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Inverter design tho...
 
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Inverter design thoughts

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(@barck005)
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Joined: 54 years ago
Posts: 3
Topic starter  

Pardon, ive only only crashed coursed myself in most of this.   Whats the latest trouble with the receiving of your products from china?  how many boxes is it?   Im sure I can find the answer but where are you guys located, I saw something about the shipment arrived at Long Beach.... so I assume your'e west coast...?  If you're getting the runaround, I have a truck that can get you what's being held up at Long Beach.  I'm In Claremont and Long Beach isn't too far from me.  I like to help where I can although thats a lot of precious cargo to be trusting into someone whose barely made an appearance on here.   I have a question and forgive me its not meant to be insulting but or the guy having the washer machine isssues with the GS inverters, I think he said something about using an extension cord and I assume he uses the same set up for the other inverters that run the washer fine, which to me rules out the extension cord not being the proper size for the amp draw, which makes me wonder if those GS inverters have as close to a pure sine wave as possible because if they rant producing a near closeness to a sine wave then I believe you would be experiencing funkyness with the washer and using those inverters.   Maybe something isn't working right or came lose inside and they arnt producing the sine wave they were designed to produce.  Ive worked with electricity for about 7 years now, one of those years was self taught, another one of those years and half was thru schooling, and three of those years were professionally as an apprentice and then I had family stuff happen and I left the professional world and engulfed myself into the battery world and inverters and the different battery chemistry and how to charge them properly and how to maintain them.  then I got into trying to recover flooded LA batteries and stilll try when I know there aint no coming back from an initial voltage reading of 1.7 volts in a 12 volt battery but still I try.  so when it comes to inverters and batteries I only have my personal experience to offer and the knowledge I read from online sources and from people in forums, and one thing I read was no matter what youll never get a true sine wave from an inverter.  there's just a bunch of things I don't really know too much about inside an inverter that slows the square wave down to have it more closely resemble a sine wave and so I just bout a scope meter to find out for myself.  So another thing about that I came across is that when a machine or motor or like the clothes washer is expecting a pure sine wave and it receives a wave form, from an inverter instead of the nice wave form you see on the graph of the +180 to +0 to -180 and back up again, its like being punched repeatedly over and over again to the machine instead of it gettin punched at those above degree points.  basically it stresses the motor out and is possibly making it draw more power from the GS inverters.  Waveforms that arnt what the device is designed for will also lower its life expectancy.  its just something read and have never been able to test before.  but I think if you invest in an isolated transformer one thet does 120/120 as the primary and secondary then it will clean up the wave form just make sure to protect it w a fuse or similar overcurrent device.  From what I've been reading here tho, I see only quality workmanship going into the products so it could be that extension cord not being the proper awg size and it being too long.   you get a voltage drop every 100feet unless you compensate w a larger wire size.  also,, I have a question and ya I shoulda done the quoted thing about the washer machine not working w the GS inverter, how are your batteries set up? or the bank?  you said just one powered it fine w the other inverters but what's the bank set up when you use the GS inverters?  not trying to insult anyones intelligence but I see a lot of parallel set ups not set up the most effective way.  most people daisy chain them one battery to the next but you're suppose to have each battery connect to one source such as a bus bar or wire nutted to a larger size wire that then goes to the load.  see the pic below for reference.  anyways just trying to help and I don't mind loading up on some boxes if they stuck at port or what not.  not asking for anything so there won't be no bond bullshit or whatever they trying to do these days for imports.  might be a dumb question and I assume its a cost factor but can't you source what you source from Canada or here in the states? or Taiwan or Australia?  or Europe?   is the tariff just on Chinese goods?  Oh I remember now,  about the fans and sourcing them, please try and use brushless and not ball bearing .  I hate fans that die because the barring wear out or rust or whatever.  my friend had some AC powered electrical video display advertisement billboards  you see off the freeway cooling fans.  had four of them. dropped those bastards in a bucket of water while they were running and didnt notice them in there for some time.   those things later almost took my finger off but they were solid.  I think the only company that makes quality products in china is and it won't be spelled right but its something like genzing or Shenzhen products.  you see their name on a lot of dc adapter wall plugs.   http://www.cooltron.com  there's a US dealer and then the one in china.  anything Shenzhen is usually quality from china .  they have good lifepo4 batteries too.   not sure if there's fake Shenzhen companies and that link may or may not be what you're looking for it was just more so for reference of the company.  if you have a way to have the fans be powered on utility and then switch to battery when it senses loss of grid power that be cool. the  less being sucked from the bank the better if utility Is available that is.  youll also want to have one fan in one going out otherwise you willl have negative pressure which a lot of computer type fans don't handle well.  so to alleviate stress and premature death is to have an in and an out.  you can have both going out but have the right amount of inlet holes to lessen negative pressure stress on the fan motor.  fans that do well with negative pressure are inline duct style fans like the ones you see pot growers use.  they attach them to a carbon filter that restricts airflow to the fan making the fan have to work harder to blow air.  but inline duct fans are built for that pressure stress.  computer fan are not.  they burn up or won't push air if the negative pressure is too high for them.  personally I don't care about sound w fans.  it turns into white noise after some time and you don't even notice it and can fall asleep to the constant hum sound or fan moving air sound.  I know heat is a killer for electronics and their performance, I think most people would choose performance over a quiet fan but everyone is different. you can muffle the sound some by adding a duct behind and in front of the fan or make a 90 degree angle for the air to encounter.  it will lower the sound and won't hurt the performance as long as you don't make the path smaller then the fan diameter.   alright well that's about all that came to mind from reading 20 pages of this topic. haha.  

