ikw777 said...

Can anyone tell me what sort of power inverter I should get for my car so I can charge my table, phone, and camera while I'm travelling? Do you need to spend a lot on these or do the cheap ones work OK?

Not sure what type of table you are charging? Microsoft's Surface, as ingenious as it is, is not exactly portable... (note video below)



In any case, if you do need to charge your table on the road you'll need a big ass inverter and a trailer...

200w is fine for charging those devices.

For any USB charged devices, except for Apple stuff, I found that you can use a USB cigarette lighter adapter. A lot of devices don't charge that well from these because the standard only supplies a small amount of power by default.

What I did find though, was that if you plugged a USB 3 hub into the USB cigarette lighter adapter, it would charge things much faster. Plus it gives you 4 ports to charge 4 devices.

I know, nerdy, but it means I can charge most phones, tablets, and anything else that takes USB charging, in the car, fast.

Apple products seem to have their own standard of charging, so you are better off with specific apple chargers.

My Laptop power supply is only 65W, so I am assuming that a 100W inverter would be fine. Jaycar sell 12v car Laptop chargers. Some laptops won't work with them because the power supply talks to the charger, but you could always take your laptop into them and see if they can try it.

Of course, an inverter and the normal chargers are simpler.

As already stated, if you can use USB adapters then they're the easiest. The USB standard allows for a max of 500ma of current draw at 5v. That's 2.5 watts. That doesn't mean that any manufacturer can't do his own thing, but standards are better

The standard for an automotive ciggy lighter is a max current draw of 10a at a nominal 12v. That's 120watts.

Inverters are not all that efficient - especially the cheapies, which, as stated, have some seriously ugly output waveforms. Again, as already stated, that shouldn't worry most switch-mode power supplies. BUT it can completely destroy some sensitive equipment which requires a sine wave input. eg most common CPAP machines.

So, if you're going to use an inverter run from your ciggy lighter you're most likely only going to have about 100watts of power available for your chargers. A larger inverter run directly from your battery (with appropriate sized wiring and fuse) would give you more flexibility.

I run this one on the d4d hilux..I asked the electricians at work and he said this would be sufficient.


http://www.jaycar.com.au/productView.asp?ID=MI5104


( the better model 600 watt) Porbally use duel battery with it.
www.jaycar.com.au/productView.asp?ID=MI5164


You will have to check the power your lap top consumes mine is under 300 watts. Perfect for phones and computers.
They power usage should be on the laptop charger . Find out what you consuming and get one rated above.


More than that i dont believe that a shark sheild can be charged of it. I plugged my mates freedom 7 into it and it went spastic ( freedom 7 replaced his sheild no questions asked. They have extremely good PR


Freedom 7
* 7 hour rechargeable Nickel Metal Hydride battery pack
* 100-240V battery charger _ dosent show watts????????????
* 12V adaptor for battery charger
* Neoprene pouch
* Product Instruction Bookle

FormulaNova said...

Mark _australia said...
Chargers draw stuff-all current - 1000W is for like a small kettle or camping toaster etc. Check your devices, but I can't see them drawing more than a couple hundred watts so the cheapies would be fine.

But only for charging - don't use the device off a cheap inverter, too risky

In theory, there should be no difference between running the device off of the inverter while it is charging, as long as you cover the requirements of the powersupply.

Cheap inverters are square wave, but with a lot of devices using switch mode power supplies these days, you probably wont have a problem. If the original charger is heavy, its probably not a switch mode power supply. Some of these old type power supplies heat up more when using a cheap inverter, but a laptop power supply shouldn't perform any different.

In theory that is great.
But if buying a $20 inverter unit...... I'd rather charge it then unplug it from the cheapo inverter THEN use it, rather than risk my $3K laptop. ie just wait half an hour!

It was not a definitive reply - just a warning that what may *charge* a unit that is turned off may not be good enough for continuous *use* of a unit that is turned on.

My vibrating artificial vagina is now useless and I regret even going on the camping trip to Ibiza
Personally I think IKW may need to disconnect and chill.

One of my mates is a sparky, he has the best set up I have seen. Runs dual battery charged from the alternator, his inverter has him wired with 240v plugs in the back of the ute and in the cab that he uses to power tools via lead and charge batteries for drills and other tools as well as his computers and phones.

It's kind of expensive but his car is literally a rolling workshop and office.

Great for camping as well for fridges, microwaves, TV's etc.

Not sure on brands was suitably impressed by his demonstration.

my 2 cents . . . .
inverter technology has evolved so much over the last five years - so price alone is not the best measure of quality. . .

so the short answer yes the a lot of cheap ones work great ... and can be found online for very little money

some shops are still selling less efficient inverters with a square sine wave for three or four times the price you can get a pure sign wave inverter for

the long answer . . . . .

if its anything electronic (especially tablets and laptops) go for a pure sign wave inverter to protect your investment - yes it will in most cases work on a sqaure sine wave but it's like running your expensive car on moonshine it will work but what damage is it doing along the way
. . . . . your looking for an efficiency in the 80 - 85% range as that's basically where they are at the moment some claim higher efficiency but that is either bullsh!t or your gonna pay a hell of a lot for the privilege and it still may be lies

finally the efficiency is only really relevent if you are using the inverter to it's capacity eg:

you have an inverter capable of 1000 watts but all your doing is charging your tablet i even though it states a 80% efficiency you will get nowhere near this when using such a small amount of its rated power so you will be using heaps of power to get very little out

if you were looking to be a bit more serious about it and spending more money now or later on then it would be ideal to own two inverters get one smaller 50 - 300 watt pure sine wave inverter for the electronic stuff
and get a larger one for higher current draw equipment this would ensure a more efficient power management while camping fishing etc (hours more battery life)

also as has already been mentioned the most efficient way of powering dc off a car is a dc to dc transformer losses are almost not worth mentioning but the problems that you can have from this method is that the transformers are directly affected by fluctuations in your cars electrical system (even the interior light if you keep opening doors etc) so to protect the equipment it is best to install a power stabilizer directly before the transformer ( a sort of dc-dc inverter)

hope this helps

how are you hooking up your inverter. car cigarette lighters are fused so there is a limit to how much current you can draw regardless of your inverter wattage. ie. not much point buying a 1000w inverter if your going to use your cigarette lighter connection.

