Solar + Batteries = refrigerator use????

[nyone]

It's to hard to say because your fridge cycles on/off. If you want a totally hands off system you need more battery and solar power.

I have a mini fridge running off solar but only when I'm at a weekend cabin. 700w solar, 6 gc2 golf cart batteries.

 

[Boeing]

You really need to head over to diysolar.com. The folks over there can really help you out with this.

To be honest you will not know till you try. There is a loss when going through the AC to DC inverter. You will need to factor in that loss.

I would also invest in this thing called a Killawatt
View attachment 870200

This will tell you just what your appliance is actually pulling in the real world. They are pretty inexpensive.

Mixing 100 and 200W panels does not work quite like you are thinking it will. With solar panels lots of things to learn in the series vs parallel and just what each way does.

You are also going to need a charge controller, this is different from the inverter. It will stop the solar from charging the batteries too high. You will also need some form of low voltage cutoff. Both of these things are very hard on the batteries.

good luck

Alot of variables here. I do have a hi quality controller that all 5 100W are going thru. I have a 2000W inverter that powers most AC things. Yes, I'm sure there is a voltage loss and I'll put my voltmeter on it. That's good advice.
I didn't know that I should not add a 200 panel to 100w panels. I was just "adding" the outputs together.
Thank you

 

[Boeing]

It's to hard to say because your fridge cycles on/off. If you want a totally hands off system you need more battery and solar power.

I have a mini fridge running off solar but only when I'm at a weekend cabin. 700w solar, 6 gc2 golf cart batteries.

Thank you, I'm there about 2 weeks every other month. Are my 5 deep cycles comparable to your batts?

 

[ning]

Get a Victron inverter at the very least. Much higher efficiency, pure sine wave, very low no-load draw.

The one I got - Victron Energy 375VA - can handle a peak load to 700W - should start and run your little fridge just fine.

Computations: going simple and assuming 12V & 120V everywhere. +/- a couple %.

• Fridge supposedly uses 1A @ 120V =~ 120W
• This inverter is max 95% efficiency; assume 90%, so you need about 133W of battery continuous; for one hour that's 133Wh
• Your 750CCA deep cycle battery is likely a 66Ah. If you want to keep the deep cycle from going too deep - let's try to keep it to 50% - that's 33Ah of usable capacity per battery, at 12V = 396Wh
• Assuming fridge is running all the time because kids keep opening it, or you're drinking lots of beer (and forgot to close it?). Theoretically your fridge may only run 1/3 of the time, but you should probably size the system for at least a 50% run time if not higher. The rest of the calcs assume 100%, adjust accordingly.
• One battery at 396Wh gives just under 3 hours of fridge run time
• Five batteries would give a bit under 15 hours (about 2kWh) (at 100% run time; 30h at 50%).
• Typically you shouldn't need nearly 15 hours per day of battery
  • Shorter night, sunny day: batteries don't discharge as much and last longer; fridge is running off of fresh solar while batteries recharge
  • Longer night, dark day: you're glad you have more batteries because you may have dark enough days that you only get 5% of your rated solar power if you're lucky
  • remainder of calcs assuming you have a long night and dark mornings so you go down to 50% on batteries
• Deep cycle battery charging efficiency is about 80%. This means you need 25% more power going into the battery than sticks to it.
• You need to provide at least 2.5kWh from a generator or solar panels to recharge the batteries from 50% so that you hit nighttime with a full charge, keep this going, every day.
• 5 100W solar panels would need 5 hours of full sunlight every day to provide this.
• 5 200W solar panels would need 2½ hours

I set up a much smaller similar independent circuit at a new garden spot on my land because I didn't want to run an overland conduit through my wife's landscaping and extremely rocky ground for garden timers, some lights and other various things (ended up also hooking up an electric fence to the battery directly - it's a 12VDC unit)... could've probably gone pure 12v but it was a fun project - deep cycle battery, 100w panel/trickle charger, started with a $50 amazon 500w inverter but the stupid inverter ate the battery even with no load. The Victron isn't noticeable to the battery and has bluetooth that I can easily see the voltage level of the battery and power usage.

 

[Williy]

For an inverter you want a pure sine wave unit.
Electric motors like them as they will last longer
pure sine wave is basicly like your house electric

Your batteries will last a lot longer is you don't run
them down lower than 80%

I have a 24 volt system and I don't let the batteries
go below 22 volts and my deep ;cycle batteries lasted
approx 16 or 17 years

willy

 

[D'oh]

Mini Fridges use almost as much power as Big Fridges so be careful.

CCA isn't as important as Ah on your Battery Bank.

Refrigeration is the point where most Small Solar Systems become Mid Size Systems. I have tried many ways to make this same jump.

My System.

550W Array
40A PWM Controller (PWM for below freezing temps that the system gets stored in)
690AH of Battery (6, 6V Cart Batteries @ 230Ah each)
2000w Pure Inverter.

So at first I tried a Bar Fridge, only while at the Cabin, Gen Set topping the Batteries during evening hours. Worked but hard on power reserves.

