Outback to Growatt system upgrade - Keep using Outback and other ?

viccooper

Solar Enthusiast
Joined
Jul 7, 2021
Messages
17
I have been living off-grid in Big Sur, CA, USA for 16 years and I am running on
  • a pair of Outback 3600 watt VFX3648 inverters,
  • an Outback MX60 MPPT solar CC,
  • 20 kW of LifePO4 (16s 400 Amp CATL cells). This bank is 5 years old.
  • 20 kWh 80 amp 240V AC propane genset
  • 4 kW of solar panels.
Everything works great but my loads just keep growing. And with the price and carbon impact of propane I would like to convert more heating loads away from propane and on to solar electricity and use my generator less. Oh, and I have a Tesla Model Y that I would like to charge anytime I have extra solar (otherwise I charge it at super chargers).
I have been watching a ton of Youtube videos by Will and others to update my knowledge and so far I have purchased
  • 12 kWh of used panels from Santan along with
  • 2x Growatt 5000US All-in-Ones from Signature Solar,
  • a Growatt SC 4880 MPPT CC (for the existing panels) from Signature Solar,
  • 4x EG4-LL 5.12 kWh batteries (20 kWh total) from Signature Solar,
  • SolarEdge autotransformer from Signature Solar
I'm aware of the safety concerns people are raising about Growatt 5000ES/US being used on grid in North America and the concerns people have with using an autotransformer to supply 120V AC. I believe I can (with a little help from SS and others) set all this up safely but I would love some input on this along with my overall system design.

For example, I currently have two 240 V water pumps (one for lift and the other for pressure) along with a 240 V sewage pump. Most of the new loads I want to add to the system are 240 V AC. I want to add the Tesla charger, one or two mini-splits, a welder (and other shop equipment) and heat pump water heaters (I have two small (1000 sq ft) houses on the property). I basically want to keep adding to my capacity until I can run as much a possible off of electricity.

Originally I was just going to sell or donate my Outback equipment but those things seem like tanks compared to the Growatts. Does it make sense to keep using the Outback inverters to supply 120V (240V with both) to my existing AC panels and subpanels while moving the pumps and setting up the new panels for 240V loads on the Growatts? I would keep the AC side of Growatts and the AC side of the Outback inverters separate.

I understand that I would need to sort out how to setup the generator. Only one system could control the two-wire remote start at a time. I also know from experience that it is very useful to have the ability to take down parts of the system for maintenance while running on the other parts so I need to consider how to switch from one system (Outback or Growatt) when needed or run them both at the same time. I need to carefully configure the AC battery charging so I don't exceed the .5C charge rate of the batteries.

I am still working out how to wire up the batteries to a bus bar with fuses and a shunt (for SOC monitoring). I am considering the Victron Lynx for this but it is quite pricey.

I have a system design diagram that you can look at. It is a work in progress and you will see some circuits that are not complete and I haven't sorted out the AC grounding yet but I think it is far enough along to start asking for feedback.

Thanks!

Vic Cooper
 
Last edited:

newbostonconst

Solar Addict
Joined
Sep 24, 2019
Messages
879
Very nice drawing....jealous. I thing you have the knowledge to make what ever work....do you plan on taking everything apart or just keep adding on? At some point a complete redue might be needed....

Good Luck
 

viccooper

Solar Enthusiast
Joined
Jul 7, 2021
Messages
17
Very nice drawing....jealous. I thing you have the knowledge to make what ever work....do you plan on taking everything apart or just keep adding on? At some point a complete redue might be needed....

