Second powerwall, what do I need?

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drspeakman

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I am constructing my second powerwall 100p14s, initial one up and running for 2 years without much issues. Using nine 280W rooftop solar panels and a PCM 60X charger, and inexpensive night grid power ($0.15 per KWhr) to charge up, and using a Schneider Conext 4048SW inverter. Electrician has helped me create a separate panel to power household lights, a MW oven, a computer, and a refrigerator, and it seems to power all day without issues. I use grid power between 11 pm and 7 am as it is so inexpensive.

With my second powerwall, it will also be 100p14s, so will be doubling my storage space, and will be able to add a lot more loads to the system. Am not going to try to power any 220volt appliances or air conditioners. Just the rest of the home's lights and more refrigerators and another MW oven.

My question is how to connect up and use this second wall, ie do I need another Schneider Conext 4048SW inverter and PCM 60X charger, or can I connect both powerwalls in parallel and use my current nine rooftop (maxed out) 280 watt solar panels and inexpensive nighttime grid power to charge both packs as a single 48v battery, now just with double the amperage? Would much prefer not purchasing additional inverter and charger...

Another question regards my other 45 rooftop 280W panels connected to SolarEdge Inverters, producing excess energy at times, fed back to the local power company and not reimbused. SolarEdge does allow for the use of a couple of commercially available powerwalls (Tesla and one other). Has anyone successfully connected a DIY Powerwall to one of these inverters? Asked this same question 2 years ago, and answer was no.

Appreciate any positive feedback.
 
hahah, you already created a 2nd one :p

So I'll put the comment over here as well:

quick answer is:
You can parallel solar inputs and parallel battery banks. Inverter outputs cannot be paralleled unless they are smart enough to do so. This usually requires an interconnect between them.
Otherwise, 1 inverter runs one circuit panel, the other inverter runs the another circuit panel

If using 1 inverter, then just parallel the battery banks to the input of the inverter. The inverter will only pull the amps required up to the max of its capacity. Just doubling the battery banks will not increase the inverters output amps. You would need a larger inverter, or a second one, to do this.


Lastly, it's 14s100p if you have 14 packs that have 100 cells in parallel and connected in series.
 
As @Korishan said, have to have 'synced' inverters to share the AC power produced by the individual units. Magnum and Outback inverters are a couple of commonly known inverters that can do this.

I use AIMS inverters due to price / output, but they cannot sync/share their output. The 2 separate AIMS pull from a single battery bank with each inverter's output going to its own (seperate) distribution panel and powers different circuits.
image_eaaihm.jpg


There's kind of a spectrum of price vs output range vs modular-sharing for AC pure sine wave inverters.
* AIMS makes 12,000watt inverters (as shown above) with relatively lower pricebut they don't cooperate - so its 2 seperate 12,000watts rather than shared 24,000watts which is not efficient in handling peak loads as each inverter has to handle its own circuits and can't share excess capacity.
* Magnum makes inverters that can 'share/cooperate' but they are only 4,000watts each to a max of 2 or 3 - e.g. 8,000 or12,000watts max
* You can buy 24,000watt (and higher)single unit inverters but the price and shear weight *really* goes up when you get into that range of power.
 
Korishan said:
hahah, you already created a 2nd one :p

So I'll put the comment over here as well:

quick answer is:
You can parallel solar inputs and parallel battery banks. Inverter outputs cannot be paralleled unless they are smart enough to do so. This usually requires an interconnect between them.
Otherwise, 1 inverter runs one circuit panel, the other inverter runs the another circuit panel

If using 1 inverter, then just parallel the battery banks to the input of the inverter. The inverter will only pull the amps required up to the max of its capacity. Just doubling the battery banks will not increase the inverters output amps. You would need a larger inverter, or a second one, to do this.


Lastly, it's 14s100p if you have 14 packs that have 100 cells in parallel and connected in series.

Thanks. Would really like to NOT add an additional inverter IF what I have would work, thinking that by adding this second bank of 14s100p, in parallel with the first bank, the Schneider Conext SW 4048NA Inverter would just see it as a single 48 volt battery, and the same would go for the PCM 60X solar charger.

BUT...with my current single powerwall, just did a test with the MW oven powered up and most everything else in the house powered up, and the Inverter display was showing an output of 1800 watts and 38 amps from the battery bank. The specs for this inverter are peak current output of 42 amps, and 3400 watts of continuous power output, or 4000 watts for up to 30 minutes, or 7000 watts for up to 5 minutes. Fairly close to the maximum amp output of 42, but well below the 3400 watts continuous output. Obviously, the MW oven is just an intermittent power output, but is used a lot. Link to the specs of my inverter found here: https://www.altestore.com/store/inv...next-sw-inverterchargers-p40463/#SCNCONSW4048.

