THE CHEAP POWER INVERTER OPTION
A way of providing real non-
generator power in the bush is to use
an inverter. For a long time these have simply been to expensive
except for low power requirements but recently Chinese imports have
changed this like so many things. This option is now worth a
serious look, and can be the cheapset Watt/dollar option available.
I have a need to use a jack hammer and angle grinders in the bush and
while my generators can do the job its a time/space/weight waster to
set one up. With the inverter its plug in and switch on!
And amazingly the inverter delivers the goods for a weight of only 5kg,
about a third that of those cute Yamaha/Honda 1kva items, whilst
actually out powering them at the same time and to boot being a lot
quieter (with non-diesel engine car running), and leaving a $1000
change in your pocket.
Its disadvantage is that for any serious power output you should run the
car engine and as best as I can tell it uses around 3 times the fuel.
In reality though the actual cost of cooking tea or whatever is still
very low however the inverter option is in my opinion more suited to short
1/2 hour type applications than long running times which favour a generator.
(Note- Our trip setup is car only - no campers and big battery banks)
Not withstanding this, if your just charging your laptop or some other
light load, then the inverter is fine for hours without an engine
running.
I brought my 1500W inverter from EBAY for $200 + $20 delivery from
Waterside trading company, who seem to sell lots of them from $200-$300
and still do as of this date 27/11/06.
From many stores
inverters in this power range cost nearly $1000 but
a similar model to
mine is available from Jaycar under the "Powertech"
brand label for $600 retail (cat MI5114). So for nearly 3 times the
price you get a certified to Australian standards unit and no doubt
better warranty and service options, and Australian only 240v plugs.
I couldn't even find a single reference to "who made mine" in the
advertising or skimpy manual that came with it.
Take your choice!
The actual inverter is a very impressive unit and lives up to its
claims
well. Its is very efficient and takes a long time to heat up
and switch on its twin cooling fans. It has multiple over/under voltage
protection modes and can even display the car battery volts and the
power output in watts it is providing.
The standby current without a load is 1.4amp -> which drops to only
0.5 amps in few seconds as the fans turn off. Amazing for a device
that can supply 2 horsepower of mains power.
My unit easily provided 1400w at 11.9V. This was all my battery
and car generator could provide whilst delivering 135 amps.
With its 90% efficiency only 140w would be lost and heating up
the inverter. I couldn't measure this accurately but was able to
cook 4 slices of toast without the inverter getting hot or its
cooling fans operating so it clearly is an effect device.
These
inverters are not sine wave devices and generate a square wave
designed to approximate the power that mains appliances use.
Even with good equipment I found it hard to measure this
approximation accurately and estimate that the inverter delivers
about 90% of the power to an appliance that it would use from the mains.
This is partly because they run at about 230v whereas the mains is often
240 or more volts. As they are also only 90% efficient this cancels out
when working out loads and as a rule of thumb if the appliance draws
500w it will draw about the same from your car battery.
E.G. With a lux meter I measured light output from 3 different light
sources and it was 10% higher running from mains at 240v than the inverter.
The inverter runs most things from lights to small fridges, angle grinders
drills, immersion heaters, small oven,small kettle, toaster and things of this
nature however you should not assume it will run everything and if
something is particularly important I would check first.
A real test for
mine was my 1500w electric circular saw.
This gave the inverter something to think about, as the start up
current on some electric motors and compressor driven items can be
3-5 times the running power.
Mine is rated at 3000w surge, and as I switched on the Saw the red
over-current light came on. However these new
inverters have a sort
of soft start mode in which they cut in/out a few times to get motors
running and after about 3 seconds of will I /won't I the Saw spun
up to speed and I made short work of some branches blocking my way.
The inverter also gets around the problem of cooking on total fire
ban days with gas appliances, and these days authorities tend to
be not so happy with generators and many require knapsacks at the
ready and large clear spaces.
Other advantages include the ability to deliver power at a
distance via lightweight 7.5amp extension leads in a way that
we could never do with our 12v equipment.
We configure our setups dependant on the trip, usually
camping out the back of the car and surprisingly the inverter
can actually mean less net load complication and my wife is
a lot more comfortable with it than a generator.
While the Inverter can sit comfortably under our Nissan
Patrol's front
seat, we prefer to set it up as required
with bonnet up on a special little mounting plate as opposed
to a permanent fixture. To make this setup practical we have
a permanent 175amp Anderson plug lead across the battery which
allows for a quick connect/disconnect set up.
Note- 175amp Anderson type plugs vary massively in price. Jarcar
list them at $37.95, typically their about $25 each whilst we paid
$16.35 from Australian Warning systems in Vic.
A couple of unusual uses have been found for our setup.
There is often bikes and bruises around our
camp and a 300w infra
heat globe is worth its weight in cheap wine.
We usually carry a cheap 18AH SLA battery for powering lights
, radios etc when the car is away from
camp and the inverter will run
light loads quite happily from it such as my 60watt soldering iron
and for the ladies a compact and cheap fan.
Which 240v items are on essential depends on your point of view.
While a small electric chainsaw for Xmas looks good to me I am
currently in a skirmish over Hot-rollers , but am still holding
the line on the wifes hairdryer.
I would not reccomend to have all your important stuff running
via a generator/Inverter or any other single power source for
that matter when bush as a single failure can effect everything
dependant on it.
We carry both gas and 12v devices for lighting/cooking
etc even when taking 240v equivalents.
Conclusion
------------
Its the ability to provide serious power, cheaply, easily
in a small package without weighing down the car and to
allow one to use a myriad of already owned devices that
has made the inverter a practical
camping accessory for us.
Robin Miller