Inverter capacity

[dochiley]

I have a tiny inverter (I think) - it says 150W.
I need to use it to charge computers and such (not hairdrier or microwave!!) so how big do I need it and has anybody got a "best buy" suggestion?
Your help and sharing of experiences will be most gratefully read.

 

[pappajohn]

Look at the power requirements in input watts on the computers power supply.
Do the same for all other appliances and total them up.
Double the total, that's the wattage of inverter needed.
By doubling it will run cooler and longer without alarming.
BUT...... most low voltage things, including laptops, can be charged from a 12v supply with the correct chargers.

 

[Kannon Fodda]

Chargers for computers can be quite sensitive to the right type of power. Go for a pure sine wave inverter, not modified.

As for the power needed, your charger for the computer should state it's input need. My quite beefy laptop states 100-240V 2.34A. Online calculators show that is between 234W at 100V but up to 561W at 240V. The output is 9.23A at 19.5V or 180W. So the charger looses power from inefficiency. And your inverter would do the same so you also need a bit of headroom. In my case I'd need an inverter rated at minimum 600W, and ideally a bit larger.

But then is your leisure battery capable of supporting such a draw?

 

[Misterg]

My quite beefy laptop states 100-240V 2.34A. Online calculators show that is between 234W at 100V but up to 561W at 240V. The output is 9.23A at 19.5V or 180W. So the charger looses power from inefficiency. And your inverter would do the same so you also need a bit of headroom. In my case I'd need an inverter rated at minimum 600W, and ideally a bit larger.

I think your do your charger a disservice - it will only draw the marked current at the lowest input voltage - it will draw a bit over 200W regardless of input voltage if it's rated at 180W output -234W doesn't sound unreasonable, so an inverter to power it only needs to be rated at (say) 250 or 300W continuous.

dochiley - as PJ suggests, have a look at the rating on your chargers. I wouldn't be surprised if they were less than 150W.

The Victron Phoenix inverters are good quality for the money:

Inverter VE.Direct - Victron Energy

Inverters allow you to power domestic equipment - requiring 230V/120V AC - using 'leisure' or 'automotive' batteries rated at 12V, 24V or 48V DC.

www.victronenergy.com

 

[peterc10]

Every laptop I have had in the last 20 years did not go anywhere near mains elecricity. All had external converter blocks and turned the 240v AC into low voltage (from 12v to 21v depending upon make) DC, which then fed the laptop via another cable. All this can be done more easily and efficiently by using 12v DC in the first place. That is why I always use 12v adapters for my laptops when I am on the move and I have never had any problems with them.

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[dochiley]

That's interesting - what is the point of inverting up to 240V and then transform back to low voltage.
As suggested I have looked at what voltage comes out of my computers transformer that attaches to the 240V supply. The transformer for a Microsoft Surface says 15V and one for my Dell says 19.5V and that for our MacBook says 14.5V.
So 'one size will not fit all' and that is perhaps why you go up o 240V and use the charger that comes with the computer - which will be giving what volts it needs.
However, where does one get/buy a 12V gizmo that will increase output voltage slightly to give 15 or 19V? Anybody know?

 

[dochiley]

PS - Peterc10 - Thanks for your input. If you "always use 12v adapters for my laptops when I am on the move and I have never had any problems with them" - what is the voltage needed for your computer and where did you get the 12V adapter?

 

[peterc10]

PS - Peterc10 - Thanks for your input. If you "always use 12v adapters for my laptops when I am on the move and I have never had any problems with them" - what is the voltage needed for your computer and where did you get the 12V adapter?

My previous HPs were about 19V from memory. I now have a Microsoft Surface Pro, which is 12v. But remember that the 12v in the moho is always higher than that, so you still need an adaptor..

I buy one from Amazon that is specific to my laptop. I used to buy them even before we got a moho, because I sometimes needed one for the car. Just search using the make and name of your computer plus the words "12v adaptor" or "car charger"

 

[Off da Grid]

go for 12v converters as said above much more efficient, some have multiple voltage and and pin types.

 

[PhilandMena]

300 W pure sign wave does my lap top without a problem.

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[dochiley]

Thanks guys. I have found this

12V/15V/16V/18V/19V/20V/22V/24V 120W Max Universal Adapter Charger Power Supply | eBay

Find many great new & used options and get the best deals for 12V/15V/16V/18V/19V/20V/22V/24V 120W Max Universal Adapter Charger Power Supply at the best online prices at eBay! Free delivery for many products!

rover.ebay.com

and this

Universal AC/DC to DC Adapter Inverter Car Charger Power Supply for Laptop a8 | eBay

Find many great new & used options and get the best deals for Universal AC/DC to DC Adapter Inverter Car Charger Power Supply for Laptop a8 at the best online prices at eBay! Free delivery for many products!

rover.ebay.com

either seem likely to adjust to do the job.... provided the pins that come match up with the computer. However, it will certainly not match up to the Microsoft Surface!

 

[peterc10]

Thanks guys. I have found this

12V/15V/16V/18V/19V/20V/22V/24V 120W Max Universal Adapter Charger Power Supply | eBay

Find many great new & used options and get the best deals for 12V/15V/16V/18V/19V/20V/22V/24V 120W Max Universal Adapter Charger Power Supply at the best online prices at eBay! Free delivery for many products!

rover.ebay.com

and this

Universal AC/DC to DC Adapter Inverter Car Charger Power Supply for Laptop a8 | eBay

Find many great new & used options and get the best deals for Universal AC/DC to DC Adapter Inverter Car Charger Power Supply for Laptop a8 at the best online prices at eBay! Free delivery for many products!

rover.ebay.com

either seem likely to adjust to do the job.... provided the pins that come match up with the computer. However, it will certainly not match up to the Microsoft Surface!

I personally would never use a multi adaptor. There are so many types of connectors and their polarity that you are always dicing with disaster. Nor would I use ebay, too many dodgy dealers. The thought of spending less than £11 to get a decent adaptor for all of those different types and voltages would fill me with dread.

A quick search of Amazon using the phrase "Microsoft Surface car charger" finds plenty of ones for you to look at.

 

[dochiley]

Thanks guys for the advice. Bought 12V chargers for the Mac and the Surface (as they can be identified as being 'different' and correct) one from EBay and one from Amazon. So ready for anything now!