Power inverter and battery advise?

[star2001]

I'm currently running a generating my AC power to run my two IBM T40 laptops in the field for CCD work. Recently I bought a marine deep cycle battery to run the two laptops. Would it be better to run two separate 100 watt inverters off this one battery or get a 200 watt with two receptacles? I would think it would be better with one 200 watt inverter.

[ronin]

Do not think it would make a great deal of difference, maybe a 200W is less in cost then 2x 100W inverters.

Read about them some time back and what was said was that the inverter will take about 10% of the power to perform the inversion.

So from a 100W inverter each will use 10W itself, whereas a 200W will use 20W itself.

So in that respect no real difference.

From the reading it appeared that if you plug in a 20W item then the inverter still takes 10W or 20W for itself immaterial. It seems to be a fixed overhead. I also assume that they take their 10% immaterial of any other load, in effect they are a constant load/drain themselves.

One inverter means less items around and to carry.

[ChrisLX200]

I understood their efficiency is much worse than that - with a loss nearer 40-50%(there will be losses in the invertor and then the power brick to knock it back down again - both of which get hot in use). Plus, the output is often not a good sine wave and can be harsh on components downstream. Far better to use a voltage converter type device which will output anything up to 24v from a 12v supply. Safer too.

ChrisH

[ronin]

I was just going from what I literally read once about 18 months back, never had a reason to get one for a scope/laptop set up but I was thinking about one for other possible applications.

That would have been a bigger application so maybe at a larger scale they become a bit better.

I would assume that any reasonable make would include the information in the specification.