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Second powerwall, what do I need?
#1
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.
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#2
hahah, you already created a 2nd one Tongue

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.
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#3
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.  


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 price but 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 or 12,000watts 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.       
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#4
(03-05-2020, 02:30 PM)Korishan Wrote: hahah, you already created a 2nd one  Tongue

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/inverter...NCONSW4048.  

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.
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#5
You need a shrink Wink

Nah just hook it Up in parallel and double your battery capacity
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#6
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.
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#7
@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.
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
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#8
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.
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#9
(03-05-2020, 02:14 PM)drspeakman Wrote: 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.


I install SolarEdge inverters in 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-s...-inverter/
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#10
(03-05-2020, 04:06 PM)OffGridInTheCity Wrote: 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.  


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 price but 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 or 12,000watts 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.       
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?
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