15000W LF, 48volt to 240 volt, what wattage?

[Sid Genetry Solar]

9 minutes ago, dickson said:

Since PJ inverter do not  have the  G to  S  zener diode  this mean  the  25kw  PJ  inverter  will blow up  at  continuous  8kw 

Not necessarily.  Due to the reduced drive strength (assuming the voltage does not spike higher from noise induced in the wires/board), this doesn't seem to be as much of a problem.

But for whatever unknown reason, they run the high-side FETs at 18v...barely 2v under the threshold of the NCEP039N10 FETs.  (Older HY3810s have a 25v max.)

FET failure due to gate overvoltage is usually random and unexpected.  For example, Sean would load-test the early GS control board designs one day (5-6kw for 30 minutes)...and then the inverter would suddenly blow all the FETs just running 150W of lights the next day.

[dickson]

FET failure due to gate overvoltage is usually random and unexpected.  For example, Sean would load-test the early GS control board designs one day (5-6kw for 30 minutes)...and then the inverter would suddenly blow all the FETs just running 150W of lights the next day .   Yes my  15kw  PJ  run  6kw  and  the next day  all the  FETs blow up  when the  switch turn  with no load .    I  change  to rev 11.1  control board and  different  FETs  and  works good  except  for the alarm  with  inductive  load  but the FETs  are good .    The  closup  picture  of the DIP SWI  switch are all set  now to OFF and  no more alarm and run inductive  load  ok .  

[TheButcher]

Regarding blowing up FETs in Growatts and Solarks,  I really can't say much about the solarks but only because I've never come across one here.  There are plenty of Growatts in my area, both grid tie and standalone.  I haven't heard of any Growatts that blew up FETs without good cause, and by good cause I mean more than doing something stupid on the AC output of the inverter.  Lightning is the typical cause.

I did see a USA bsed youtuber grizzling about his Growatt 48V 5kW inverter/charger going bang, but to be honest intuition says it was a fake based on where he bought it.

[dickson]

Regarding blowing up FETs in Growatts and Solarks,  I really can't say much about the solarks but only because I've never come across one here.

The youtube video  show the  FETs  never blow up  because of  over ampage  limit protection like the  GS inverter .  I  have not seen anyone on  youtube  run offgrid  inverter continous  at 12kw  .   The dealer for Growatts and Solarks do not  sell repair parts but do  return on a case by case  basis .   The max  for the 2  inverters is 9kw  not thr 12kw as advertise .  The picture I  found of the  FETs in the Growatts  inverter .   MPP  inverter  do sell  repair parts  and is recommended  .  I will never buy  HF inverter . 

[TheButcher]

So nothing to back up the statement about Growatt and sol-ark recommending people buy spare FETs?

The recent all-in-one HF Growatt inverters are Voltronics.  Their LF units seem to be inhouse and I haven't been able to determine the origins of their transformerless grid tied inverters but I don't really play in that market anyway.  I have repaired damaged Growatt LF inverters, but will not repair grid tied transformerless, too much liability attaches there.

[TheButcher]

45 minutes ago, TheButcher said:

I have repaired damaged Growatt LF inverters

In case anyone was wondering, it was fried serial ports.

Serial ports usually cop a beating when lightning is around.  Even devices that use opto / magentic isolation can be zapped if proper attention to clearances isn't given along with something to clamp transients so they don't exceed what ever the expected breakdown voltage is.  I saw the same in the past when I was repairing PABX cards and ... networked cash registers.

[dickson]

Serial ports usually cop a beating when lightning is around.  Even devices that use opto / magentic isolation can be zapped if proper attention to clearances isn't given along with something to clamp transients so they don't exceed what ever the expected breakdown voltage is.

I  use  surge protector  for the  whole house and  a surge protector for the heat pump .  Do  they  use surge protector in  Australia ?   

[Sid Genetry Solar]

6 hours ago, dickson said:

I  have not seen anyone on  youtube  run offgrid  inverter continous  at 12kw  .   The dealer for Growatts and Solarks do not  sell repair parts but do  return on a case by case  basis .   The max  for the 2  inverters is 9kw  not thr 12kw as advertise .  The picture I  found of the  FETs in the Growatts  inverter .   MPP  inverter  do sell  repair parts  and is recommended  .  I will never buy  HF inverter . 

