4kw-12kw pure sine wave inverter does not power up deep well pump

The original intention was to have the Honda 7000 as a backup to the system including auto start. (see previous post re inverter not recognizing generator power) My 4kw-12kw split phase pure sine wave inverter does not power up deep well pump But when I researched the spec of the inverter it showed that it supported a 240v 1 hp pump. I now recognize that we should have installed a soft start pump but I would like to know if there are any other more cost effective alternatives.
Comments
here's the generic starting specs, I use a 6kw 48V inverter & 800ah battery to power a 1/2 hp pump. It's a quality inverter and has had no issues for 10 years. Power Factor can eat up some of your inverter capacity, different brands of inverters deal better with poor PF.
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