Hi all i started my tramping job about a month ago and now i wish to get a inverter to power a tv and maybe a microwave. What size watt would be best to get for the job
As this has been done quite a few tomes before, I’ll bullet point for speed.
Power: Twice whatever the device uses so if its a TV using 100W, you need at least 200W inverter. Make sure its continuous power NOT peak rating as peak is for first 1/2 second only.
Type: For many devices esp laptops you need pure sine wave rather than modified sine wave.
Connector: For anything more than 100W it’ll prob need to be wired to the battery, or anderson lead professionally, unless you an auto electrician. Cig lighters don’t cut it.
Price: Buy quality not cheap chinese to ensure it actually works and doesn’t burn the truck out. Boss wont be happy if you do. 
Microwaves: Check actual power usage on back, not what it says on front. Eg, 700W microwave prob uses 1500W. They also prefer pure sinewave.
Deep fat fryer: Don’t even think about it. 
I have a 2000w modified sine wave inverter made by Ring. I run a 700w microwave, 900w travel kettle and a 19" led tv, not all at the same time though. I also run the engine whilst the kettle or the microwave are in use. TV and laptop run with no problems at all even though its a modified sine wave inverter.
The inverter is hard wired into the batteries with an inline fuse fitted.
Hope this helps.