Things I am not interested in powering: electric clothes dryer, pool pumps, air conditioners, and electric oven. But I would be interested in powering the remaining house lights, 3 flat panel TV's, and electrical outlets. I think this is more realistic. Will need my electrician to help me with deciding which additional breakers we take out of our main grid power panel and put into our battery load panel.

With all of the above said, probably less expensive in the long run to just bite the bullet, and invest in an additional inverter for this second powerwall. An additional Schneider Inverter like the one I have is around $1400. Of course, would be great if there were a way to utilize my SolarEdge StoreEdge 7.6 KW Inverter, but this appears unlikely with a DIY powerwall. Suggestions on less expensive name brands that will work for 120 volt systems in the USA are appreciated.
Click to expand...
 
You need a shrink ;)

Nah just hook it Up in parallel and double your battery capacity
 
Did some more research. The Schneider Conext 4048 SW Inverter I currently have is stackable, so can add another one to add an additional 4000 watts of output for 8000 watts total. Will see what my electrician thinks about it. I know he didn't enjoy the install of the first one as he needed smaller hands to get into the tight spaces to place and secure the wiring. But this would be less expensive than getting a larger 8000-10000 watt unit of a different variety and discarding my Schneider unit.
 
@drspeakman: With your reply to my last posting, I have no idea what your replies are. Place your replies "outside" of the quote tags/block, please.
 
Problem: A technical service bulletin issued from Schneider Electric in May of 2018 warns against stacking of their Conext SW units, with a persistent error message. Still waiting to hear from Schneider to let me know if this issue has been resolved. Pretty big issue as one of their selling points for my CURRENT 4048SW Inverter is that it is "expandable" by stacking a second unit to double the power output to 8 kW. It still says this in their sales literature...

When my current project is completed, I will have a total of 24 kWh storage, and do not see myself adding any additional, as I am out of space. Looking hard at the 10 kW and 12 kW AIMS Inverters as a single unit, and better but more expensive alternative and ditching my Schneider unit.
 
drspeakman said:
My question is how to connect up and use this second wall, ie do I need another Schneider Conext 4048SW inverter and PCM 60X charger, or can I connect both powerwalls in parallel and use my current nine rooftop (maxed out) 280 watt solar panels and inexpensive nighttime grid power to charge both packs as a single 48v battery, now just with double the amperage? Would much prefer not purchasing additional inverter and charger...

Another question regards my other 45 rooftop 280W panels connected to SolarEdge Inverters, producing excess energy at times, fed back to the local power company and not reimbused. SolarEdge does allow for the use of a couple of commercially available powerwalls (Tesla and one other). Has anyone successfully connected a DIY Powerwall to one of these inverters? Asked this same question 2 years ago, and answer was no.

Appreciate any positive feedback.
Click to expand...


I install SolarEdge invertersin Oklahoma. As far as I have found, you can't do a battery with their system unfortunately. I have seen it mentioned a few times in ads and whatnot but I've not found a reliable source demonstrating it. There are a couple work arounds that would allow you to charge a batter backup for your house but you'll still ultimately be in the grid and wasting some of what you could be saving.

Also, I recommend either just making your current system 14p200s or making two 100p systems separate. Or perhaps, using your new 1400 cells in some setup to charge off of your SolarEdge array's since they offer optimizer benefits that a traditional system usually doesn't.

I did find these but since we can't install battery systems in OK, I've never seen one.

https://www.solaris-shop.com/solaredge-storedge-se7600a-uss-7-6kw-hybrid-inverter/
 
OffGridInTheCity said:
As @Korishan said, have to have 'synced' inverters to share the AC power produced by the individual units. Magnum and Outback inverters are a couple of commonly known inverters that can do this.

I use AIMS inverters due to price / output, but they cannot sync/share their output. The 2 separate AIMS pull from a single battery bank with each inverter's output going to its own (seperate) distribution panel and powers different circuits.
image_eaaihm.jpg


There's kind of a spectrum of price vs output range vs modular-sharing for AC pure sine wave inverters.
* AIMS makes 12,000watt inverters (as shown above) with relatively lower pricebut they don't cooperate - so its 2 seperate 12,000watts rather than shared 24,000watts which is not efficient in handling peak loads as each inverter has to handle its own circuits and can't share excess capacity.
* Magnum makes inverters that can 'share/cooperate' but they are only 4,000watts each to a max of 2 or 3 - e.g. 8,000 or12,000watts max
* You can buy 24,000watt (and higher)single unit inverters but the price and shear weight *really* goes up when you get into that range of power.
Click to expand...
Second powerwall constructed and hung into place. Now, to make the final decision on the inverter situation. I have really been looking hard at just getting a single AIMS 12,000 watt inverter, and let it charge and discharge the battery pack as a single 48 volt pack, very cheap grid power at night, and during day with nine 280watt solar panels with a PCM 60X charger) connecting both powerwalls together in parallel, total of 24 kWh to power a single loads panel. I would just ditch the Schneider unit, maybe sell on eBay to recover some of the costs. It would just seem simpler this way. The AIMS unit is $3541 on Amazon Prime, a little more than twice what I paid for the 4,000 watt Schneider unit 2 years ago, but it is really 3 times the output. Warranty is only 2 years, and although usually don't go for extended warrarties, it is only $76 for 4 years. Probably worth the peace of mind.

