Originally Posted by Rsgtivr6
Gotta figure that a 1000W microwave at 110V would draw about 9A on high. On a battery, that would be pretty rough.
To get 1000 watts an inverter would have to draw (1000 watts divided by 12 volts = ) over 83 amps from your battery. Even in the 4 or 5 minutes it would run to boil water; that would kill your batteries's capacity even if it was FULL to start.
High amp draws to terrible things to deep cycle batteries. They are designed internally to give up their current slowly over a long period of time. Thick plates make it hard to release electrons packed deep in the lead. Much over 20 amps (per battery) and the best deep discharge battery will poop out. I attached a graph showing that reduction on capacity based on current production rate.
If you are going to use a microwave or other high draw item off an inverter, it (the inverter) must be sized to produce not only the running wattage, but the peak starting wattage. I also needs to produce the proper wave form for the Magnatron. Many (including my Magic Chef) require a "Pure Sine" wave form and not the "Modified Sine" produced by cheaper units.
You also need at least 4 12 volt deep cycle batteries to spread the current load over as many batteries as possible so they don't drop below the inverter's drop out voltage in the middle of your popcorn.
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