Car inverter power up a monitor with a tvbox

[sdancer75]

Hi,

Is that possible a car 12v to 220v inverter to power up a TV or a monitor with a tvbox set? What kind of problems will I face trying to develop such kind of project ? What if engine shut off power?

[Renate]

I think you probably can.
I'm saying that because I'm sitting here running my desktop computer and monitor off an inverter in my RV.

Two things to consider: How much energy you're consuming in comparison to how much your battery has
and exactly how much current that inverter takes.

A big battery is 80 Ampere-hours, maybe a kilowatt hour.
You don't want to fully discharge your battery.
Also, a starting battery is usually different than a "deep discharge" battery that is designed for such usage.

You want to measure the load to see what kind of performance to expect.

Be sure to connect the inverter on thick cables connected fairly directly to the battery.
Don't use a cigarette lighter unless your load is less than 100W, even then, I'd prefer to wire more solidly.

(Also, I'm running a solar panel here.)

[sdancer75]

how much Watts your inverter outputs? The bigger the better in this case?

[Renate]

how much Watts your inverter outputs? The bigger the better in this case?

Actually, my philosophy is the smaller the better.
Most power converter type thingies are most efficient at some significant part of full load.
So, if you know the maximum power you'd ever use, something in that range would be good.
However, small, inexpensive power inverters can often be pieces of junk with low efficiency.

So, I ended up with a 600W constant, 1200W intermittent.
Bear in mind that that could eat 50-100 Amps!
I'm probably running 100W average.
I couldn't find a decent inverter with less power at the time.

I had considered using a 12V ATX power supply, but I still need AC for tools and stuff.

[sdancer75]

Can you recommend any brands and price range ?

[Renate]

First is to decide if this is a specific use or something open ended.
Will you decide tomorrow that you will also want to run a toaster off this?
Then measure the actual power of what you will be using.

I don't have any real suggestions on brand/price.

The only other decision point is pseudo sine or real sine.
Pseudo sine is usually (for 120V) +/-170V at about 30% duty cycle
Note that usually a single 170V DC supply is internal driving an H bridge.
This means that your neutral is not going to be near ground.
This could be all true for true sines too, but they try to make the voltage approximate a sine more closely.

I just checked my true sine inverter and it measures 60VAC on both neutral and hot.
(Of course those two signals are 180 degree out of phase.)
It looks like the output is floating though.
I have had other inverters that showed 85V DC from neutral or line to ground.
That means that the DC 170V was grounded.

But be careful if you try to feed an inverter somewhere (like a fuse box), the neutral might be grounded somewhere and you'll blow things up.
I have a generator with grounded neutral.
I switch between generator and inverter with two pole breakers.