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(@sid-genetry-solar)
Member Admin
Joined: 3 years ago
Posts: 2869
 

Split to a separate topic again....

 

Posted by: @barck005
Pardon, ive only only crashed coursed myself in most of this. Whats the latest trouble with the receiving of your products from china? how many boxes is it? Im sure I can find the answer but where are you guys located, I saw something about the shipment arrived at Long Beach.... so I assume your'e west coast...? If you're getting the runaround, I have a truck that can get you what's being held up at Long Beach. I'm In Claremont and Long Beach isn't too far from me. I like to help where I can although thats a lot of precious cargo to be trusting into someone whose barely made an appearance on here.

The issue isn't transportation, it's paperwork.  Without the requisite paperwork, the goods can't be delivered/moved.  (They're currently in Chicago, IL; Genetry Solar is in Michigan.)  Thanks for the offer though--and yes, trust is earned 😉.

 

Posted by: @barck005
I have a question and forgive me its not meant to be insulting but or the guy having the washer machine isssues with the GS inverters, I think he said something about using an extension cord and I assume he uses the same set up for the other inverters that run the washer fine, which to me rules out the extension cord not being the proper size for the amp draw, which makes me wonder if those GS inverters have as close to a pure sine wave as possible because if they rant producing a near closeness to a sine wave then I believe you would be experiencing funkyness with the washer and using those inverters. Maybe something isn't working right or came lose inside and they arnt producing the sine wave they were designed to produce.

I am honestly not sure what's going on, as I cannot replicate the issue myself--and I've got an HE washer on a GS-based "PJ mutt" inverter.  My best guess at the current time is that the inverter output voltage regulation is a bit too trigger-happy, and the resulting voltage oscillations are causing the washer to trip.  Hoping to see if I can get a firmware update finally (belatedly) sent his way and see if that solves the issue.

We don't have a THD analyzer...but one customer in New Jersey that does, reported that the output of a GS/PJ "mutt" had significantly LOWER THD than the power on the grid.  Not saying that unfiltered SPWM hash can't be the issue, but just that I don't think that's the issue.

 

Posted by: @barck005
and one thing I read was no matter what youll never get a true sine wave from an inverter. there's just a bunch of things I don't really know too much about inside an inverter that slows the square wave down to have it more closely resemble a sine wave and so I just bout a scope meter to find out for myself. So another thing about that I came across is that when a machine or motor or like the clothes washer is expecting a pure sine wave and it receives a wave form, from an inverter instead of the nice wave form you see on the graph of the +180 to +0 to -180 and back up again, its like being punched repeatedly over and over again to the machine instead of it gettin punched at those above degree points. basically it stresses the motor out and is possibly making it draw more power from the GS inverters. Waveforms that arnt what the device is designed for will also lower its life expectancy. its just something read and have never been able to test before.

So you're referring to "square wave" or "modified sine wave" inverters.  (The latter is actually a total misnomer, as it's literally a square wave with a reduced pulse width.)  And yes, I completely agree that these "punch" every single appliance 120 times per second with a slam of power.  Noisy operation, hot operation, premature failure (not to mention a complete failure with light dimmers), and poor device compatibility are expected from these types of inverters.

GS inverters are "pure sine wave" inverters (actually, so are PJ inverters).  These inverters use a high frequency PWM carrier (24KHz in this case), breaking the "sine" up into a number of smaller pieces (24000 / 120 = 200 sine "samples") to much more closely approximate a true sine wave.  This "SPWM carrier" is then filtered out via chokes and the final AC output filter caps (L-C filter), to filter out the SPWM carrier, and primarily leave the 60Hz fundamental.  (Some of the SPWM carrier can be seen as "fuzziness" on the output, but this is very minimal.)