Then went to a small chest freezer, and coolers. Make Ice, take tomorrows supper out the day before, throw it in the coolers, and such. Easier on power reserves and more storage than the Bar Fridge. Even thought of thermostatically turning the Freezer into a fridge, (better insulation) but the Inverter was still the biggest loss.

So now, 12/24V Solar Fridge direct, runs all summer weather being topped up evenings or not. Draws 4.5A@12V while cooling. Compressor kicks in 3-5 time/hour (depending on Door Openings and Temp) for 5 minute/cycle.

Very Happy with the results. Best $ I have spent on the system.

https://www.homedepot.ca/product/unique-appliances-off-grid-19-inch-6-cu-ft-170l-solar-dc-top-freezer-refrigerator-in-white/1001188238?eid=PS_GOOGLE_D29A%20-%20Vendor-Funded_Major-Appliances_GGL_Shopping_PLA_MB_EN_Major%20Appliances_PLA_EN__PRODUCT_GROUP_pla-299507932726&gad_source=1&gclid=EAIaIQobChMIlJ_75-OUhgMVHUb_AR0HEwreEAYYASABEgIdnPD_BwE&gclsrc=aw.ds

Unique's UGP 170L DC solar powered fridge/freezer allows you to enjoy the natural beauty and soundscapes of your surroundings without the never-ending whine and smell of a gas powered generator. Designed for optimal energy savings and easy, dependable use, this 170 L (6.0 cu. ft.) refrigerator boasts a DC compressor and super-efficient insulation with simple effortless controls.

1. Operation: DC Power, 12V / 24V
2. Total Watt. Hr. Draw (24V DC): 520 Wh/ 24 hrs (set to -14C freezer/+4C fridge performance in a +25C ambient)
3. Total Amp. Hr. Draw (24V DC): 19.8 Ah/ 24 hrs (set to -14C freezer/+4C fridge performance in a +25C ambient)
4. Power Consumption: 52 W on 12V/24V - Average Run Current: 4.3A on 12V & 2.2A on 24V Fridge Temp. Range: -4 C to +10°C Freezer Temp. Range: -15°C to -6°
5. Interior LED light - Operational error code warning system - 8ft electrical wire cut end included
6. In-line fuse for protection - Thermostat - 4 heavy duty glass shelves & 3 door shelves - 2 bottom crisper drawers
7. Curbside Shipping: This item will be delivered to your curb or the receiving area of your job site

 

[Williy]

the small 2 door refrig we have draws .96 amps running
our big 2 door frig draws 6.5 amps so I could run 6 of
the small refrig. One time I was going to purchase a 12
volt refrig but when I checked out the amperage draw
decided the 120 cheaper to run. Also the 12 volt frig
I could purchase 2 regular frigs with money left over

willy

 

[nyone]

Mini Fridges use almost as much power as Big Fridges so be careful.

CCA isn't as important as Ah on your Battery Bank.

Refrigeration is the point where most Small Solar Systems become Mid Size Systems. I have tried many ways to make this same jump.

My System.

550W Array
40A PWM Controller (PWM for below freezing temps that the system gets stored in)
690AH of Battery (6, 6V Cart Batteries @ 230Ah each)
2000w Pure Inverter.

So at first I tried a Bar Fridge, only while at the Cabin, Gen Set topping the Batteries during evening hours. Worked but hard on power reserves.

Then went to a small chest freezer, and coolers. Make Ice, take tomorrows supper out the day before, throw it in the coolers, and such. Easier on power reserves and more storage than the Bar Fridge. Even thought of thermostatically turning the Freezer into a fridge, (better insulation) but the Inverter was still the biggest loss.

So now, 12/24V Solar Fridge direct, runs all summer weather being topped up evenings or not. Draws 4.5A@12V while cooling. Compressor kicks in 3-5 time/hour (depending on Door Openings and Temp) for 5 minute/cycle.

Very Happy with the results. Best $ I have spent on the system.

View attachment 870539

https://www.homedepot.ca/product/unique-appliances-off-grid-19-inch-6-cu-ft-170l-solar-dc-top-freezer-refrigerator-in-white/1001188238?eid=PS_GOOGLE_D29A%20-%20Vendor-Funded_Major-Appliances_GGL_Shopping_PLA_MB_EN_Major%20Appliances_PLA_EN__PRODUCT_GROUP_pla-299507932726&gad_source=1&gclid=EAIaIQobChMIlJ_75-OUhgMVHUb_AR0HEwreEAYYASABEgIdnPD_BwE&gclsrc=aw.ds

I have less than that DC fridge costs into my whole system including a 4.3cuft fridge and 1kw inverter generator. The only thing I bought used was a inverter.

Dont buy DC appliances for the power savings when you can add quite a bit more solar capacity and use standard cheap 120v appliances for less money.

 

[nyone]

the small 2 door refrig we have draws .96 amps running
our big 2 door frig draws 6.5 amps so I could run 6 of
the small refrig. One time I was going to purchase a 12
volt refrig but when I checked out the amperage draw
decided the 120 cheaper to run. Also the 12 volt frig
I could purchase 2 regular frigs with money left over

willy

Family has a RV with a electric/propane fridge..that thing is such a power hog it draws as much as my full sized double door fridge with ice maker. Cost prob 3x too.