Charging my Macbook with power inverter I bought a MotoMaster Eliminator Mobile Power Outlet Digital Power Inverter rated for 400 W.

It has thoses specs:


  AC output voltage: 115 V
  Max Continuous AC power: 320 W
  AC Output frequency: 60 ±1 Hz
  AC Output waveform wave: Modified Sine Wave


I can plug my little iPhone adapter in the inverter AC outlet and it charges.

When I plug my MacBook's adapter, I hear little ticks from the adapter, and nothing happens. I unplug it from the inverter, plug it in the wall outlet, and nothing happens. I have to unplug it from the wall, wait a minute or two, re-plug it to the wall and my MacBook is charging again.

What's happening? I bought this specially to charge my laptop when doing camping. Is there something I can do?
The problem lies in one little word: Modified sine wave. Which typically has a rather tenuous connection with an actual sine wave. Rather, its voltage is a periodic step function with rather few steps (though I can't say for sure about the specific model you mention). You need an inverter that provides the latter. They exist, but tend to be more expensive. I use one made by Mascot, and it charges my macbooks just fine. My previous inverter, with its modified sine wave, did not.