Inverter reliability

The only thing I haven't been able to get rid of it the little nipple on the bottom of the waves. 

2 hours ago, AquaticsLive said:

The only thing I haven't been able to get rid of it the little nipple on the bottom of the waves. 

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Is that at no load, or under load?  The real test is when an inverter is under load 😉.

It's at about 670 Watts at the time in that picture so yeah not a heavy load.  Once I gets over 1000 Watts its gets worse the peaks flatten out but a still have a little bump on the bottom wave.  The flattened waves is just the world of PJ from what I have seen so I haven't worried about them getting flat on a heavier load.  The load I am running is a portable AC exhausting out the passenger window on my ambulance so about 670 Watts is the normal.  I haven't been running my rooftop AC for the last two weeks haven't needed to run it has been a bit nicer so the portable one can handle it.   

I'd like to see the resumes and other documented technical achievments of Sid and others posting on this forum. How about a resume forum.

I'd like to see the resumes and other documented technical achievments  .........     

Since I posted   eariler  I  have to say  making and selling  off-grid  inverter  need no resume  as anyone  can do it with parts from China .    IF the inverter is connected to be grid-tie  then a lawyer degree  and a engineering  degree will be helpful in case  of lawsuit  or  user  miss connection  L1  N  L2   and ground  .    I  have a electronic  degree and construction  contractor licence  but I  never want to  fight  with the utility  that have all the power in the USA .   My relative are also lawyers .   I am retired .     BYE .   

3 hours ago, Czar said:

I'd like to see the resumes and other documented technical achievments of Sid and others posting on this forum. How about a resume forum.

Well, I'm a country hillbilly without a single degree, papers or any sort of recognized classes, courses or credits.  Except for the school of hard knocks, and hands-on experimentation (without following courses or having instructors).

OK, well, I take that back...the only school I've ever taken was for HVAC service/repair, and I admittedly haven't done much with that.  Not my idea of fun.

EDIT: HVAC school was fun when it came to the electrical portion...I thought it a bit comical that one of the last days, one of the instructors had left--and taken some notebooks with him.  That meant that the remaining instructor had no idea which button on the "test rigs" did what--so we basically hit each button in turn and wrote them out a manual for what button broke what 😉.  Right up our alley...

yeah, your inverter probably has a 36v / 230v PJ tranny spec, which simply doesn't have enough range with normal battery operation!  If you want 240vAC out, that means (230v / 36v = ratio of 6.38, so 240v / 6.38 = 37.565vAC input required * 1.414 [square root of 2] = 53.117v battery voltage absolute minimum for a pure sine.

And of course, under load, due to the losses in the transformer, that required transformer input voltage goes significantly higher.  Not impossible to unwind a turn or 2 off the primary side (as it's on the outside), but I guess the real thing is...if it ain't broke, don't fix it 😉.

yeah, your inverter probably has a 36v / 230v PJ tranny spec, which simply doesn't have enough range with normal battery operation!  If you want 240vAC out, that means (230v / 36v = ratio of 6.38, so 240v / 6.38 = 37.565vAC input required * 1.414 [square root of 2] = 53.117v battery voltage absolute minimum for a pure sine.

Exactly  why my battery input is 62 vDC  with 16s lithium-ion  and not 16s  LIFEPO4 .  

Just one tiny little example of my accomplishments is developing the worlds tiniest op amp, the onsemi NCS20282: https://www.onsemi.com/products/signal-conditioning-control/amplifiers-comparators/operational-amplifiers-op-amps/ncs20282 . Actually the NCS20282 is the tiniest dual op amp since TI has the tiniest single, the onsemi NCS20182 puts two op amps in 1 mil square while TI puts one op amp in a 0.64 mil square. NCS20282 did over 6 million bucks its first year. The rest of what I've done is the size of a book. 

I'm mostly self taught

Raised by an election

Repaired TV vcr amps for years (a few in a shop)

Repaired aircraft electric equipment for about a decade including sign and square wave inverters 400Hz sign 1Khz square

Lots of generator control units (glorified regulators)

Ect

Just one tiny little example of my accomplishments is developing the worlds tiniest op amp,

My friend work  for Motorola when  On Semi  was part of Motorola  a long time ago  .    Now  On Semi  is a large  company  and no   more Motorola   in Arizona   but On Semi  is still here  .       Your chip is tiny .     

I'd rather adjust the tranny than run an obscure voltage...

'd rather adjust the tranny than run an obscure voltage..

I  think I am the  only one in this forum  running  62 vdc  with lithium-ion battery .      Very dangerous  as over  charging  68 v  the battery  will explode  and  I  make sure the  battery  voltage to the PJ inverter is less than 65 vDC or the  FETs will blow up .     

Yes, i think you are.

Curious to know your rational to run such a unique setup... Eg, why not run a safer LiFePO4 and unwind the tranny a couple turns to compensate for the voltage difference?
Oh, as an aside, do you do solar? How does that odd voltage work with typical mppt equipment?

Very different from my MO. I like commodity, inexpensive equipment that you can buy nearly anywhere, even at the expense of functionality if necessary. 12v Batts, get-them-anywhere 24v alternators (48v alternators are still exotic), most mppt controllers work, and simple wifi smart-shunts for tracking power.

Oh, as an aside, do you do solar? How does that odd voltage work with typical mppt equipment?

I started  just 3  years ago  with a very small  setup like yours  just a  backup  to run the  freezer  when the grid go  down .    I expanded  with  2 sunpower  solar panels  60 voc .   I  got  a  15kw powerjack inverter  running with  4 AGM battery  and  60voc  solar panel to charge the battery  directly  with  2  EPever  24v  MPPT  in series .    LiFEPO4   was  new  and  more expensive 3 years ago   than  used BMW  16s lithium-ion .     I charged to 66 volts  with e-bike charger  and  equalize  with the  AGM for a minutes down to 62  v  and run the  48v  15kw PJ .     The  cheap MSB solar controller  is  the MPPT that can charge to 66 v .     Typical  MPPT do not  charge to 66 v .    Now I  will not  use  lithium-ion  battery  but  remove  2  turns from the  transformer  primary  and check the output with a variac .      LiFEPO4  is what  almost  everyone use  .     My  8kw PJ  run with a 200 amps  alternator I made for my car  and use it a  couple times  to test at 14 volts .    MY  off-grid  system  expanded  now to a  point of no  return  and will paid for itself  in 6 years  if I  can run a  4 ton heat pump  during the summer  off-grid .   In California  you  can  go off-grid  and  have free energy  with lots of  sunlight  and NOT need a 4 ton heat pump .