INVERTERS???

Dont believe ALL laptops run on straight 12 V because they dont.

One of mine is 10.5 V one is 19V and both require converter packs to both run and charge off either 12 or 240 v Most tablets and phone chargers are 5volt, the same as USB power.
My Sony camera battery charger is also 5V and my Sony video camera charger is 8.4V output.

the amount of power used in charging your items will be same with either item but in addition to that power use, the 600w inverter will use more than a 150w inverter to simply run the inverter itself with nothing connected but in the scheme of things it will be a pretty small amount.

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Hi LL,

Inverters have inherent losses of generally two types. The first loss is a "standing loss" which occurs even without a load on the inverter. It is not large, probably less than 5% of the inverter's capacity and does not increase with the load. The second loss is related to the load placed on the inverter and is typically about 10% to 20% of the load depending on the inverter type and quality. So the total loss is the sum of these.

Accordingly, you would waste less energy if the inverter was no larger than necessary for your maximum load. But it may be prudent to select a bit larger to allow for future possibilities.

All that I connect to my inverter are computer and camera chargers. It is "pure sine wave" and 230v, 360 watt capacity. I never come close to full loading and the small 'standing' loss is insignificant.

I prefer to use the 23vac chargers that are supplied with the devices rather than purchase a whole second set of 12vdc powered chargers of perhaps doubtful performance and quality.

So, to answer your specific question, yes your 600W inverter would waste more energy than a 150W inverter supplying the same load. However, if using it whilst driving with the vehicles alternator supplying the power, the losses are of little consequence and it would hardly be worth the cost of replacing the inverter. Even if you are using the inverter with a stationary vehicle it is not a big deal.

There are some who decry the use of an inverter with a travelling vehicle for fear of a 230v electric shock but I do not consider that there is a significant risk if it is all correctly installed.

Just on laptops - mine runs on 19V. To charge it I can use either.....the supplied 240V charger, via a 600W pure sine wave inverter* that I have for various appliances....or......a Powertech a multi output 12V unit (6 different selectable output voltages, 15V to 24V) ...as is usually the case while touring, plenty of electro-options can be very handy at times....just a question of how much stuff one can actually take !
*I'm no electro-tech so I just got the smallest output inverter that I thought I could get away with - as mentioned by the experts above, a moderately larger inverter 'taking it easy' probably only uses a littler more energy than a smaller one working hard (sounds like electro-logic to me :-)......

Laptops and Tablets are best charged using 12v cigarette adapters etc, no need to create 240Vac unless it is something specifally 240v

We have finally eliminated all 240 Vac requirements from the car. I installed multiple USB sockets for charging the "toys" and purchased a 12V DC cable for the laptop.

Fixed. No need for an inverter now. No 240V.

I installed two x dual USB sockets similar to below into the rear of the centre console and two in the dash for anything "portable" and all other 12V accessories are wired directly to a separate 12 V fuse box on the second battery under the bonnet. No loose cables or wires.

Phil

From Jaycar

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There seems to be concern by some people that the efficiency losses of a 12v/230v inverter are to be avoided at all costs. If their mobile stored energy is limited then I can appreciate their concerns. If however, recharging is done on the move as I do then a small efficiency loss is of little consequence and I am saved the cost and trouble of purchasing accessory 12vdc-to-whatever devices to suit each appliance. There can also be compatibility issues with some products, especially if bearing the brand name 'Apple" or "Samsung, when being connected to 'any old' cigar-plug USB charger.
Of course, the efficiency and output quality of inverters is variable by product selection and their benefit is somewhat proportional to their purchase price.

Whilst declaring the transfer losses of an inverter, the losses of the cigar-plug power modules are frequently ignored. In fact, they would also have measurable losses and in the case where the output voltage is required to be higher than 10vdc then they actually incorporate an inverter function to achieve that output. It may be appropriate to actually measure the comparative performance of such devices before advocating their benefit. Often in the case of these products, they employ a simple voltage regulator that drops the 12v input to say 5 volts whilst 'dissipating' the balance of 7 volts thus more power is wasted than supplied.

These small, cheap cigar-plug products employ switchmode technology and being packed into a small package sometimes do not have enough room for components to overcome RFI noise. I have also encountered several instances of product failure of these products which has harmed the connected appliance. In my own case it destroyed a mobile phone which convinced me to use the supplied OEM chargers via a small inverter. The exception is my satphone which was supplied with a 12vdc charger and is powered on at all times.

However, the option of 'inverter' or 'cigar-plug' is a personal decision to suit the specific needs of the user. Neither is 'right' or 'wrong' but it may be prudent to be fully informed before generally advocating either method.

Such passion.
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Lets put a few things in perspective.
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All forms of power conversion have losses, the inverters, the plugpack power supplies and other devices.
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Yes in inverters there are standing losses ( that happen with the thing just running) and conversion losses( that vary with the load drawn).
Putting specific figures on these losses is unreliable ..... they can vary from manufacturer to manufacturer and from unit to unit. ... and how they are expressed.
We can not say that a 300VA inverter will have less losses than a 600VA inverter without some specific information about the specific inverters.
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It may be that one specific 300VA inverter may have more losses than a specific 600VA inverter.
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Unfortunatly the sellers don't always publish standby currents and conversion losses, then there are issues of accuracy.
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I have modest reasonably modern inverters in catalogues that list standby currents in the 200 to 300mA and conversion efficiencies in the 85 to 90%.
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Yes then you have the standing losses and the conversion losses in the 240V power supplies for these units you want to charge ...... the losses there are harder to track down ...... remember too some of these power supplies are over sized for what they are charging so their losses may be higher than necessary.
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It is reasonable to expect efficiencies somewhere between 70% for an analogue power supply and up as high as 90% for a switchmode.
so running a plug pack off an inverter you could easily be looking at combined conversion efficiency as low as 60% pluss standing losses.
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Then we look at the very small amounts of power used to charge many of these devices.
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If we are looking at non standard high current USB, we are talking about 2.1 Amps at 5 Volts ..... total of 10VA. MAXimum, lower current USB may be as low as 500ma at 5 volts 2.5 VA.
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Some of the devices we are charging off USB will be drawing less than the standby current of the inverter.
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So this is most definitely something to consider.
Pretty much If you have devices that charge from USB...... the best potion is a 12 volt USB charger, either plug in or permanently mounted.
That is anything up to a tablet or a full sized camera.
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When we get to laptops things change, most laptops charge off a higher voltage ..... even my little 10 inch charges off 19 volts.
But as mentioned there are specific DC supplies or universal laptop chargers ..... and yes they work.
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They are in them selves DC to DC inverters and can be expected to be about 85 to 90% efficient.
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NOW lets talk about cost ...... apples for apples from the same catalogue.... retail prices.
a 360VA pure sinewave invereter is $339
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A 150 watt universal laptop power supply is $75.
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In this day and age, there is very little reason to introduce 240V into our vehicles.
cheers

I've worked hard at keeping everything 12v but recently had to concede defeat and fitted a 600 w inverter. Its standing loss is said to be 0.45 amps.