Date: Fri, 30 Jan 2009 07:51:19 -0800
Reply-To: Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Subject: Re: 12V power inverter ?
In-Reply-To: <eccfedcc0901300648m521ca9f7ofa97b30ebffb4597@mail.gmail.com>
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I have used a wide variety of Xantrex inverters.
Only the ones that say "True sine" on them supply an actual sine
wave similar to what is in the outlet.
Others supply an approximation by quickly (I measured my 1000W to 70kHz)
switch a square wave, so that the average approximates a 60Hz sine wave.
This they often call a "modified sine wave". It will work with most
equipment, but can damage some. Often the equipment will run slightly
warmer due to the high frequency harmonics of the switching.
The only equipment I have actually broken using one of these inverters,
was a NiMH battery charger. I have more often broken the inverters
by plugging in a too big load. (They are supposed to be current protected
but that apparently does not always work. I have from 150W cig
lighter plug inverters for use in the car up to a 1500W unit for the
'82 Westy)
--- On Fri, 1/30/09, Michael Sullivan <sandwichhead@GMAIL.COM> wrote:
> From: Michael Sullivan <sandwichhead@GMAIL.COM>
BTW_Also have this printer to use wirelessly. Brother
> MFC-845CW
> Average 6.5 W
>
> Average 9 W
>
> Average 34W
>
This ought to work with your 75W inverter.
> Off HP LaserJet 1020 250 W 2 W 0 W
At 250W this one most definitely won't.
> >> I'd worry more about the printer. Most cheap
> inverters have either square
> >> wave, or "modified sine wave" (which is
> nothing like a sine wave) output.
> >> Electronics aren't always happy with that. I
> can charge my laptop using one,
There is definitely a risk of damage, but it is not huge.
To elaborate a bit more: Anything with a wall-wart or laptop
type supply is running off a low DC voltage. Using it with
the inverter risks overheating the wallwart transformer, but
only to a limited degree risks the actual equipment.
By contrast, a laser printer runs directly off the household
current. Hence an inverter square wave will enter the equipment itself
and could damage it. Furthermore the laser printer as you noticed
in the spec uses much more power. (My brother 2030 actually peaks at
900W as measured by a "save a watt" plug meter)
One step in the printing process involves fusing the
toner permanently onto the paper. To do this a high wattage
heating element is switched on (and off).
A reasonable rule of thumb is to buy an inverter twice the wattage
of the sum of equipments you want to run simultaneously.
For Canadians: Most Eliminator inverters are just rebranded Xantex
They come up on sale regularly in Canadian Tire. Their web page updates
the sale prices every Fri. This week the Xpower 300W Inverter
Product #11-1870-6 is on 1/2 price for $25.
In the US you can buy from Xantrex outlet (web shop) or local
sales.
Martin
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