Can I run this box fan off these solar panels? [240W Panels > 140W Fan]

wdbatterypax

wdbatterypax

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Hi All!

I'm going camping in a few weeks, and have this box fan I'd love to be able to run during the day when the sun is blazing!

Originally, I thought to build a battery - charge the battery by solar panel and run the fan off the 48V battery. It turns out I won't be able to receive the batteries in time, so I thought maybe I would be able to get decent performance out of the fan just running straight off two solar panels. I understand there is lots of energy loss converting from DC to AC comes with energy loss.

Here are the items I am hoping to use:

Below is the diagram for the setup I hope to achieve. I have heard that I should put some circuit breakers in between the connections.

Thank you!!

1628272572901.jpeg
 
bad idea to run inverter on the solar panels directly without a battery in betweeen. It may work but if you get a cloud or something else the input voltage will jump all around. The inverter is a 48VDC inverter but i cant see the specs on that site. So i guess max input is 60VDC

Those panels give out 34VDC at Vmp and most likely closer to 38+V at max. So thats way above what that inverter will cope with.

ITs better just to connect those 2 panels in series and just connect them to the fan to be honest :) If the fan have a motor that can handle DC that is.
 
Agree with daromer. You need at least a small buffer to stabilize the input.
But you really would want the Solar Panel -> Solar Charge Controller -> Battery -> Inverter.
The Charge Controller make sure to try to keep the panels as efficient as possible
The Battery stabilizes the output so the inverter doesn't since voltage swings especially under loads (turning the fan on, for instance)
 
Never tried without a regulator; direct voltage from panels will vary during the whole day. If your load is only the fan your best choice could have been a DC fan.

But... You have an AC fan.

Inverter can handle variations on voltage, I could bet your specific model (chinese entry level inverter) may not be very tolerant; that's why a regulator is necessary.

Now the problems is that you can't mount cheap regulators (dunno about expensive ones) without a battery.

To mount the system you designed you could add a 10A regulator (a basic true MPPT would be ok); and the smallest 48V battery you can get (even a 4x12V 4A) just to permit regulator to switch on.
 
I built my wife a nice fan using four 12V computer fans in a wood box. It is quiet and works good. You could buy yourself a buck converter and convert the panel voltage down to 12V. Missouri wind and solar does this with a small inverter for pond systems. Although I don't think it works as good as they say. Many inverters lock up with any voltage fault. Solar is a wonderful playground if you know electronics. I run a LG cloths washer off four grid tie panels and an old MSW inverter with a simple modification. NO BATTERIES. Sorry, I know this is a battery centric site. and when it is not washing clothes, it heats water. I wash using hot water in all cycles. No more soap dispenser buildup and the clothes come out steaming.
 
As most buck converters take a wide range of voltage input, this would be feasible. Just don't want to pull too many amps overall as the panel may not be able to compensate for it. Note, I said the panel, not the buck converters. Only an MPPT can make the panel handle current surges effectively.
 
Yeah a DC/DC converter after the solar panel will work fine in most cases. Just beware of how a solar panel works when you take to much from it :) It will drop in voltage like any battery.. See the solar panel as an unreliable battery that will have its moods (Clouds and or night time)
 
daromer said:
See the solar panel as an unreliable battery that will have its moods (Clouds and or night time)
Click to expand...
or leaves or flock of birds.....
 
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