Could you use Solar to power a DC to AC Inverter? (Description below)

[amazingjoe]

TL;DR Summary

I am interested in having an AC outlet that can be powered by Solar. I am curious if I could use a simple and cheap DC Car Power to AC Inverter and rig the Positive / Negative leads from the Panels to the cigarette adapter. (More specific details provided below)

I'd like to take Solar Panel power output and use it to power an AC outlet on the ultra-cheap. I know a lot of people use Solar to connect to a purpose built inverter and also have a battery somewhere in the mix to provide a stable output but wondering if the following (using the assumptions below) is a possibility and if the results in more or less nominal conditions would likely be satisfactory.

Assumptions:

• Panels can be purchased (or built) to whatever the nominal output in Voltage and Amps is for the specified inverter.
• We would use a super cheap ($15) commercial car DC to AC converter shown here: Amazon Link to Converter and aim to disassemble the CAR DC connector and attach the Solar Positive/Negative to the positive/negative wires in the DC connector.
• I would like to be able to power non-high powered devices that would normally be suitable and recommended for the inverter. For example a small LCD TV that perhaps draws 18 watts.
• The device would only function consistently well when the sun light was close to nominal conditions (i.e. It may brown out when a cloud covers the sun or the panel is partially or fully in the shade or any other condition that would cause the panel to produce low amounts of power that may not be sufficient for the amount of power the device connected to the outlet may be trying to pull from the inverter.

Question(s):

1. If you have Voltage and Amperage output that does not exceed the threshold that the inverter could handle should this work in theory (attaching leads from Solar + / - directly to the DC car connector +/- terminals)
2. When the sun is shinning and the panels are producing nominal amounts of power would a supported device like a TV be able to run assuming there is no battery attached etc... to draw power from?
3. If there is nothing in place to eliminate dips in power (i.e. No batter backup) would a device like a small television that is unable to draw the amount of power it needs (i.e. Say power dips below 18 watts for a TV that draws 18 watts) for sustained periods of time would it potentially damage the electronic?

If I can have a panel that can safely (and mostly reliably when the sun is out) power electronics without a high risk of destroying the electronic I think this would be a super cool project. Solar panels can be super cheap depending on how you source them and this inverter is so cheap I have dreams of creating a cheap panel I can stick in a sunny area in the yard or even on top of an outside umbrella and running a tiny TV and maybe even a USB fan off the solar. All without a battery to save on costs.

Is this a worthwhile venture or not going to work out as I have outlined it?

 

[artis]

If you can find a solar panel with a 12v output then sure you can attach it to the input of an inverter and it will work. Without battery storage though your inverter will only provide output power that is proportional to input power. If your output load will surpass the power of the solar panels at the inverter input you will either see a sag of voltage at the output or the inverter will shut down depending on the type of inverter and it's safety circuitry.
So yes you will be able to watch your TV until either the sun drops below a certain threshold or some other factor causes the inverter to lose power.
For simple things it doesn't matter, like cell phone chargers etc, as for a TV I don't know , hard to say.

A general rule of thumb is that electronics like stable power but that also depends on the type of appliance , like for example a water heater coil doesn't care whether you pulse the power or not.
A laptop also might not if it has a good battery.
Either way if you can find such panels and they suit you why not, go ahead.
Also I think there might be some cheap 12v Li-ion battery packs that can be plugged in and form the storage component. Those packs normally come with their own charge regulator built in so you don't have to worry about overcharging them.

 

[anorlunda]

So yes you will be able to watch your TV until either the sun drops below a certain threshold or some other factor causes the inverter to lose power.

Such as a cloud passing overhead. To avoid dropping the TV when clouds pass, you could oversize the solar panel. For example if the TV needs 100 watts, then size the panel for 400 or 500 watts. That way, it may still make 100 watts when a cloud passes. On days when the overcast is thick, it may be difficult to make your inexpensive solar solution work.

 

[Tom.G]

Try this search: (I chose 35W because panels are rated by peak power)
https://www.google.com/search?&q=panel+solar+35w+12v

You may actually need 70W to 100W to power an inverter, they draw high peak currents.

There used to be TVs that would run on 12Vdc, they probably still exist for mounting in a car for back-seat passengers to watch.

Cheers,
Tom

 

[artis]

Such as a cloud passing overhead. To avoid dropping the TV when clouds pass, you could oversize the solar panel. For example if the TV needs 100 watts, then size the panel for 400 or 500 watts. That way, it may still make 100 watts when a cloud passes. On days when the overcast is thick, it may be difficult to make your inexpensive solar solution work.

Exactly , this is why solar takes up a lot of space because in order to have steady power one needs not just some storage to fill in the gaps but also some reserve because the sun isn't always at 5 degree angle and at full power.
@amazingjoe Now I haven't searched the panels that much but I would think that you would need at least one typical panel that has an output rating in the 300-400w range, especially if you plan to not use any storage because as @anorlunda said having your solar panel barely match the power you are using will mean that every time a cloud passes you might experience a "blackout".

 

[Borek]

Note: as long as voltages are correct, there is no risk that the high power panel with nominal current output far exceeding your inverter needs will destroy it. Inverter has an internal resistance and will just draw as much current as it needs, that's Ohm's law at work.

 

[solvejskovlund]

(Late reply, but hopefully still useful to someone)
Connect a dc-dc step-down converter between the panels and the 12v input of the inverter. Adjust it to 12v. I paid about $2,50 incl shipping for my 200w converter a year ago. It accepts input in the range [output voltage]-60V. Output is adjustable from 1-60V. I also have a 100w converter that accepts up to 90v input. There are more powerful converters available, but they are more expensive. Bought them at aliexpress.
We're off grid. I ran inverter directly off the solar to power the tools used to build the first batterypack. It works, but you should not consider it a stable power source, unless you have clear sky.