The Schneider unit was very difficult to wire, unless you have tiny hands. It looks like the AIMS is much easier. Has that been your experience?
 
drspeakman said:
OffGridInTheCity said:
As @Korishan said, have to have 'synced' inverters to share the AC power produced by the individual units. Magnum and Outback inverters are a couple of commonly known inverters that can do this.

I use AIMS inverters due to price / output, but they cannot sync/share their output. The 2 separate AIMS pull from a single battery bank with each inverter's output going to its own (seperate) distribution panel and powers different circuits.
image_eaaihm.jpg


There's kind of a spectrum of price vs output range vs modular-sharing for AC pure sine wave inverters.
* AIMS makes 12,000watt inverters (as shown above) with relatively lower pricebut they don't cooperate - so its 2 seperate 12,000watts rather than shared 24,000watts which is not efficient in handling peak loads as each inverter has to handle its own circuits and can't share excess capacity.
* Magnum makes inverters that can 'share/cooperate' but they are only 4,000watts each to a max of 2 or 3 - e.g. 8,000 or12,000watts max
* You can buy 24,000watt (and higher)single unit inverters but the price and shear weight *really* goes up when you get into that range of power.
Click to expand...
Second powerwall constructed and hung into place. Now, to make the final decision on the inverter situation. I have really been looking hard at just getting a single AIMS 12,000 watt inverter, and let it charge and discharge the battery pack as a single 48 volt pack, very cheap grid power at night, and during day with nine 280watt solar panels with a PCM 60X charger) connecting both powerwalls together in parallel, total of 24 kWh to power a single loads panel. I would just ditch the Schneider unit, maybe sell on eBay to recover some of the costs. It would just seem simpler this way. The AIMS unit is $3541 on Amazon Prime, a little more than twice what I paid for the 4,000 watt Schneider unit 2 years ago, but it is really 3 times the output. Warranty is only 2 years, and although usually don't go for extended warrarties, it is only $76 for 4 years. Probably worth the peace of mind.

The Schneider unit was very difficult to wire, unless you have tiny hands. It looks like the AIMS is much easier. Has that been your experience?
Click to expand...
No problems wiring the AIMS. The conduit was the difficulty... 1st one was EMT but wised up on 2nd one and usedflexible armour :) My 1st AIMS has been in service about a 1.5yrs now - on/off each day with an average run time of 10hrs/day. The 2nd AIMS is just a month old but it did survive a 94a (20,000w 'ish) surge when my old AC compressor motor locked. So far so good - 11,432kwh produced to date.

They are HEAVY though - 174lbs. I contacted AIMS and they said it OK for them to 'lay flat' (as you see in the picture). Had to use block and tackle to get the top one stacked on the rack.

@LithiumSolar bought a used/2nd-hand 10K one and was successful ordering / replacing internal boards to revive it. So presumably there are repair options. He also did a youtube review of his showing much detail:
The 10K and 12K are pretty much identical except 12K is full ETL.
 
OffGridInTheCity said:
drspeakman said:
OffGridInTheCity said:
As @Korishan said, have to have 'synced' inverters to share the AC power produced by the individual units. Magnum and Outback inverters are a couple of commonly known inverters that can do this.

I use AIMS inverters due to price / output, but they cannot sync/share their output. The 2 separate AIMS pull from a single battery bank with each inverter's output going to its own (seperate) distribution panel and powers different circuits.
image_eaaihm.jpg


There's kind of a spectrum of price vs output range vs modular-sharing for AC pure sine wave inverters.
* AIMS makes 12,000watt inverters (as shown above) with relatively lower pricebut they don't cooperate - so its 2 seperate 12,000watts rather than shared 24,000watts which is not efficient in handling peak loads as each inverter has to handle its own circuits and can't share excess capacity.
* Magnum makes inverters that can 'share/cooperate' but they are only 4,000watts each to a max of 2 or 3 - e.g. 8,000 or12,000watts max
* You can buy 24,000watt (and higher)single unit inverters but the price and shear weight *really* goes up when you get into that range of power.
Click to expand...
Second powerwall constructed and hung into place. Now, to make the final decision on the inverter situation. I have really been looking hard at just getting a single AIMS 12,000 watt inverter, and let it charge and discharge the battery pack as a single 48 volt pack, very cheap grid power at night, and during day with nine 280watt solar panels with a PCM 60X charger) connecting both powerwalls together in parallel, total of 24 kWh to power a single loads panel. I would just ditch the Schneider unit, maybe sell on eBay to recover some of the costs. It would just seem simpler this way. The AIMS unit is $3541 on Amazon Prime, a little more than twice what I paid for the 4,000 watt Schneider unit 2 years ago, but it is really 3 times the output. Warranty is only 2 years, and although usually don't go for extended warrarties, it is only $76 for 4 years. Probably worth the peace of mind.

