i have a modified sine wave freedom 458. that said, my microwave works on it but not at full power. it sounds a little "sick" when running on the inverter. i have heard that is manufacturer dependent. mine is a sharp convection microwave that is common in our coaches. it wont hurt it i believe, but may take a little longer to cook.
my laptop works fine. that said, the power is ok but not "clean" from a modified sine wave. really sensitive equipment may glitch or not work at all on them. i know some power tool rechargers dont like them.
if i had to replace mine it would be with a pure sine wave. but i will not spend the money just cause. these modified sine wave inverters have been in coaches for a long time and still are.
it has not been a problem for me.
tom (changing planes in korea)
here is some info i found on a web site.
Do I need Modified Sine Wave, or Pure Sine Wave? Advantages of Pure Sine Wave inverters over modified sine wave inverters:
a) Output voltage wave form is pure sine wave with very low harmonic distortion and clean power like utility-supplied electricity.
b) Inductive loads like microwave ovens and motors run faster, quieter and cooler.
c) Reduces audible and electrical noise in fans, fluorescent lights, audio amplifiers, TV, Game consoles, Fax, and answering machines.
d) Prevents crashes in computers, weird print out, and glitches and noise in monitors.
e) Reliably powers the following devices that will normally not work with modified sine wave inverters:
- Laser printers, photocopiers, magneto-optical hard drives
- Certain laptop computers (you should check with your manufacturer)
- Some fluorescent lights with electronic ballasts
- Power tools employing "solid state" power or variable speed control
- Some battery chargers for cordless tools
- Some new furnaces and pellet stoves with microprocessor control
- Digital clocks with radios
- Sewing machines with speed/microprocessor control
- X-10 home automation system
- Medical equipment such as oxygen concentrators