Good Luck
Thanks! That drawing has taken me so much time it's ridiculous but it has been a good way to think it all through. The switchover will be tricky. It's sort of like replacing an engine in mid-air. I need to keep everything (lights, refrigerator etc..) working during the upgrade. My plan is to get the new Growatts and EG4 batteries up a running then run on that system (so I will need to get the autotransformer working for 120 loads). Then I need to do some work on the 400 amp 16s battery bank. I want to top balance it and I would like to replace the BMS. The Orion Jr BMS is ok but I don't think it will do low temp monitoring and I would like to have a way to monitor and control the BMS remotely. I like the DIYBMS but I'm not sure all the components are available.
I also need to get it charged up to a matching voltage with the EG4s before connecting them.
I think one thing that people new to off-grid solar don't fully appreciate is how to anticipate how their system will evolve and change over time. I love the challenge but it is very different than just having the utility company keeping your lights on.
 

newbostonconst

Solar Addict
Joined
Sep 24, 2019
Messages
879
Have you looked at the Outback GS8048 and GS4048? They might be cheaper and more effective then the growatts....FYI you don't have to use the lower panel if you have fuses and breakers all ready. They AC and DC couple is you understand that....With the firmware upgrade they will throttle back the new micro inverters and inverters that are capable so you can add on latter to the solar side. The outback is also transformer based and not transistor based so it has a lot more balls to start loads. And it is UL listed.
 

Ozark Tinkering

Solar Addict
Joined
Dec 23, 2021
Messages
591
I have been living off-grid in Big Sur, CA, USA for 16 years and I am running on
  • a pair of Outback 3600 watt VFX3648 inverters,
  • an Outback MX60 MPPT solar CC,
  • 20 kW of LifePO4 (16s 400 Amp CATL cells). This bank is 5 years old.
  • 20 kWh 80 amp 240V AC propane genset
  • 4 kW of solar panels.
Everything works great but my loads just keep growing. And with the price and carbon impact of propane I would like to convert more heating loads away from propane and on to solar electricity and use my generator less. Oh, and I have a Tesla Model Y that I would like to charge anytime I have extra solar (otherwise I charge it at super chargers).
I have been watching a ton of Youtube videos by Will and others to update my knowledge and so far I have purchased
  • 12 kWh of used panels from Santan along with
  • 2x Growatt 5000US All-in-Ones from Signature Solar,
  • a Growatt SC 4880 MPPT CC (for the existing panels) from Signature Solar,
  • 4x EG4-LL 5.12 kWh batteries (20 kWh total) from Signature Solar,
  • SolarEdge autotransformer from Signature Solar
I'm aware of the safety concerns people are raising about Growatt 5000ES/US being used on grid in North America and the concerns people have with using an autotransformer to supply 120V AC. I believe I can (with a little help from SS and others) set all this up safely but I would love some input on this along with my overall system design.

For example, I currently have two 240 V water pumps (one for lift and the other for pressure) along with a 240 V sewage pump. Most of the new loads I want to add to the system are 240 V AC. I want to add the Tesla charger, one or two mini-splits, a welder (and other shop equipment) and heat pump water heaters (I have two small (1000 sq ft) houses on the property). I basically want to keep adding to my capacity until I can run as much a possible off of electricity.

Originally I was just going to sell or donate my Outback equipment but those things seem like tanks compared to the Growatts. Does it make sense to keep using the Outback inverters to supply 120V (240V with both) to my existing AC panels and subpanels while moving the pumps and setting up the new panels for 240V loads on the Growatts? I would keep the AC side of Growatts and the AC side of the Outback inverters separate.

I understand that I would need to sort out how to setup the generator. Only one system could control the two-wire remote start at a time. I also know from experience that it is very useful to have the ability to take down parts of the system for maintenance while running on the other parts so I need to consider how to switch from one system (Outback or Growatt) when needed or run them both at the same time. I need to carefully configure the AC battery charging so I don't exceed the .5C charge rate of the batteries.

I am still working out how to wire up the batteries to a bus bar with fuses and a shunt (for SOC monitoring). I am considering the Victron Lynx for this but it is quite pricey.

I have a system design diagram that you can look at. It is a work in progress and you will see some circuits that are not complete and I haven't sorted out the AC grounding yet but I think it is far enough along to start asking for feedback.