The Schneider unit was very difficult to wire, unless you have tiny hands. It looks like the AIMS is much easier. Has that been your experience?
Click to expand...
No problems wiring the AIMS. The conduit was the difficulty... 1st one was EMT but wised up on 2nd one and usedflexible armour :) My 1st AIMS has been in service about a 1.5yrs now - on/off each day with an average run time of 10hrs/day. The 2nd AIMS is just a month old but it did survive a 94a (20,000w 'ish) surge when my old AC compressor motor locked. So far so good - 11,432kwh produced to date.

They are HEAVY though - 174lbs. I contacted AIMS and they said it OK for them to 'lay flat' (as you see in the picture). Had to use block and tackle to get the top one stacked on the rack.

@LithiumSolar bought a used/2nd-hand 10K one and was successful ordering / replacing internal boards to revive it. So presumably there are repair options. He also did a youtube review of his showing much detail:
The 10K and 12K are pretty much identical except 12K is full ETL.
Click to expand...
The one thing I see missing in this unit is a connection for your solar DC input to charge the batteries. I guess this needs to be a separate connection from your solar charger (PCM 60X in my setup) to the battery bank. I do not have enough solar to totally charge, so I use inexpensive grid power at night. I would need it to invert 24/7 to run my loads panels. Am I missing anything here? My Schneider unit works fine, just not big enough, and it understands the solar charger that is connected to it.
 
drspeakman said:
The one thing I see missing in this unit is a connection for your solar DC input to charge the batteries. I guess this needs to be a separate connection from your solar charger (PCM 60X in my setup) to the battery bank.
Click to expand...
Yes - you would direct your PCM 60xto charge the battery bank. The AIMS has an AC input option that can charge the batteries as well. They can both charge the batteries independent of each other. However, I don't use AIMS to charge my batteries as that's not efficient - I use automatic transfer switches instead....

drspeakman said:
I do not have enough solar to totally charge, so I use inexpensive grid power at night. I would need it to invert 24/7 to run my loads panels. Am I missing anything here? My Schneider unit works fine, just not big enough, and it understands the solar charger that is connected to it.
Click to expand...
My PV power goes thru the Charge Controllers to charge thebattery bank. When the battery charges 'a bit' (e.g. reaches52v) I turn theinverter on. Thistriggers the ATS to take power from the inverter instead of the grid. When the PV power runs out and the batteryhits the cutt-off voltage (49.5v) the inverter turns off and the ATS switches back to grid.

If I'm understanding your comment above - Idon't see the point of using 'grid' to charge the batteries to just turn around and run the inverter to create AC. Instead, I just connect the grid directly (via the ATS) to the AC load and avoid the 15-20% power loss incurred by directing grid -> battery -> inverter -> AC load.

I think what this latest discussion is highlighting
- off-grid, grid-tie, hybrid - e.g. how you consume the AC power.
- There are distinct 'components' - PV Input, Charge Controller, Battery, Inverter, and ATS. These can be combinedor not - whichaffect the system design.
- Goals. Mine is: "Consume 100% of PV power produced in my off-grid system and let the grid take over once PV power is used.".

I'm assuming you're are off-grid and (similar to my own goals)you want to consume all of your PV power - which lead me to the comments above.
 
OffGridInTheCity said:
drspeakman said:
The one thing I see missing in this unit is a connection for your solar DC input to charge the batteries. I guess this needs to be a separate connection from your solar charger (PCM 60X in my setup) to the battery bank.
Click to expand...
Yes - you would direct your PCM 60xto charge the battery bank. The AIMS has an AC input option that can charge the batteries as well. They can both charge the batteries independent of each other. However, I don't use AIMS to charge my batteries as that's not efficient - I use automatic transfer switches instead....

drspeakman said:
I do not have enough solar to totally charge, so I use inexpensive grid power at night. I would need it to invert 24/7 to run my loads panels. Am I missing anything here? My Schneider unit works fine, just not big enough, and it understands the solar charger that is connected to it.
Click to expand...
My PV power goes thru the Charge Controllers to charge thebattery bank. When the battery charges 'a bit' (e.g. reaches52v) I turn theinverter on. Thistriggers the ATS to take power from the inverter instead of the grid. When the PV power runs out and the batteryhits the cutt-off voltage (49.5v) the inverter turns off and the ATS switches back to grid.

