Originally Posted by DreamStreamr
3. you guys have a nice discussion going on running amps and all that. But I haven't seen anyone mention locked rotor amps (lra rating) yet. This is the hard part for the generator if it is sized a little marginally for the loads. It may have the right output to run the appliance, but you gotta start it first and the starting load, or lra, is pretty tough to overcome.
The actual starting amps required are somewhere between the full load (FLA) and locked rotor (LRA) ampere draw, and are weather dependent. Higher ambient temperatures increase the starting amp and running amp requirements.
On the other hand most modern inverter generators can deliver extremely large surge currents compared to conventional designs.
I'm not sure that I buy into the idea that running A/C with a full-load amp draw of 80%-90% of generator capacity will reduce the lifespan of either. A modern inverter generator has excellent voltage regulation so the running voltage should be right in the pocket regardless of load, and the A/C shouldn't be able to tell the difference. As long as the A/C starts OK there shouldn't be a problem.
On the generator side, the question becomes: what limits the useful life of a generator. As long as there is sufficient cooling air and the electronics are kept clean, the life of the gasoline engine should be limiting, and the engine should last more than 1000 hours. The higher RPMs and higher torque associated with an 85% load will shorten the life of the engine, but the $$ per hour are unlikely to double, making it a money losing choice to run two generators with wear and tear on each one.
Besides, experience is that generators are rarely removed from service due to wear and tear from frequent or prolonged use. Loss of confidence due to age, unavailability of service parts, cumulative damage due to exposure to weather, or a changing use case are more common scenarios.