Running 90watt 12/24v dc fridge direct from solar panels?

[Smeeg]

Hello I’m trying to see if it’s possible to run a 12/24v dc mini fridge uses 90 watts no spike when the compressor turns on directly from solar panels. I’m thinking two 100 watt solar panels & some kind of buck transformer to make the power more stable?
Any help Innsite would be appreciated.
I know it would be better to use a battery & charge controller I just want to see if it’s possible for fun

Also since it can run on 12-24vdc do I need a step down converter to make the voltage more “stable” ?

12v Solar without a Battery

If you have a small 12v appliance that you wish to power/charge when the sun is out, you can use a 24v\36v to 12v step down converter. This will modulate the power produced by your solar panel into a...

www.mobile-solarpower.com

Wills write up^

 

[timselectric]

All that you can do is try. If two isn't enough. Just add more until it is.

 

[squowse]

Hello I’m trying to see if it’s possible to run a 12/24v dc mini fridge uses 90 watts no spike when the compressor turns on directly from solar panels. I’m thinking two 100 watt solar panels & some kind of buck transformer to make the power more stable?
Any help Innsite would be appreciated.
I know it would be better to use a battery & charge controller I just want to see if it’s possible for fun

12v Solar without a Battery

If you have a small 12v appliance that you wish to power/charge when the sun is out, you can use a 24v\36v to 12v step down converter. This will modulate the power produced by your solar panel into a...

www.mobile-solarpower.com

Wills write up^

what makes you say "no spike". How does the compressor motor not require a surge of current to start it?

 

[Smeeg]

what makes you say "no spike". How does the compressor motor not require a surge of current to start it?

It has a digital or scroll compressor so it slowly ramps up & down

 

[Doggydogworld]

Hello I’m trying to see if it’s possible to run a 12/24v dc mini fridge uses 90 watts no spike when the compressor turns on directly from solar panels. I’m thinking two 100 watt solar panels & some kind of buck transformer to make the power more stable?
Any help Innsite would be appreciated.
I know it would be better to use a battery & charge controller I just want to see if it’s possible for fun

Also since it can run on 12-24vdc do I need a step down converter to make the voltage more “stable” ?

12v Solar without a Battery

If you have a small 12v appliance that you wish to power/charge when the sun is out, you can use a 24v\36v to 12v step down converter. This will modulate the power produced by your solar panel into a...

www.mobile-solarpower.com

Wills write up^

12/24s often have an internal auto-switch, they can't necessarily handle any random voltage. That said, systems designed for cars and trucks don't require a rock-sold 12V (or 24V), either. Car voltages vary from 14-15V when the alternator is running to a bit over 12V with the engine off.

A 100W 12V panel will usually be low 20s Voc and maybe 17-18 Vmp. But voltage can be much lower in cases of partial shading or a low resistance load. Your fridge probably has protection for over/under voltage, but I wouldn't push my luck too much on that by connecting a panel directly to it.

I'd prefer a converter that can put out a steady ~13V over a range of input voltages. The converter / panel side of things is still open loop, so it may require some experimentation to get things working. But as long as cold temp Voc doesn't exceed the converter's max rating failures should be of the "fridge doesn't run" variety vs. a magic smoke release.

 

[Smeeg]

12/24s often have an internal auto-switch, they can't necessarily handle any random voltage. That said, systems designed for cars and trucks don't require a rock-sold 12V (or 24V), either. Car voltages vary from 14-15V when the alternator is running to a bit over 12V with the engine off.

A 100W 12V panel will usually be low 20s Voc and maybe 17-18 Vmp. But voltage can be much lower in cases of partial shading or a low resistance load. Your fridge probably has protection for over/under voltage, but I wouldn't push my luck too much on that by connecting a panel directly to it.

I'd prefer a converter that can put out a steady ~13V over a range of input voltages. The converter / panel side of things is still open loop, so it may require some experimentation to get things working. But as long as cold temp Voc doesn't exceed the converter's max rating failures should be of the "fridge doesn't run" variety vs. a magic smoke release.