If I'm understanding your comment above - Idon't see the point of using 'grid' to charge the batteries to just turn around and run the inverter to create AC. Instead, I just connect the grid directly (via the ATS) to the AC load and avoid the 15-20% power loss incurred by directing grid -> battery -> inverter -> AC load.

I think what this latest discussion is highlighting
- off-grid, grid-tie, hybrid - e.g. how you consume the AC power.
- There are distinct 'components' - PV Input, Charge Controller, Battery, Inverter, and ATS. These can be combinedor not - whichaffect the system design.
- Goals. Mine is: "Consume 100% of PV power produced in my off-grid system and let the grid take over once PV power is used.".

I'm assuming you're are off-grid and (similar to my own goals)you want to consume all of your PV power - which lead me to the comments above.
Click to expand...
The ATS is the piece I am missing. My current Schneider inverter/charger essentially does this automatically. It is programmed to charge the batteries from the grid when low, essentially using this option only after 11 pm and before 7 am each morning, to take advantage of $0.15 per kWh grid energy, then I discharge all of that all day, and use whatever PV can do to keep up the battery charge, and with my current load panel, it never runs out. I am not using the grid during the day for this load panel, so all is coming from the battery bank...for the loads I currently have. But I have a LOT more loads to add, and that is why I have added my second powerwall of 12 kWh. The remainder of my system is a lot more PV using two SolarEdge StoreEdge inverters, but no battery connection is possible for my DIY powerwalls, only Tesla or LG. The excess PV energy is lost, goes back to the grid without reimbursement unfortunately.

At night, my Schneider unit charges the batteries, and acts as an ATS to power the loads from the grid, at least that is my understanding. If it isn't doing it efficiently, I wouldn't know it. I do know it is dirt cheap electricity from 11 am to 7 am.

Is the ATS automatic? A=automatic? I am interested in exactly the same goal as you, but I do not want to be watching the SOC and having to flip switches. I want it to be fully automatic. Set and forget. If getting an ATS and using this AIMS inverter, could accomplish my goals of having a larger system with bigger capability.

If you can direct me to some place where I can get more information about ATS, and where to purchase, that would be great.

I am also looking at the Outback Radian 8 kW hybrid inverter, and from the looks of it, no ATS is required. It has a gridzero setting which is exactly our goal here. Biggest drawback is price per kWh of the inverter. $3700 for the 8kWh Radian, or $3600 for the 12 kWh AIMS + whatever an ATS costs.
 
drspeakman said:
If you can direct me to some place where I can get more information about ATS, and where to purchase, that would be great.

I am also looking at the Outback Radian 8 kW hybrid inverter, and from the looks of it, no ATS is required. It has a gridzero setting which is exactly our goal here. Biggest drawback is price per kWh of the inverter. $3700 for the 8kWh Radian, or $3600 for the 12 kWh AIMS + whatever an ATS costs.
Click to expand...
Cool, I think the discussion is at least resulting in a sharing of ideas. I'm just not familiar with Schneider so I may be talking 'past you' rather than helping. So me just share thatin my case - I designed aroundoff-grid +ATS (automatic transfer switch) as the heart of my power consumption and I agree 100% - its all automatic!I don't have to touch a thing. In fact its cool because all I have to do work on things is turn off the inverter and grid automatically takes over - so I don't have to do anything to shut-down/work on solar subsystem. However - there are some things to consider:

* Motor surge - Some on this thread warn about ATS motor surge due to the sine wave not being synchronized when inverter switches to grid and vice versa. I handle this by a surge protected ATS and have beenrunning1.5years with several ATS(s)and over 1,000 switch-overs (twice a day)to date with no problems. I power the full range of household stuff including2 xrefrigerators (full size Frigidaire type), furnace fan, tools, hybrid hot water heater, portable heat-pump unit, microwave, AC compressor (in past), whole-house heatpump (currently), etc. I personally don't believe this is a problem for residential level motors.
* Switch-over gap - I use APC UPSs to bridge the switch-over gap for computers/TV/Coffee-pot with clock etc so they don't falter or shut-off or reset.
* Production<=Consumption -I recently added an additional 21 panels and this has pushed my spring time power production so high - I had to add extra battery to be able to consume100% of PV power produced right now. In other words, when you don't sell back to the grid you have to use it or loose it and that takes planning.

This all works for me, but I don't want to push youto go this way necessarily as there are OTHER solutions out there and I'm not by any means an overall expert. Maybe more folks can weigh in here to give you additional options.

If you decide to follow the route I'm using - I'm happy to share all details :)
 
OffGridInTheCity said:
drspeakman said:
If you can direct me to some place where I can get more information about ATS, and where to purchase, that would be great.