Thanks!

Vic Cooper
Hi Vic, I like your diagram! What program do I need to do that for myself?
Thanks!
 

viccooper

Solar Enthusiast
Joined
Jul 7, 2021
Messages
17
Have you looked at the Outback GS8048 and GS4048? They might be cheaper and more effective then the growatts....FYI you don't have to use the lower panel if you have fuses and breakers all ready. They AC and DC couple is you understand that....With the firmware upgrade they will throttle back the new micro inverters and inverters that are capable so you can add on latter to the solar side. The outback is also transformer based and not transistor based so it has a lot more balls to start loads. And it is UL listed.
More effective - yes. Cheaper? No. The Growatts were $900 each instead of $4000 for the GS8048. I have a lot of respect for Outback. They are rock solid but I don't think they are going to survive if they can't compete with Chinese manufacturers like Growatt.
I do think I have too many panels, fuses and breakers. It's turns into a hair ball pretty fast. Once I settle on all the major components then I will trim away the fat.
 

viccooper

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Joined
Jul 7, 2021
Messages
17
Hi Vic, I like your diagram! What program do I need to do that for myself?
Thanks!
It's called Lucid chart. I used to use Visio a lot but this is cheaper and does everything I need. Plus the online sharing is better. If you have a login then you can add comments to my drawing.
Also happy to share a copy if you want to use any of the shapes. They are nothing fancy but it does save some time if you don't have to start from scratch.
 

Ozark Tinkering

Solar Addict
Joined
Dec 23, 2021
Messages
591
It's called Lucid chart. I used to use Visio a lot but this is cheaper and does everything I need. Plus the online sharing is better. If you have a login then you can add comments to my drawing.
Also happy to share a copy if you want to use any of the shapes. They are nothing fancy but it does save some time if you don't have to start from scratch.
Thanks, Vic! Which level of the app did you purchase?
 

viccooper

Solar Enthusiast
Joined
Jul 7, 2021
Messages
17
I don't have the time at the moment to go over the details, but I'm just going to say this...

Outback UPGRADE to Growatt.

That's the wrong word. "Downgrade" is more appropriate.
Yeah, could be read that way. The upgrade is in system capacity not necessarily the quality of components. The standard I am going for is "good enough, safe enough."
 

viccooper

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Joined
Jul 7, 2021
Messages
17
Yeah, could be read that way. The upgrade is in system capacity not necessarily the quality of components. The standard I am going for is "good enough, safe enough."
Thanks, Vic! Which level of the app did you purchase?
Individual. $8 per month billed yearly. I also use it in my day job (telecommunications systems architect) which helps me justify the cost
 

robby

Photon Vampire
Joined
May 1, 2021
Messages
1,798
It's called Lucid chart. I used to use Visio a lot but this is cheaper and does everything I need. Plus the online sharing is better. If you have a login then you can add comments to my drawing.
Also happy to share a copy if you want to use any of the shapes. They are nothing fancy but it does save some time if you don't have to start from scratch.
Love your Schematic.
I would not use the Growatts, this issue they are having is only going to get worst and while it may be possible that Growatt fixes the issue in newer models I kind of doubt it. There is not enough Growatt sales in the USA for them to bother going heavily into making it work properly with Split Phase.

BTW would love to get a copy of your Schematic to use elements of it.
 

Ozark Tinkering

Solar Addict
Joined
Dec 23, 2021
Messages
591
@viccooper have you ever put a watthour meter on your system to see what your daily/monthly usage has been in the past? Someone here used a 4-1 rule when it comes to daily average output on a solar panel. so if you have 12kw worth of solar panels you can generally figure the system will produce about 48kwh per day. I'm finding that to be pretty close to what my grid-tie system produces, 4-1.
From my point of view you have just about enough in solar panels it would provide north of 80% of my power needs which are pretty basic. So it seems to me you will need to keep your original setup and maybe divide your loads between them. I'm just not sure 20kwh of battery would get me through from happy hour to morning coffee?
 

