Inverters.

yes u r correct thimple, again my 1000 watt does just fine

 

my 1500 watt one has trouble firing up my microwave sometimes

 

i see, mabe its cause my inverter is old like 12 years old , everything was made better the older it is!!

 

No idea what @Brucesmith's reasoning is, but soldering can cause the end of the cable to get rigid and brittle. This can ultimately lead to failure at/near the lug/cable joint. Also, if the wrong flux is used it can allow the ingress of contaminates leading to corrosion.

OTOH, crimping is more likely to leave gaps between strands, also allowing the ingress of contaminates leading to corrosion.

Some would recommend crimp, solder AND waterproof heat shrink. I usually do crimp or solder and heat shrink, depending on the application. For my own inverter installation I did solder and heat shrink on welding cable... never any problems. I also built a set of booster cables the same way 30+ years ago and they're still in great shape.

 

Microwaves take double the power rating to fire up. So a 1500 watt inverter would not be able to start a 1000 watt microwave. You're restricted to a tiny little microwave at maximum 750 watts. Heating anything will take twice to three times that of a normal microwave.