anything higher than what the fuse can handle and you need to connect directly to your battery and that's a whole other setup which you would want an auto electrician involved.

that said, most electronic gear is 12v dc or less so you don't need an inverter for that.

check on the back of your gear and see what the power requirements are. you will only need an inverter in cases where more than 12v (cigarette lighter) gear is involved. like laptops.

cheapest option is the cigarette lighter in your car. either via your electronics gear cigarette lighter conection or via a 12v to 5v usb/cigarette lighter adaptor for usb powered gear.

or, jaycar sells 5 in 1 jump starter, inverter portable unit.

or just make your own with a car battery, some jumper leads and a diy 12v-cigarette lighter cable. add in an inverter and solar cells if you want.

beats running your car battery flat.

yeah the first response is somewhat a valid point a lot of the electronic equipment i have used over the years is 230v ac in and yes i have had problems with square sine wave inverters

just one example : a lot of the big brand industrial lipo battery chargers will not run on them at all and some when they do have and will burn out.

i have seen multiple failures on power supplies including laptop ones that i have "assumed" was down to the nasty square sine wave inverter but i have no proof other than an almost non existent failure rate from friends using pure sine wave inverters - read what you want into this

as for the second point read my post again "dc to dc transformer"

ratio of windings = ratio of input to output voltage

a cars electrical system voltage fluctuates between 10- 15 volts a lot of the time due to many reasons yes i have seen and investigated this with all sorts of data logging test equipment and fitted voltage regulators to some vehicles to overcome this problem
this is not a cheap solution but extends the life of the equipment by a long way

sorry if this doesn't match up with your life experiences but im sure ill get over it

airjunkie said...
yeah the first response is somewhat a valid point a lot of the electronic equipment i have used over the years is 230v ac in and yes i have had problems with square sine wave inverters

just one example : a lot of the big brand industrial lipo battery chargers will not run on them at all and some when they do have and will burn out.

i have seen multiple failures on power supplies including laptop ones that i have "assumed" was down to the nasty square sine wave inverter but i have no proof other than an almost non existent failure rate from friends using pure sine wave inverters - read what you want into this

Interesting. I can't say I have actually used any switchmode supply on a square wave inverter for any decent length of time, so I can't say much about it other than in theory it shouldn't be a problem. Sometimes though, there are other things that get in the way

I can understand a regular transformer having problems though. Regular transformers are getting rarer and rarer these days as switchmodes have become so cheap.

I remember the days when TVs had big heavy transformers.

as for the second point read my post again "dc to dc transformer"

ratio of windings = ratio of input to output voltage

a cars electrical system voltage fluctuates between 10- 15 volts a lot of the time due to many reasons yes i have seen and investigated this with all sorts of data logging test equipment and fitted voltage regulators to some vehicles to overcome this problem
this is not a cheap solution but extends the life of the equipment by a long way

sorry if this doesn't match up with your life experiences but im sure ill get over it

I don't know what a DC to DC transformer is. In normal 12v car chargers they don't use them. These are regulated, and as the technology is so cheap, it would probably cost more to do it unregulated. This automatically takes care of any variations in power supply.

Its good to see other's experiences though, so don't take this the wrong way.

a transformer can be used as a dc to dc converter. as can an inductor.

anyways, the point of using a transformer other than step up or step down properties is the isolation it provides.

now i am in over my head.

Gestalt said...
a transformer can be used as a dc to dc converter. as can an inductor.

anyways, the point of using a transformer other than step up or step down properties is the isolation it provides.

now i am in over my head.

No, the transformer can't be used as a dc to dc converter, but a dc to dc converter can use a transformer. Transformers can only be used when the magnetic flux is changing, and DC doesn't do that. Even an inductor needs to have DC modulated some way, so its AC anyway.

You can get (auto) transformers that share a common and provide no isolation, but I think you know how this stuff works anyway.

I'll back out now before people start shooting holes in my understanding...

yes but if the dc is pulsing it does.

Ian K said...
Any repeating wave, square, triangular, the ugliest waveform you can imagine, can

Sounds like you did your electronics way back when I did Dinsdale. They don't seem to use regulators like that anymore, energy is precious. From what I can gather the switch mode regulators work by tapping current into one end of an inductor at high frequency by switching the supply. Then I suppose the tapping frequency is regulated to make sure the load at the other end of the inductor has the specified voltage across it? Anybody found a simplified circuit diagram of one? Must be a diode or two involved - they still use diodes don't they?

Hate to scare you Ian, but they still use three-terminal regulators when the price matters. Who cares about efficiency when the user only cares about price.

Switchmodes can have variable frequency, variable pulse width, or a combination.

Silicon Chip (the magazine) has a few DC motor controllers that use switching designs to reduce motor speeds. Not quite the same as a regulated switching power supply, but they do use the same IC in the same fashion.