Took a closer look at the video.  Appears (from what blurry detail I could get) that the main processor is a Texas Instruments TMS320F28035.  Talk about powerful processor compared to what's (quite adequate) in GS inverters...!

• 120MIPs (vs 16MIPs)
• 32-bit (vs 8-bit)

...but does cost 3x as much.

 

Worth noting: Growatt (at least the SPF6000) uses the exact same FET driving methodology as PJ and the rest of the Chinese-designed LF inverters.  If it works for them, great--but I just think it's so funny how little innovation there is in the Chinese inverter market:

• Yellow circle: low-side FET drivers (discrete transistors forming a totem pole driver)
• Green circle: high-side FET drivers (betcha they're the same TLP350 chips)
• Orange circle: multitap transformer-based power supply (2 floating high side taps, and at least 1 more tap for low side and logic)

While the layout is far more concise here, it is worth significant note that I do not see ANY ceramic capacitors anywhere near any of the FET driver quadrants.  Perhaps this is the trick after all, to prevent the FET drivers from providing a fast rise time to the FETs...by not giving them a strong power source in the first place.

I'd be curious to see whether this trick still works in their 12kw inverter...

 

[Sid Genetry Solar]

Found a video of a Growatt 12kw disassembly, and guess what I noticed on the control board:

Yup.  Same driver circuit.

Also worth noting that they only went to 8 FETs/quadrant (same IRFB4110) as opposed to 6 FETs/quadrant in their 6kw.

 

 

[dickson]

Yup.  Same driver circuit  

It is part of the control board so  the design  will  always work  and not blow up the FETs .  Other  review on youtube say it is impossible to run 12kw continuous  because  the current limit will shut down  at 8kw .  This way nobody know  what happen to the FETs  at 12kw and  never get a bad review ?   It is very difficult to run  12kw continuous  that even the 30kw powerjack with the ASL11  transformer  can not run 12kw  continuous .   

[TheButcher]

2 hours ago, Sid Genetry Solar said:

Found a video of a Growatt 12kw disassembly, and guess what I noticed on the control board:

 

Yup.  Same driver circuit.

Also worth noting that they only went to 8 FETs/quadrant (same IRFB4110) as opposed to 6 FETs/quadrant in their 6kw.

Sad but true.  The same thing is seen in the Growatt LF inverters I've had my mitts on.  I really doubt there is a Chinese LF inverter out there that isn't just another clone at heart.  As far as I can tell though Growatt do actually make the ones I've seen.

[TheButcher]

4 hours ago, dickson said:

I  use  surge protector  for the  whole house and  a surge protector for the heat pump .  Do  they  use surge protector in  Australia ?   

Not all that common really.  I live on the coast in QLD Australia in sugar cane country.  There's a fair bit of lightning in storm season  and we've recently had some pretty intense storms statewide including 16cm size hail (yep, that's chunks of ice over 6" hurtling out of the sky...) just north of me.

Usually whole house protectors won't prevent serial ports being fried.  The best approach is to have fast protection on the wires to clamp them and proper opto or magentic isolation with decent clearance on the boards.  The two LF inverters that had fried serial ports were likely caused by induced voltage / current on long unshielded runs of multiwire cable.  The inverters were both on cane farms up the valley and were installed by the same company in the farm's tractor shed with comms run back to the house.  I don't know why they didn't do it wirelessly.

[dochubert]

On 11/13/2021 at 7:58 PM, TheButcher said:

I did see a USA bsed youtuber grizzling about his Growatt 48V 5kW inverter/charger going bang, but to be honest intuition says it was a fake based on where he bought it.

I didn't realize there were fake Growatt inverters.  Assume you are talking about people buying from Alieexpress or similar places?

Also, since you've worked on some and if you don't mind my asking, what do you think the real running wattage limit of a 12kw lf growatt is?