 

Posted by: @barck005
might be a dumb question and I assume its a cost factor but can't you source what you source from Canada or here in the states? or Taiwan or Australia? or Europe? is the tariff just on Chinese goods?

All imported goods are tariffed; Chinese goods have a base tariff of 25% + the item value.  Sourcing goods from the States is practically impossible--for starters, expect a cost TEN TIMES that of a comparable Chinese product (i.e. $5 for China [with tariffs and shipping costs] and $50 for the States [without shipping costs]).  Also getting any sort of customization from a U.S. company is absolutely not going to happen unless you've got millions of dollars and a purchase contract for the next ten years with 50,000pcs, etc.  And last but not least, I can't even purchase "stock" (unmodified) parts from U.S. suppliers: they're backordered literally up to TWO YEARS out.  Ain't got time for that!

The caps for this run are from Taiwan, and we are considering switching from American-made chips to Taiwan-made chips (simply due to a two-year backorder on the U.S. ones).

I'm considering the possibility of sourcing hardwares/transformers, etc. from India or maybe Thailand (as these countries aren't heavily tariffed)--but the huge issue here is that I'm not aware of any good e-commerce platform equivalent to Alibaba for any country other than China.

 

Posted by: @barck005
Oh I remember now, about the fans and sourcing them, please try and use brushless and not ball bearing . I hate fans that die because the barring wear out or rust or whatever. my friend had some AC powered electrical video display advertisement billboards you see off the freeway cooling fans. had four of them. dropped those bastards in a bucket of water while they were running and didnt notice them in there for some time.

terminology, LOL.  All our fans are brushless--and they also are dual sealed ball-bearing.  I would not want to use a sleeve bearing on fans like these; it will fail pretty quickly.

 

Posted by: @barck005
I think the only company that makes quality products in china is and it won't be spelled right but its something like genzing or Shenzhen products. you see their name on a lot of dc adapter wall plugs.

Shenzhen is a huge city in China (population: 17.56 million people in 2020), with thousands of manufacturing companies.  (Some of our suppliers are in Shenzhen--including the manufacturer that has made all of the fans for GS inverters so far.)

Posted by: @barck005
not sure if there's fake Shenzhen companies and that link may or may not be what you're looking for it was just more so for reference of the company.

A whole lot of counterfeit garbage comes out of Shenzhen manufacturing companies too.

 

Posted by: @barck005
if you have a way to have the fans be powered on utility and then switch to battery when it senses loss of grid power that be cool. the less being sucked from the bank the better if utility Is available that is.

All of our fans are DC-powered, so they can't be powered from grid.  (They're also 100% PWM controlled via internal temperatures.)  For that matter, if you're running GS inverters in pass-thru (i.e. AC output connected internally to AC input), the fans won't need to run anyway.


   
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Bossrox
(@bossrox)
Trusted Member
Joined: 3 years ago
Posts: 59
 

Heya Sid, this has been a pet peav with me on A/C chargers in most inverters. I can't see any reason for them & never use that feature. It doesn't make any sense to use grid to charge the batts with the turn around efficiency loss that you'll avoid by just using the grid when you know your taking your batts down more than solar can make up for. I'd guess you throw away a quarter out of every dollar spent on grid to charge batts. So here's an idea.... Maybe building an inverter without a charger option? Less cost to build & sell, just what many might want, right?

Side note on my inverter fan mystery, that update your working on isn't a rush, seems like that temp fix you gave me is holding up fine for now so no rush but when you have something ready to update, just let me know.


   
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(@sid-genetry-solar)
Member Admin
Joined: 3 years ago
Posts: 2869
 

Posted by: @bossrox

Maybe building an inverter without a charger option? Less cost to build & sell, just what many might want, right?

It actually is a rare case of a "free" option--because apart from the AC Input support structure (which a surprising number of customers do utilize), there are no parts added to the LF inverter topology for battery charge.

The same FETs and transformer that are utilized for "inverter" mode...are the exact same FETs and transformer that are used in "reverse" for battery charge.

So yes, battery charge efficiency might be lower than we'd like (~60% - 80% depending on implementation)--but the function also doesn't increase the unit cost by one penny if AC input capability is already present.

If AC input is not desired, the only notable potential cost reductions are the AC switching relays, and two screw terminals on the board (for AC input).  So...a ~$50 cost savings at sale price?

 

Posted by: @bossrox

Side note on my inverter fan mystery, that update your working on isn't a rush, seems like that temp fix you gave me is holding up fine for now so no rush but when you have something ready to update, just let me know.

You beat me to it...I was going to message you to say that this week is being much busier than I anticipated, and I'll have to push the software fix to next week...fingers crossed 😉


   
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