I am also looking at the Outback Radian 8 kW hybrid inverter, and from the looks of it, no ATS is required. It has a gridzero setting which is exactly our goal here. Biggest drawback is price per kWh of the inverter. $3700 for the 8kWh Radian, or $3600 for the 12 kWh AIMS + whatever an ATS costs.
Click to expand...
Cool, I think the discussion is at least resulting in a sharing of ideas. I'm just not familiar with Schneider so I may be talking 'past you' rather than helping. So me just share thatin my case - I designed aroundoff-grid +ATS (automatic transfer switch) as the heart of my power consumption and I agree 100% - its all automatic!I don't have to touch a thing. In fact its cool because all I have to do work on things is turn off the inverter and grid automatically takes over - so I don't have to do anything to shut-down/work on solar subsystem. However - there are some things to consider:

* Motor surge - Some on this thread warn about ATS motor surge due to the sine wave not being synchronized when inverter switches to grid and vice versa. I handle this by a surge protected ATS and have beenrunning1.5years with several ATS(s)and over 1,000 switch-overs (twice a day)to date with no problems. I power the full range of household stuff including2 xrefrigerators (full size Frigidaire type), furnace fan, tools, hybrid hot water heater, portable heat-pump unit, microwave, AC compressor (in past), whole-house heatpump (currently), etc. I personally don't believe this is a problem for residential level motors.
* Switch-over gap - I use APC UPSs to bridge the switch-over gap for computers/TV/Coffee-pot with clock etc so they don't falter or shut-off or reset.
* Production<=Consumption -I recently added an additional 21 panels and this has pushed my spring time power production so high - I had to add extra battery to be able to consume100% of PV power produced right now. In other words, when you don't sell back to the grid you have to use it or loose it and that takes planning.

This all works for me, but I don't want to push youto go this way necessarily as there are OTHER solutions out there and I'm not by any means an overall expert. Maybe more folks can weigh in here to give you additional options.

If you decide to follow the route I'm using - I'm happy to share all details :)
Click to expand...
Would love to hear the details. Your method is using what I believe is a simple inverter, not all the bells and whistles of these more expensive hybrid inverters that have other things built in (Outback Radian, Schneider Conext). And using the ATS sounds awesome. Currently, the way my electrician has wired it, when I need to work on my inverter (so far, no issues) or battery pack (yes, have had some low functioning packs over the last 2 years that I have rebuilt), the power to all of my loads goes OFF. So, I have to be ready to do things quickly to make the family happy with my "science project". And what if I am away on vacation...I want my electrician to arrange this differently, but unfortunately, he really doesn't know that much about solar, and nobody in my area DOES at this point. I am in need of a redesign. So, I am reaching out to anyone who can lay out the different possible designs and ways to do this right now, hoping someone else can chime in and describe in detail how they have done it. Certainly, I am not the only newbie here that would like to know. And certainly there are those DIYers that have done this more than once, and learned better ways of doing things. And, what about ATS's, where to read about and purchase?

I need to train my electrician. He helped me with my solar panels, and install of solar battery charger, and all inverters. He does great work and is anxious to learn.
 
>Your method is using what I believe is a simple inverter, not all the bells and whistles....
Yes.The Midnite Classic controllers (that I use)have an "AUX1" feature which allows control of external devices. This isused to turn the AIMS on at 52v and off at 49.5v (or whatever you set)thru the remote LCD port - e.g. wires 3 and 5 of simple RJ45 (internet) wire.

If you look at my build thread -https://secondlifestorage.com/showthread.php?tid=8514 The 4th post shows a Progressive Dynamics 240v@50a ATS in combination with a Pro-Tran 10-circuit Manual Transfer switchand discussion to answer @cowpen. The main panel 240v@50a circuit breakers provide the shore power side ofthe ATS and the AIMS 12,000w (e.g.240v@50a) powers the generator side of the ATS.

> Its automatic....
Its simple - when the Inverter is on, the ATS takes it's power from the inverter. When the inverter is off, the ATS takes power from the grid... e.g. standard grid operation. So all you have to do to work on your solar system is make sure the inverter is off and it reverts to grid power.

The main panel ATS I'm using isProgressive Dynamics PD52DCSV Transfer Switch Surge Protectedhttps://www.amazon.com/gp/product/B0136U0QU4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 -ETL certified.You can go cheaper if you skip the 100a surge protection. The "DCSV" is DC relay coil instead of AC which is quieter. There is a low hum as this is a mechanical relay system and the coil hums a bit - so best its positioned in garage or someplace where a low hum won't bother you. There are some other automatic transfer switches - such as "Generac 100-Amp Outdoor Automatic Transfer Switch w/ 16-Circuit Load Center" - https://www.ebay.com/itm/Generac-10...160458&hash=item56ba52c901:g:Di0AAOSw-A1dRMyvbut I'm not sure they are good at twice daily switch-overs and more expensive. Your electrician may have an opinion.