[TheButcher]

Yes, aliexpress etc.  Can't really say what their practical power limit would be as I didn't pay attention to the inverter proper and didn't do any real testing with them as they did actually work, it was only the serial interface that was dead.  The high current DC wiring didn't look out of place for the current though, 48v.

[Sid Genetry Solar]

14 hours ago, dickson said:

Other  review on youtube say it is impossible to run 12kw continuous  because  the current limit will shut down  at 8kw .

Can you provide a link to this review?

[dickson]

Can you provide a link to this review?

The  youtube of DavidPoz say why is it not powering my house well .   Growatt  shut down at  8kw  and Solart  shut down at  9kw .  This save the FETs from blowing up  with current limit protection .   Powerjack rev 11.1 control board  has current  limit  and also  shutdown  so I  change the DIP switch  .   AveRage Joe  later video say he  not try run his Solart  to  12kw because he do not want to know what will happen  but wiil  try in later video .  

[Sid Genetry Solar]

reading through the comments on the video...looks like Sol-Ark isn't all they're cut out to be.

Not only is it only a ~9kw inverter, it can't handle imbalanced loads (GS can, limited by the transformer temperature). 

AND...it's Made in China.  I was under the impression Sol-Ark was a U.S.-manufactured inverter, but it isn't.

 

Hmm...maybe I'd better get back to work on that GS 12kw inverter....

[dickson]

Hmm...maybe I'd better get back to work on that GS 12kw inverter.

The  GS 12kw  will be the first and only  !2kw  to run continuous  in  youtube  if it  work .   A  person on youtube  try with  mosfet that cost 900 dollars each  but quit  after  losing  many thousands of dollars .  It  may need a large transformer core  and  copper wires  .    

[TheButcher]

1 hour ago, Sid Genetry Solar said:

AND...it's Made in China.  I was under the impression Sol-Ark was a U.S.-manufactured inverter, but it isn't.

You aren't the only one.  I thought it was a USA product too.

[Sid Genetry Solar]

7 hours ago, dickson said:

The  GS 12kw  will be the first and only  !2kw  to run continuous  in  youtube  if it  work .   A  person on youtube  try with  mosfet that cost 900 dollars each  but quit  after  losing  many thousands of dollars .  It  may need a large transformer core  and  copper wires  .   

Well, the FET drive has been solved on the GS 12kw...at least right now, the question is whether the transformer core is up to the task of handling a full 12kw.  Got the inverter readout recalibrated, and awaiting another 12kw hour-long load test to see if the transformer temperature stabilizes at a reasonable number.

If not, we'll have to try a (significantly) higher-cost core, see if it can handle the power requirements.  Wire is adequate, FETs more than adequate...just the core at the current time.

[Sid Genetry Solar]

7 hours ago, dickson said:

A  person on youtube  try with  mosfet that cost 900 dollars each  but quit  after  losing  many thousands of dollars . 

You pique my interest, what's the link?

[dickson]

You pique my interest, what's the link?

EVTV Motors  Jack Rickard  paid  someting like  60000 dollars  to have one person try  and gave up and return what money is left .    Jack was doing  one video a week  before he passed  and I  have to look for it .   I will post when I find it  as his video is sometime 2 hours long .  

[TheButcher]

Would be interesting to see the clip, I can't imagine paying someone 60k to fix an inverter and the result is they just tried fitting exceptionally over rated FETs.  Heck, the person that was paid the 60k could hire an engineer to fix it, and still pocket 10k.

[TheButcher]

Sol-Ark-12k-P.  OK.  Someone that doesn't actually read the specs might just go, derp, 'I willz buy it coz it does 12kW as it has 12k in the model number!!' but if they bothered to check the product material it clearly says the inverter is rated at 9kw at 240V, 4.8kW at 120V and while in bypass mode the unit can carry 12kw at 240V and 6kw at 120V through from the grid to the output.

I'm all for good quality products but equally it doesn't hurt to read the manual etc before slapping down 'thousands' on something.

[dickson]

I'm all for good quality products but equally it doesn't hurt to read the manual etc before slapping down 'thousands' on something

Close to 8000 dollars with  tax  and  installation .