Stacking Two Schneider Electric SW-4048 Inverters Failure

neutronspin · December 2018

I recently installed two Schneider SW4048 inverters and their stacking kit. Configured one as master and the other as slave. The system ran perfectly except when I decided to power down the system for some maintenance. I started the system per their instructions and I heard a loud clunk from one inverter and it threw an error code that the Master inverter failed. I attempted to restart the inverter and it was dead.

I then contacted Schneider Solar tech support to get a replacement inverter since it was less than two months old and under warranty. Surprisingly I was informed that Schneider pulled their inverter stacking kit off the market and they are now telling me that they can't be stacked. Although they still say stacking is acceptable in their current literature. Am I being hoodwinked by them or what? They said run them separately or nothing and they can't even share a common battery bank even if the outputs were separate.

Is anyone running these inverters in parallel? And is it successful? I would caution anyone who purchases two of these inverters and want to stack them to ask questions. I am now stuck with my purchase and my only option is to go with an XW+6848 inverter or abandon Schneider altogether. I will be stuck with their switchgear and other support equipment if I decide to do this.....any info appreciated. Thank you....

Dave Angelini · December 2018

I will ask Engineering and be back later today, if the fog lifts....

mcgivor · December 2018

Let's suppose you bought a four wheel drive truck which the manufacturer claimed would get you out of the mud, snow or whatever, but later claimed the four wheel drive in fact didn't work and you would need to buy a second truck, that would have to be driven by a second driver to achieve four wheel drive, only it wouldn't work as advertised. A recall would be issued to address the shortcomings, and the truck would be either replaced or repaired to meet the claimed performance, not an up sale to a higher model. As a consumer there are specific rights which protect one aginst fraudulent advertising, but in reality I think tech support is only a frontline, the matter will be better dealt with those higher on the food chain. Don't give in prematurely, Schneider will support you, eventually. Usually the vendor is the go between with regards to warranty claims, they at very least, should peruse the matter.

Horsefly · December 2018

Maybe I'm misunderstanding, but if Schneider says they have pulled the stacking kits, why is it still available from the host of this board?

https://www.solar-electric.com/schneider-electric-sw-conext-ac-stacking-kit.html

Estragon · December 2018

Just to clarify, did you install both the stacking kit and the interlock/breaker box (sold separately)?

Without the interlock, it would be possible to put bypassed AC onto the inverter AC output, in which case the resulting release of magic smoke likely would void warranty

Just a thought.

neutronspin · December 2018

Estragon said:

Just to clarify, did you install both the stacking kit and the interlock/breaker box (sold separately)?

Without the interlock, it would be possible to put bypassed AC onto the inverter AC output, in which case the resulting release of magic smoke likely would void warranty

Just a thought.

No....I installed their stacking kit per their installation manual. The kit provides a new interlock plate and breakers to use in the parallel mode. They worked in the stacking mode for a day fine but when I turned the system down for maintenance and restarted both inverters per their instruction sequence I got a code that stated the Master Inverter Lost. From what I understand both inverters must communicate with each other in order to put them in parallel. If they loose communication bad things can happen. I assume this is done over the XANBUS. The old original Xantrex design used a stacking cable to accomplish parallel operation which connected between the two inverters. It is like bringing a gen set online and synchronizing it to the grid. If they are out of sync bad stuff can happen. I don't know what happened just the code# 75 Master Inverter Lost. After that the Inverter was dead. I lost all confidence in the inverters to do as they were designed.

neutronspin · December 2018

Horsefly said:

Maybe I'm misunderstanding, but if Schneider says they have pulled the stacking kits, why is it still available from the host of this board?

https://www.solar-electric.com/schneider-electric-sw-conext-ac-stacking-kit.html

This is what their support said that they will not continue the stacking kit. Don't know if they pulled them off their vendor network stock or even if this is true. This is what I was told....Also I was told that stacking won't work although they have it in their current Installation manual....

neutronspin · December 2018

mcgivor said:

Let's suppose you bought a four wheel drive truck which the manufacturer claimed would get you out of the mud, snow or whatever, but later claimed the four wheel drive in fact didn't work and you would need to buy a second truck, that would have to be driven by a second driver to achieve four wheel drive, only it wouldn't work as advertised. A recall would be issued to address the shortcomings, and the truck would be either replaced or repaired to meet the claimed performance, not an up sale to a higher model. As a consumer there are specific rights which protect one aginst fraudulent advertising, but in reality I think tech support is only a frontline, the matter will be better dealt with those higher on the food chain. Don't give in prematurely, Schneider will support you, eventually. Usually the vendor is the go between with regards to warranty claims, they at very least, should peruse the matter.

I hope you are correct. I have spent a considerable amount of time and expense in setting up my off-grid system. A recent brand new 7.2Kw rooftop professionally installed array and four of their inverters and other Schneider Electric support equipment over time.....

Dave Angelini · December 2018

This is what I was told.

"Really appreciate you bringing this is to our attention. It certainly does seem we've got some information gaps to fill on CSW. Yes we did have some firmware issues that lead to some hardware reliability problems on CSW and we did communicate that we were not supporting stacking while we were working on fixing it. However it is all fixed now and I don't think we've done a very good job getting the messaging out there that it's ok now."