viccooper

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Joined
Jul 7, 2021
Messages
17
Not sure if this will work but I created a template from my Lucidchart diagram and then created this link. I think this should allow anyone to create their own copy of the drawing. There does not seem to be a way to just export the drawing as a file unless I save it as a Visio drawing first. Let me know if this works
 

viccooper

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Joined
Jul 7, 2021
Messages
17
Hope you're safe from the fires there.
469470EC-1859-4FCE-8FBB-65734C9D3C1D_1_105_c.jpeg

Thanks for asking. This was the view from our house Friday night within one hour of the fire starting. Luckily the wind was blowing towards the ocean and away from the house. But it was super scary how fast it happened and just crazy to have a fire in January. We had heavy rains just before Christmas which probably help a lot but the area the fire burned in had not burned in over 70 years.
AEBF26B2-11CD-4532-8AD0-D8A04FEC03E2.jpeg
Today the fire seems to be fully contained and we are hoping they will allow people who evacuated to return tomorrow. Our caretakers and neighbors took these pictures. We happened to be out of town since January 15th
 

viccooper

Solar Enthusiast
Joined
Jul 7, 2021
Messages
17
@viccooper have you ever put a watthour meter on your system to see what your daily/monthly usage has been in the past? Someone here used a 4-1 rule when it comes to daily average output on a solar panel. so if you have 12kw worth of solar panels you can generally figure the system will produce about 48kwh per day. I'm finding that to be pretty close to what my grid-tie system produces, 4-1.
From my point of view you have just about enough in solar panels it would provide north of 80% of my power needs which are pretty basic. So it seems to me you will need to keep your original setup and maybe divide your loads between them. I'm just not sure 20kwh of battery would get me through from happy hour to morning coffee?
Daily usage is in the 10 to 20 kWh range but we now have caretakers living in the second house and we do not generate enough power to keep the water tanks full and are having to spend too much on propane for the generator. It takes thousands of dollars to fill our two 500 gallon propane tanks and I would rather spend that money on solar.
Plus I want to add some mini-splits for AC in the summer and eventually heat water with electricity. Oh, and charge my Tesla :cool:
 

Ozark Tinkering

Solar Addict
Joined
Dec 23, 2021
Messages
591
Not sure if this will work but I created a template from my Lucidchart diagram and then created this link. I think this should allow anyone to create their own copy of the drawing. There does not seem to be a way to just export the drawing as a file unless I save it as a Visio drawing first. Let me know if this works
Thanks! Looks like it'll work fine. It'll probably take me a month of mornings to figure out how to use this but it'd sure be nice to put a scheme together for my home. My grandsons might appreciate it later? So when it's complete, you can download it as a file?
 

robby

Photon Vampire
Joined
May 1, 2021
Messages
1,798
Not sure if this will work but I created a template from my Lucidchart diagram and then created this link. I think this should allow anyone to create their own copy of the drawing. There does not seem to be a way to just export the drawing as a file unless I save it as a Visio drawing first. Let me know if this works
That probably not going to work for me as I would then have to learn to use their tools. I am already fairly versed in some other software so I really just wanted to cut and paste some of your items. It's a bummer it wont let you export it as Jpeg or some other image file.
I plan on doing mine in Photoshop so that I can use different layers for DC, AC and control wires.
 

viccooper

Solar Enthusiast
Joined
Jul 7, 2021
Messages
17
That probably not going to work for me as I would then have to learn to use their tools. I am already fairly versed in some other software so I really just wanted to cut and paste some of your items. It's a bummer it wont let you export it as Jpeg or some other image file.
I plan on doing mine in Photoshop so that I can use different layers for DC, AC and control wires.
1643143016116.png
I can export it as an image if you want. But that seems to defeat the purpose which is to have smart shapes and connectors that adapt to changes in the drawing. And it does support layers so you could just look at the AC or DC side.
 
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