washing machine, my ham shack and at least one outlet on each floor of the house.

Runs on solar most of the year and I turn on grid backup in winter and sustained rainy days.

The 11W idle is underestimated, like practically all of my inverters.

The Schneider software is a bit clunky but the hardware is rock solid.

I did not use the pricey Schneider electric boxes. Just a breaker box from a home improvement store for the AC subpanel and separate DC rated breakers for that side of the system.

 

[Electronic]

I’ve been running a CSW4048 for a few years now.

The old style EG4 (GYLL), a DIY 100Ah and a couple of 50Ah Ecoworthy batteries power it. I started with 100Ah GYLL and added the rest later.

It runs a critical loads sub panel with about 7 or 8 circuits pulled from the main panel. Two refrigerators, sump pump, garage door opener, washing machine, my ham shack and at least one outlet on each floor of the house.

Runs on solar most of the year and I turn on grid backup in winter and sustained rainy days.

The 11W idle is underestimated, like practically all of my inverters.

The Schneider software is a bit clunky but the hardware is rock solid.

I did not use the pricey Schneider electric boxes. Just a breaker box from a home improvement store for the AC subpanel and separate DC rated breakers for that side of the system.

Yeah I can take that route as well with the breakers. I was trying to avoid issues with inspection. But all that seems moot now with needing the UL9540 certification. I cannot see that many (if any) DIY options for UL 9540 certified combinations. It seems I may have to wait until the new standard becomes more mainstream (and EG4/SOK and others get on it with a decent selection of inverters). I see Sol-Ark 15kW and Outback has UL9540 but those are an overkill for me.

 

[400bird]

I think Midnight Solar makes a breaker box that is less expensive than the Schneider ones. It's worth looking into.

 

[Electronic]

This is what Current Connected says about UL9540 for SOK 48V battery with the display. This section is out of date, it already has the UL9540A certification. The 9540 is with Sol-Ark inverters. I hope they have a suitably rated inverter in that list. So in a few months it should be available with UL9540.

 

[damo green]

Good question regarding UL9540. I thought EG4 had the relevant UL rating. I will need to look into it. If EG4 does not have the California residential rating then it is a deal breaker for me.

Why would it be off grid? It is capable of being connected to the grid (and I want to power the inverter panel from the grid when grid has power). I am not looking to provide power to the grid even if PG&E will take it and pay me enough for it. I doubt I will ever get excess power and it is not likely that I will install solar panels. The inverter will power light loads in the house and I do not expect any heavy demand surge. I am looking to keep the lights and the fridge on while PG&E is messing around figuring out how to restore power.

You need to find the UL listing docs for UL9540 2020 2nd edition for an ESS, it will list the inverter and the batteries that were tested together. Then you need to look at the CEC list. Some Ess's have this particular flavor of UL listing but are not on the CEC list yet although they could be soon. Last I checked ;None of the lower cost (solark,schenider,eg4) Ess's are on the CEC list yet... but I think soon. The Solark and Scheider have UL9540 2nd ed ESS documents, Eg4.. not yet