powering MBPro with 12V battery
Sometimes use my notebook at remote sites without mains supply. Wondering about options of powering using a 75Ah deep cycle marine battery. I've had a quick search here and note that there aren't any Apple-approved 12V power adapters available, but there are some 3rd party options where it looks like they've modified an Apple power supply for DC.
Another option is to use a 12V DC to 240V invertor. I have one, but it's only about 140W, 300W peak IIRC. I've seen some posts here talking about 85W power supplies. My Apple adapter says 100-240V 1.5A in, 16.5-18.5V 4.6A out. So won't it require 240x1.5=360W? That sounds very high considering the output is only 80W. Is that peak, in which case the one I already have may be sufficient? How do you know what the typical wattage is? What would cause this peak? I'd probably have the battery fully charged, so the invertor would only have to provide the power used by the notebook, not charge the battery as well.
Another option is to use a 12V DC to 240V invertor. I have one, but it's only about 140W, 300W peak IIRC. I've seen some posts here talking about 85W power supplies. My Apple adapter says 100-240V 1.5A in, 16.5-18.5V 4.6A out. So won't it require 240x1.5=360W? That sounds very high considering the output is only 80W. Is that peak, in which case the one I already have may be sufficient? How do you know what the typical wattage is? What would cause this peak? I'd probably have the battery fully charged, so the invertor would only have to provide the power used by the notebook, not charge the battery as well.
Macbook Pro, Mac OS X (10.6.1)
