Power chart.

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You just need to be a label reader and have a calculator. Add up the wattages of the devices you are most likely to have powered on all at the same time. That total is the size of inverter but add a bit extra for a safety margin. Nothing complex in the way of math needed, it is your basic simple addition. If you can’t find a label on the device try the product manual.

Of course lots of times folks make sure not to do something like running two 1,500 watt devices at full power at the same time because then you need an inverter that is larger than 3,000 watts.

There are online calculators for converting amps into watts if the label only states amps.
 
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The watts / amps relationship is dependent on volts and is expressed by a very simple equation:

Watts = Volts x Amps

And should be committed to memory for any vehicle dweller. It’s nothing complicated and very important to be aware of.
On the other side of the coin; it was Einstein who said “why commit to memory that which one can look up.”
😎
INTJohn
 
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Check out a simple device for actual checking while using your devices called a Kill-A-Watt meter, cheap and easy for devices you already have if the label is unreadable or you don’t like researching.
 
You just need to be a label reader and have a calculator. Add up the wattages of the devices you are most likely to have powered on all at the same time. That total is the size of inverter but add a bit extra for a safety margin .....
After you have determined the size of inverter you need add a 50% safety factor. There are two reasons for this:
  1. Appliances with motors can use up to 40% more than their rated power on startup.
  2. The current supplied at the rated limit of an inverter can be noisy (i.e. not smooth). This can damage sensitive electronics over time.
 
Thanks everybody. I have always travelled with a bed in the back of my minivan but I am planning on building a dedicated mini van [Transit Connect] and will have a few questions as I go.
 
Thanks everybody. I have always travelled with a bed in the back of my minivan but I am planning on building a dedicated mini van [Transit Connect] and will have a few questions as I go.
Not sure if you've ever watched Nate @explorist.life videos, but he's pretty good with detailed videos. Will Prowse @ diysolar is good, too.
 
After you have determined the size of inverter you need add a 50% safety factor. There are two reasons for this:
  1. Appliances with motors can use up to 40% more than their rated power on startup.
  2. The current supplied at the rated limit of an inverter can be noisy (i.e. not smooth). This can damage sensitive electronics over time.
Something that never seems to get mentioned but IMHO is the MOST important is the low versus high frequency difference in inverters and WHAT they can run..It's not just about counting watts and adding them all together..A low frequency I have that is 1500 watts will run my 8000 BTU wall AC but a 5000 watt high frequency one will not at all... Here is a link to google that explains it all https://www.google.com/search?q=low...i390i650l4.16945j0j7&sourceid=chrome&ie=UTF-8
 
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