I would go for a pure sine wave.
Inverters tend to be more efficient at close to their maximum output , so go for a unit as small as you can get away with. Try to run as much as possible from 12v. On my boat the only thing that the inverter
is used for is the stick mixer for the kitchen. Occasionally I use it for charging
drill or camera
batteries, but I can charge these from 12v, but its a bit more hassle.
Originally Posted by Intentional Drifter
For example, common inverter
loads look like (assuming 12 volt bank converted to 120 volt AC):
Blow dryers (a 1200 watt blow dryer run on the inverter uses 100 amps! Use it for 15 minutes and you have burned over 25 Amp/hours from the battery
Microwave (at 1000 watts, it uses 83 amps through the inverter, or 21 Amp/hours for 15 minutes.)
Ice maker (uses 23 amps through the inverter, so running it for 4 hours on the inverter will consume 100 Amp/hours from the battery
TV (at 100 watts, uses 8.3 amps through the inverter, or 25 Amp/hours to watch for three hours)
PC (at 65 watts, uses 5.4 amps through the inverter, or 17 Amp/hours for that 3 hour movie)
Oink! Oink! Lots of common appliances
are real energy hogs.
The Peukert's Formula will mean that the effective draw from the batteries will be much larger than these figures suggest(although they are mathematically correct). Almost 50% more at 100 amps than these numbers show.
Here is a calculator for the effect.
Notes on Batteries