I ordered the cheap 12k from powerjack and got something else

Hahahahahaha, teeheeeheeheee, marketing 101 🤣😁🤪

At least the past few years, they've only ever used Chinese FETs.  Huayi (i.e. HY3810), NCEPower (i.e. NCEP039N10) and Ruichips (i.e. RUH1H150R).  Never seen an "imported" FET in the inverters.

Now, that's not necessarily a bad thing.   Some Chinese FETs are definitely garbage.  But we haven't had any FET-related problems with NCEPower or Ruichips (as being the only ones we've tried).  My house inverter currently has Huayi HY3810 FETs in it.

FWIW I did try some Huashuo FETs, and those things were a solid definition of garbage.  Flimsy weak, soft leads...and the manufacturer was ashamed to even print their own logo (or a datecode) on the package.

Another point

Motors generally run at a reduced power factor

So 10A resistive load PF1 is 2400W @ 240

but 10A motor load is likely only 1680W due to the PF of 0.7

the FETs will still deal with the 10A load ÷ the duty cycle so a 10A load at .7 has a FET current roughly equal to a 12A resistive load 

 My well pump is a  230V 3 wire pump (2-115V hot, 1 neutral, 1 ground) rated as 1/2 hp. The locked rotor amps (inrush) for 1/2 second is 20.5A @ 230V.

You need to be capable of 25A for a few seconds at the FET level 

The lead-acid battery bank alone has 1050 cold cranking amps at 26V. That would be over 100A at 230V. The LiFePO4 bank supposedly has a 100A BMS.

The battery will never see the FET pulses because of the caps

The way the sign wave is made is through a wave slicer (class D amp)

The instant voltage is generated by what % of the time tha FETs are on

If the peak current is at the max voltage the FETs are on for most of the time but inductive loads the current lags the voltage so as the voltage is decreasing the current continues to rise causing the FET on state to hold larger currents for shorter duration 

Another note my pump only pulls 9A running but my clamp meter shows over 60A inrush

The inrush is much higher than the locked rotor current 

It's possible you could add a cap across the motor increasing it's PF making it more inverter friendly 

I thought inrush meant the same as LRA.

The motor is submerged, 50 ft below ground. I may put a 50uF choke on L1 and L2.

Caps and inductors shift current phase

The motor is an inductor so current lags voltage

capacitor current leads voltage

Putting a capacitor across a motor shifts the current phase back and if correctly matched can get it near 1.0PF actually reducing the run amps

I'm not sure how it would effect inrush 

7 hours ago, Steve said:

Another note my pump only pulls 9A running but my clamp meter shows over 60A inrush

The inrush is much higher than the locked rotor current 

I don't see how the start current could be higher than the LRA nameplate rating.  For a 9A loaded running current, I would expect a much higher LRA than 20A...the 60A you measure sounds about right.  LRA = locked rotor amps = the absolute maximum power the motor can draw.  (The only way to run the current higher than that would be to purposefully drive the motor backwards.)

An itty bitty 1A running current refrigerator compressor will easily have an 8-9A LRA rating.

I found specs from the motor manufacturer. My motor is a 1/2 hp 230V "premium" motor, the second one in the chart.

Looks like your pump is about half the size of mine

I wouldn't expect an issue starting it

There has to be a fatal miscalculation in that specsheet.

The DC resistance of the "Main" winding is listed as between 5.1 and 6.1 ohms (presumably ohms??)

230vAC through a 5.1 ohm resistance = 45A.

I don't know if the start winding is always cap coupled, or switched--but regardless, the start winding is listed at 12.4 ohms resistance.  At 230vAC, that's 18.54A.

So if we add both winding amperages together, you get (45 + 18.5) = 63.5A LRA possible.

...which lines up with the 60A you measure.