The main panel manual transfer switch is a way to hook the ATS output back into the main panel circuits and at the same time control which circuits are powered by the inverter. I used the 50a / 10-circuit model https://www.homedepot.com/p/Reliance-Controls-50-Amp-10-Circuit-Manual-Transfer-Switch-A510C/206503336 They make a range of amps and no of circuits. The Generac (above) is 100a and includes a 'load center' - so its kind of a combination of ATS + manual TS.


>Sensative circuits
In the house, the computer/tv circuits will need a UPS as the ATS switches back and forth.

In my case, I went a step further because I had some larger APC UPSs and centralized the UPS capability.You can see these as 4th picture in the 2nd post of the build thread. I used aGo Power! TS-30 30 Amp Automatic Transfer Switch(s)https://www.amazon.com/gp/product/B00153EYTO/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 to power APC 3000va UPS(s). Each of these 3000va UPSs support a 20a circuit - so I can run my K-Cup to keep the clock correct :) As in the main panel setup, the grid provides shore side of ATS and the Inverter the generator side of the ATSs. The ATSs providepower to the APC UPS. The output of the UPS is directed thru a subpanel toregular house wiring to 'upsplugs' thru the house - so I have 1 UPS that powers several sockets instead of having multiple UPSs. But this is just an efficiency measure to combine 8 UPSs into 1 central one. multiple UPSs are fine but each one draws 40watts of idle power - so 8 * 40w = 320w/hour * 24 = 7.7kwh/day of wasted power.

>Expansion is OK
Finally, this ATS method can expand if you decide to grow down the road. I started with 1 at main panel and 2 of them running the UPS subsystem (powered by the 1st inverter), and then this year added a 2nd inverter and a 2nd ATS to power the Heat Pump and 3rd ATS to power some other stuff since I had extra capacity. Just takes some wiring.
 
OffGridInTheCity said:
>Your method is using what I believe is a simple inverter, not all the bells and whistles....
Yes.The Midnite Classic controllers (that I use)have an "AUX1" feature which allows control of external devices. This isused to turn the AIMS on at 52v and off at 49.5v (or whatever you set)thru the remote LCD port - e.g. wires 3 and 5 of simple RJ45 (internet) wire.

If you look at my build thread -https://secondlifestorage.com/showthread.php?tid=8514 The 4th post shows a Progressive Dynamics 240v@50a ATS in combination with a Pro-Tran 10-circuit Manual Transfer switchand discussion to answer @cowpen. The main panel 240v@50a circuit breakers provide the shore power side ofthe ATS and the AIMS 12,000w (e.g.240v@50a) powers the generator side of the ATS.

> Its automatic....
Its simple - when the Inverter is on, the ATS takes it's power from the inverter. When the inverter is off, the ATS takes power from the grid... e.g. standard grid operation. So all you have to do to work on your solar system is make sure the inverter is off and it reverts to grid power.

The main panel ATS I'm using isProgressive Dynamics PD52DCSV Transfer Switch Surge Protectedhttps://www.amazon.com/gp/product/B0136U0QU4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 -ETL certified.You can go cheaper if you skip the 100a surge protection. The "DCSV" is DC relay coil instead of AC which is quieter. There is a low hum as this is a mechanical relay system and the coil hums a bit - so best its positioned in garage or someplace where a low hum won't bother you. There are some other automatic transfer switches - such as "Generac 100-Amp Outdoor Automatic Transfer Switch w/ 16-Circuit Load Center" - https://www.ebay.com/itm/Generac-10...160458&hash=item56ba52c901:g:Di0AAOSw-A1dRMyvbut I'm not sure they are good at twice daily switch-overs and more expensive. Your electrician may have an opinion.

The main panel manual transfer switch is a way to hook the ATS output back into the main panel circuits and at the same time control which circuits are powered by the inverter. I used the 50a / 10-circuit model https://www.homedepot.com/p/Reliance-Controls-50-Amp-10-Circuit-Manual-Transfer-Switch-A510C/206503336 They make a range of amps and no of circuits. The Generac (above) is 100a and includes a 'load center' - so its kind of a combination of ATS + manual TS.


>Sensative circuits
In the house, the computer/tv circuits will need a UPS as the ATS switches back and forth.

In my case, I went a step further because I had some larger APC UPSs and centralized the UPS capability.You can see these as 4th picture in the 2nd post of the build thread. I used aGo Power! TS-30 30 Amp Automatic Transfer Switch(s)https://www.amazon.com/gp/product/B00153EYTO/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 to power APC 3000va UPS(s). Each of these 3000va UPSs support a 20a circuit - so I can run my K-Cup to keep the clock correct :) As in the main panel setup, the grid provides shore side of ATS and the Inverter the generator side of the ATSs. The ATSs providepower to the APC UPS. The output of the UPS is directed thru a subpanel toregular house wiring to 'upsplugs' thru the house - so I have 1 UPS that powers several sockets instead of having multiple UPSs. But this is just an efficiency measure to combine 8 UPSs into 1 central one. multiple UPSs are fine but each one draws 40watts of idle power - so 8 * 40w = 320w/hour * 24 = 7.7kwh/day of wasted power.