So, If I were you I would go back to my vendor and get them to do something with support. From what i can tell the firmware needs to be latest and often people add the second Inverter later and may not have updated the firmware.

neutronspin · December 2018

Dave Angelini said:

I will ask Engineering and be back later today, if the fog lifts....

Thank you....I have a

Dave Angelini said:

This is what I was told.

"Really appreciate you bringing this is to our attention. It certainly does seem we've got some information gaps to fill on CSW. Yes we did have some firmware issues that lead to some hardware reliability problems on CSW and we did communicate that we were not supporting stacking while we were working on fixing it. However it is all fixed now and I don't think we've done a very good job getting the messaging out there that it's ok now."

So, If I were you I would go back to my vendor and get them to do something with support. From what i can tell the firmware needs to be latest and often people add the second Inverter later and may not have updated the firmware.

Thank you for the reply. I have opened a case with Schneider Support and hopefully they will send me a replacement inverter. I must have misunderstood what was said from the support staff person but I was in the dark until you explained the issues and resolution. They said they will replace the inverter and hopefully I can get my system up and running again.

I do have a question as to the firmware updates. Does this include the ComBox and my MPP60-150 controllers and the rest of the support equipment? I assume the latest firmware is on their website for download. I replaced my two original SW4024 inverters with these 48 volt units as I upgraded my battery bank to 48Vdc. As I stated in other posts these inverters performed flawlessly until the Master failed.

Dave Angelini · December 2018

You are welcome. You must always have a number with Schneider, Always. They are huge and will lose you in the noise without a case number.

If you are full time offgrid in my opinion, you should be using the xw+ series. They are built for longer life and the warranty reflects that. They are also field tested more, mature, and are the one to use for critical power.

You should hear the stories I am hearing lately about Outback so keep calm.

The mppt-60 is mature and there really is not much firmware that would cause your issue. The CSW does not need a combox so that is not the source here. I think that you had 2 different firmware builds in your 2 CSW's. It worked until it did not. They will walk you thru it or replace the CSW. All the firmware is on their website and it has release notes with what they fixed, or attempted to

Good Luck

neutronspin · December 2018

Dave Angelini said:

You are welcome. You must always have a number with Schneider, Always. They are huge and will lose you in the noise without a case number.

If you are full time offgrid in my opinion, you should be using the xw+ series. They are built for longer life and the warranty reflects that. They are also field tested more, mature, and are the one to use for critical power.

You should hear the stories I am hearing lately about Outback so keep calm.

The mppt-60 is mature and there really is not much firmware that would cause your issue. The CSW does not need a combox so that is not the source here. I think that you had 2 different firmware builds in your 2 CSW's. It worked until it did not. They will walk you thru it or replace the CSW. All the firmware is on their website and it has release notes with what they fixed, or attempted to

Good Luck

Hello,

Schneider Electric replaced the inverter and we are back up and running great....hats off to Schneider....thanks again....

jtdiesel65 · January 2019

I've used the sw4024's and eventually (after like 5 replacement inverters) schneider sent me two xw and never had a problem since. IMO the sw's are buggy when stacked. Here's my thread on my issues https://forum.solar-electric.com/discussion/20058/fried-conext-sw4024#latest

neutronspin · January 2019

jtdiesel65 said:

I've used the sw4024's and eventually (after like 5 replacement inverters) schneider sent me two xw and never had a problem since. IMO the sw's are buggy when stacked. Here's my thread on my issues https://forum.solar-electric.com/discussion/20058/fried-conext-sw4024#latest

Hello....thank you for the reference thread. The similar thing happened to me as well. The instructions for the stacking kit had the output neutrals tied to the input neutrals I believe. I also had some firmware issues as well. Now both inverters have been running good for now but I have not tried to run the input with my genset. I am using AC grid support now. Am scared that it may destroy another inverter. I am going to research further into this. Also I am contemplating adding a relay on the AC inputs to remove the AC at a specified SOC from my MPPT controllers since the "consumption" mode doesn't work very well...I noticed today since there hasn't been much solar input my battery bank is at 67% SOC and the charger has not come on in either inverter. They both have chargers enabled and the recharge voltage is set on both to 50 VDC. Battery voltage is at 47.3 VDC and neither charger is on. I am sorry I have these inverters now and would jump at the chance to replace them with the XW+ but it won't happen.

grmln01 · April 2019

I recently installed two Schneider SW4048 inverters and their stacking kit. Configured one as master and the other as slave. The system ran perfectly except when I decided to power down the system for some maintenance. I started the system per their instructions and I heard a loud clunk from one inverter and it threw an error code that the Master inverter failed. I attempted to restart the inverter and it was dead.

has there been any resolution to this issue...….I tried to start two stacked sw4048 inverters last night and got fault codes referencing ac outputs are out of phase thought that I should up date all firmware but now after reading this thread I may need to quite before I burn something up...…….

MrM1 · April 2019

I think the firmware of the SWs has to be latest or it is likely not to work well.

I've looked at the list of improvements in the latest firmware, but have been reluctant to update Bc it does not look like anything that will benefit a single SW in my configuration.

Stacking Two Schneider Electric SW-4048 Inverters Failure

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