That’s what I was thinking that it wouldn’t like the voltage fluctuating
What do you think of this converter/regulator

https://www.amazon.com/Kohree-Converter-Regulator-Transformer-Waterproof/dp/B09GXXQZ6P/ref=mp_s_a_1_5?crid=RPVSRX18YYU8&keywords=24v+dc+to+12v+dc+converter&qid=1677872961&sprefix=24v+dc+to+%2Caps%2C87&sr=8-5

 

[Doggydogworld]

That’s what I was thinking that it wouldn’t like the voltage fluctuating
What do you think of this converter/regulator

https://www.amazon.com/Kohree-Converter-Regulator-Transformer-Waterproof/dp/B09GXXQZ6P/ref=mp_s_a_1_5?crid=RPVSRX18YYU8&keywords=24v+dc+to+12v+dc+converter&qid=1677872961&sprefix=24v+dc+to+%2Caps%2C87&sr=8-5

One customer reviews says:

1) though it converts to 12 volt DC, there are a lot of 12-volt devices that prefer 14 to 15 volts in order to work properly, and this device provides me less than 13 volts, which constantly leaves my 12 volt devices thinking that the battery is low or dead, and for some of my devices, including my portable refrigerator, the display works but the refrigerator does not because it is in low battery mode.

Also it says the input can range from 18-35V. The 35V gives you plenty of headroom, but it's pretty easy to get a "12V" panel to drop below 18V, especially when it's hot. I'd try to find one that outputs 13-14V and will work with input voltage down to 15V or so. Not sure such a beast exists.

 

[Smeeg]

One customer reviews says:

1) though it converts to 12 volt DC, there are a lot of 12-volt devices that prefer 14 to 15 volts in order to work properly, and this device provides me less than 13 volts, which constantly leaves my 12 volt devices thinking that the battery is low or dead, and for some of my devices, including my portable refrigerator, the display works but the refrigerator does not because it is in low battery mode.

Also it says the input can range from 18-35V. The 35V gives you plenty of headroom, but it's pretty easy to get a "12V" panel to drop below 18V, especially when it's hot. I'd try to find one that outputs 13-14V and will work with input voltage down to 15V or so. Not sure such a beast exists.

Maybe I should go with something like this and wire the panels in series but that doesn’t help that 12v output might be too low

https://www.amazon.com/gp/product/B07J274LZD/ref=as_li_ss_tl?ie=UTF8&psc=1&linkCode=sl1&tag=vehicledwelling-20&linkId=b8082be45e9c266e1d32dd83d3ce30a2&language=en_US

 

[Doggydogworld]

Yeah, the fixed 12V units seem designed for light bars and such. Your fridge might be OK with 12.0V, or might not. I believe the low voltage cutoff is designed to prevent the fridge from draining your car battery too low while you're off surfing or whatever. Better to return and find warm beverages than to get stranded.

The Victron Orion-TR 24/12-9 lets you adjust output from 10-15V, but comes with that expensive blue cover. If going with fixed output I'd shoot for a 13.8V unit. Nice wide 9-36V input range, too.

 

[squowse]

It has a digital or scroll compressor so it slowly ramps up & down

Interesting. Never heard of that. Is that your own custom build or a production model? Which manufacturer?

 

[Smeeg]

Yeah, the fixed 12V units seem designed for light bars and such. Your fridge might be OK with 12.0V, or might not. I believe the low voltage cutoff is designed to prevent the fridge from draining your car battery too low while you're off surfing or whatever. Better to return and find warm beverages than to get stranded.

The Victron Orion-TR 24/12-9 lets you adjust output from 10-15V, but comes with that expensive blue cover. If going with fixed output I'd shoot for a 13.8V unit. Nice wide 9-36V input range, too.

Awesome find thank you think 10amps is good?

 

[Tecnodave]

All 3 of my DC powered fridges work on 10-15 v.d.c or 20-30 v.d.c. or 90-130 v.a.c. The controller auto selects proper input

The motors in the compressor is DC permanent magnet with exiter coils in a 3 phase arrangement controlled by the logic control board.

This is exactly the same arrangement of coils/magnets found in electric bicycle wheels....

Danfoss of Holland developed the dc powered compressor. Mine are Asian clones.

Even the 5 cu.ft. ones will work on one 100 watt panel and one 100 a.h. lead acid battery without varing temperature