>Expansion is OK
Finally, this ATS method can expand if you decide to grow down the road. I started with 1 at main panel and 2 of them running the UPS subsystem (powered by the 1st inverter), and then this year added a 2nd inverter and a 2nd ATS to power the Heat Pump and 3rd ATS to power some other stuff since I had extra capacity. Just takes some wiring.
Click to expand...
Thanks. A lot of great information. I have some simple questions, probably answered somewhere, but unable to find.

I currently have nine (9) 290 watt panels charging my first 14s100p powerwall (about 12kWh or 220 aH), using a single PCM 60X charger rated up to 3kW, pretty much what my 9 panels could produce at maximum. I am adding an identical powerwall. Are these 9 panels enough to charge both powerwalls? If not, I could repurpose 3,6, or 9 other panels (connected to a SolarEdge inverter without batteries) and connect to a second charger if they are needed, but if not really needed, just continue to charge both packs during the day and top off after 11 pm at night with super off-peak grid power. This would be a lot simpler, and would eliminate the need for a second charger, rooftop rewiring, additional electrician fees, and possibly a second inverter.

I am currently looking at replacing my Schneider Conext 4048SW with a Schneider 6848XW pro inverter, vs adding a second Schneider Conext 4048 SW and adding some manual and/or automatic transfer switches. Adding a second Schneider SW would give me more power, and be less expensive.
 
>Are these 9 panels enough to charge both powerwalls?
Its a function of PV input, consumption,and DOD on the battery bank. These are all variable and unique to your case.

In my case, excluding heat/cool (hi variability in consumption), my base homeconsumption is a pretty steady48kwh/day @ 2000w/hr. Thru 2019, with a 6.8kw PV (24 * 285w panels) and ~16kw/day from the battery bank (e.g. average40% DOD) the system produced 24.5kwh/day.


If we takeyour 9panels *280w= 2.5kw PV. That's 2.5kw/6.8kw = 37% of PV power in my example above.
And note that you have2 * 12kwh batteries so you 24kwh at 100% DOD.

This leads me to the following though experiement. (assuming you have similar PV power input weather wise)....
- 9 panels = 24.5kwh * 37% = 9kwh/day with need for at least16kwh * 37% = 6kwh/day from your battery bank - e.g. 25% DOD.
- 18 panels = 24.5kwh * 74% = 18kwh/day with a need for at least 16kwh * 74% = 12kwh/day from your battery bank - e.g. 50% DOD.
Both of these are within range of an OK setup.


Conclusion:
If you have 18kwh/day (or more) consumption then either 9 or 18 panel scenario will work. If you < 18kwh/day consumption that is closer to 9kwh/daythen9 panels would be more effective as you'll just was PV power if you hook all 18 to the battery bank.
 
Thanks to everyone who has replied. Obviously, more than one way to do this. The devil I know may be better than the devil I do not know. So as Daromer stated "just hook it up and double your capacity". Also, I am going to continue to use my 9 panel solar array to charge the system. That is what I have decided to do. My non-solar electrician is still learning, as am I, and we are going to gradually add more loads to our panel to see what this system will do. I am NOT going to try to add any of my 220 volt appliances, 4 AC units, my electric clothes dryer, or electric oven. I am going to try to add just about everything else until we see what causes the battery system to drain too quickly.

For anyone with a Schneider Conext 4048 SW, like I have, this unit just simply will not use the battery in preference to the grid. When set in that mode, it seems just to inject about half the current needed at any given time from the grid, regardless of the SOC of my powerwall. I have seen posts in other groups about this issue, and Schneider has been unhelpful to resolve. In my case, I simply have added a "little gray box" timer, and only allow the AC input to the inverter from the grid from 1 am until 6 am, super off-peak rate of $0.15 per kWh, long enough to totally charge my powerwall. During the day, the PV input is keeping up. If my powerwall starts to run out in the late evening, I can adjust the gray box timer and allow AC input earlier in the evening, but after 7 pm when the peak rate of $0.20 per kWh ends.

If my new 28 pack 48 volt powerwall overwhelms the Schneider unit, I will probably upgrade to the Schneider Conext 6068 XW unit, which works a lot better than the SW unit, according to posts in other newsgroups, and may not have to use my AC timer switch anymore. The XW unit is not quite twice the kW output, but almost, but is twice the price of the SW unit.

Thanks again for all the input. I could not have done any of this without help from this group!
 
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