On Mon, 14 Mar 2005 20:18:08 GMT, "Harry Bloomfield"
wrote:

legin wrote :
Hoping to start my self build shortly and the thought of power has
crossed my mind. Have been looking at genertors and obviously these
would do the job but they use 2-3 gallons a day if run constantly,
Average say £10 per day = £50 per week, would soon add up. I know it
could be started and stopped with each mix but this is more work and
hassle. A thought came to mind. I have several van batteries about that
still hold a decent charge. A 600w invetrter can be had for approx
£60- £70. me thinks ah that'l do nicely. However one of the
inverter's destructions says it won't work drills, saws in fact
anythink with a motor as it is a modified sine wave. Has any one tried
it ? Any other ideas from the group. Yes, I could possible tap a
neighbour up but don't want to burn my bridges just yet.

I doubt it would work at all and even if it did the batteries would not
last very long. The output is a rounded square wave, not very
acceptable to motors. Also think of all the recharging and heaving of
those batteries about.

It will *eat* your batteries. Think about it. 600w at 12V = 50A. A
typical vehicle battery is a lot less than 100 Amp hours, and for these
purposes is useless at 50% discharge. So you'll get less than an hours
use per battery, taking it from full to dead. And they don't like
this sort of use, not one little bit. That's what you pay for in
"leisure" batteries.

Also a 600W inverter, while it might turn a 600W tool, will never start
it.

I've used hand power tools off an inverter, driven from a running
engine, without problems in terms of waveform. But you can hear the
engine note change when the tool bites.
--
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