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Old 24-05-2010, 22:57   #16
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Originally Posted by dennisail View Post
I guess its because the inverters are old square wave? Or just crap? And cant really handle switch mode power supplies
Modified sine wave and sine wave would have nothing to do with it.

Maybe the inverter is bung? Mine has 20A input.

Woul;d an electronics shop have a 12 v power source to check/compare inverters?
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Old 24-05-2010, 23:13   #17
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Modified sine wave and sine wave would have nothing to do with it.

Maybe the inverter is bung? Mine has 20A input.

Woul;d an electronics shop have a 12 v power source to check/compare inverters?
Its the same story on 2 inverters I have tried. Both are ancient units. I could always take a 12v battery in to test inverters. But they are so cheap on ebay. I can get a 3000w pure sine wave for $250, or 300w pure sine for $120.

Will an over-sized unit be much less efficient and low loads? Its always good knowing you can plug a heavy duty power tool in there when needed.
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Old 25-05-2010, 01:12   #18
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Quote:
Originally Posted by dennisail View Post
Its the same story on 2 inverters I have tried. Both are ancient units. I could always take a 12v battery in to test inverters. But they are so cheap on ebay. I can get a 3000w pure sine wave for $250, or 300w pure sine for $120.

Will an over-sized unit be much less efficient and low loads? Its always good knowing you can plug a heavy duty power tool in there when needed.
Have you considered the possibility that the inverters are complaining/shutting down due to volt drop on the 12 volt DC input, in turn due to insufficient cable size.

I bought an Exalto 300 watt inverter with cable connection to cigar lighter socket. With less than 100 watt draw it would raise low volts alarm then shut down until I hard wired it.
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Old 25-05-2010, 01:41   #19
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Yeah mate I considered that. I the problem got better when I started the engine, but was still there. The test I done today was with the inverter clipped directly to a 12V battery.
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Old 25-05-2010, 01:54   #20
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Yeah mate I considered that. I the problem got better when I started the engine, but was still there. The test I done today was with the inverter clipped directly to a 12V battery.
That's exactly what could be expected with insufficient wire size. Volt drop would still be there but because volts at battery would be higher, the inverter would be less likely to complain.

Modern inverters are pretty efficient even with light loads, so would buy the biggest you are likely to need. The larger ones have temperature controlled fans so are generally more efficient anyway.
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Old 25-05-2010, 06:21   #21
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I still dont understand why anyone would run a laptop on an inverter when you can get a DC to DC converter for $20. The losses are too great to go that route...
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Old 25-05-2010, 06:46   #22
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I still dont understand why anyone would run a laptop on an inverter when you can get a DC to DC converter for $20. The losses are too great to go that route...
Thats right. Just waiting for mine to turn up.
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Old 25-05-2010, 09:24   #23
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Pull the battery out and run it off the inverter.

Dimm the screen.

Turn off all apps that you do not need and all hardware that you do not need (lan, cam, etc).

Put it in sleep mode when not in use.

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Old 25-05-2010, 09:43   #24
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BTW our 14 laptop takes up to 5.5A battery in, up to 3.5 A battery out, below 2A battery out, and all toys off. This includes the loss on our 100W inverter, non-sine. It still takes up to 0.5A sleeping. Wondering what it is doing ;-)))

For comparison - our netbook takes half of each and runs all nav soft just as well, if not better.

If you can live with only 9-11 screen a netbook might be the way to go.

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Old 25-05-2010, 10:08   #25
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My educated guess is your power supply.
BEWARE chepo ebay power supples( like the one mentioned earlier) they can and will cause dramaticly shortend battery life. a thoshiba battery runs ,what, about 89? also i have seen damaged mobos and inverter boards because of mismatched pwr.
You can go a little more on the amps BUT not less. get the wrong voltage....
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