Thread: 12V inverter calc

What are the voltages to go with the Watts and amps.
I'm guessing the 280 is at 240V, so you need a 280 Watt inverter.
Are you sure the 14 amps isn't 1.4 amps?
240V ÷ 1.4A=171 Watts make sense.
14A÷280W=0.05V doesn't make sense

Tony

Just for the laptop or would you prefer multiple uses? And if so, what would they be?

300w inverter (Pure Sine) would be minimum. for just the laptop.

I need to plug the 20v laptop power brick into an inverter thats powered by 12v storage batteries,
I quite often see 250W draw from the 240v outlet at home..

the laptop has a proprietary power plug so aftermarket power supplies are out..

Originally Posted by Pedro_The_Swift

I need to plug the 20v laptop power brick into an inverter thats powered by 12v storage batteries,
I quite often see 250W draw from the 240v outlet at home..

the laptop has a proprietary power plug so aftermarket power supplies are out..

I=P/V so 250w is only a little over an amp.

regardless, Inverters are quoted (as a rule) by their rated continuous output - so for a sub 300w draw you'll need 300w.
If you want to use it for other purposes rate it up appropriately..

Something from Victron would be my choice
Victron Phoenix Inverter 12/375 230V VE.Direct AU/NZ Socket In Built 8719076033998 | eBay

Hi Pedro, if you have a look at the specs for your “brick” it probably states something like an input AC voltage of 110 to 240vac and 280w.

For a starter, the 280w is the MAXIMUM wattage the device is designed to TOLERATE, not what it operates at. It will be lower than that.

Furthermore, the 280w relates to a 110vac supply voltage and would be about half that for a 240vac supply voltage.

As posted, any 300w 12v to 240 inverter will be fine.

For many years, I use to run my Mac Laptop powered by a Drink Can 175w 12v to 240 inverter and the can never got more than slightly above room temperature.

Add up the wattages of all the things you will be running off the inverter that will be switched on at the same time then use an inverter rated for continuous duty watts above that total load figure.

Also contrary to popular belief most electronics that have a brick type switch mode power supply will happily run on square or modified sine wave inverters or gensets as the brick is filtering noise and converting to DC anyway.

And most devices that plug directly into the AC socket that are stickered 90 - 230 input are switch mode internally anyway so will also happily run on a 'noisy' generator or inverter.