Want to build system to run fridge

[rjmetals]

Hi everyone,
Lets start out by saying I'm a solar dummy. Looking to build an small emergency system to run home Samsung refrigerator/freezer (AC115V/60Hz 5.3A) in sunny Arizona when grid goes down. Thinking of 3000w pure sine wave inverter with 40A controller, 2x 12V batteries. Will this work in 12v or do I need 24v system? Do I need more batteries to make this work? What PV panels are needed? Thanks for any suggestions you can offer. Never built a system before. Sorry, don't know much. RJ

 

[dmholmes]

Hi everyone,
Lets start out by saying I'm a solar dummy. Looking to build an small emergency system to run home Samsung refrigerator/freezer (AC115V/60Hz 5.3A) in sunny Arizona when grid goes down. Thinking of 3000w pure sine wave inverter with 40A controller, 2x 12V batteries. Will this work in 12v or do I need 24v system? Do I need more batteries to make this work? What PV panels are needed? Thanks for any suggestions you can offer. Never built a system before. Sorry, don't know much. RJ

My fridge label was pretty meaningless in calculating the load. A watt meter will help you figure out how much power it uses to startup and run.

 

[rjmetals]

My fridge label was pretty meaningless in calculating the load. A watt meter will help you figure out how much power it uses to startup and run.

I have one.

 

[dmholmes]

I have one.

How much is it using on startup and running?

 

[rjmetals]

I have one.

 

[rjmetals]

How much is it using on startup and running?

Haven't used the meter yet.

 

[snoobler]

I have one.

Install it, use it for 7 days. Fridge must have contents similar to what would normally be in it, and it should be opened and closed several times a day simulating use.

Note the total kWh consumed.

Divide by 7 and add 360. That's your daily kWh need (the 360 is the power the inverter will consume - 15W est).

Divide daily kWh need by 3.33h, that's the amount of of solar you need.

Multiply daily kWh need by 2, divide by 12V, that's the amount of Ah you need to run it for 24 hours.

Example:

2000Wh daily need.
600W solar
333Ah of lead-acid battery storage.

Tidbits:
12V is fine.
600W /12V = 50A - you need a charge controller capable of delivering this current.
1500-2000W inverter should be fine. If you get an inverter that's too large, the inverter itself will consume a substantial portion of the power needed.

 

[Bud Martin]

"1000kWh daily need."
Is that a typo?

 

[rjmetals]

Install it, use it for 7 days. Fridge must have contents similar to what would normally be in it, and it should be opened and closed several times a day simulating use.

Note the total kWh consumed.

Divide by 7 and add 360. That's your daily kWh need (the 360 is the power the inverter will consume - 15W est).

Divide daily kWh need by 3.33h, that's the amount of of solar you need.

Multiply daily kWh need by 2, divide by 12V, that's the amount of Ah you need to run it for 24 hours.

Example:

2000kWh daily need.
600W solar
333Ah of lead-acid battery storage.

Tidbits:
12V is fine.
600W /12V = 50A - you need a charge controller capable of delivering this current.
1500-2000W inverter should be fine. If you get an inverter that's too large, the inverter itself will consume a substantial portion of the power needed.

Thanks!

 

[SalckwareRobert]

"1000kWh daily need."
Is that a typo?

No that's a vegas casino. LOL
It does explaion the need for solar. The power company it tired of replacing meters when the wheel keeps flying off spinning to fast.

 

[rjmetals]

To Moderator: Why, in your steps, do I need to divide kWh by 3.33h? What is the 3.33h? Is that amount of sun hours? Thanks!

 

[AZRoadrunner]

RJ - I'm also in Arizona and recently built a solar power "cart" for emergency use in the house. The finished system has two Battleborn 12v LifePo4 batteries in parallel, and uses a Victron 100/30 charge controller. I use three 195W panels wired in series and mounted them up on top of the ramada covering our back porch, facing due south. The inverter is a 2 kW pure sine wave, and can also charge the batteries if plugged into grid power. Everything is built into an audio-visual cart on wheels. I've tested the system on just about everything in the house, including our full-size refrigerators, and it runs most anything with ease. It will even run a portable room air conditioner for about two hours. The system also includes a Victron battery monitor, which allows me to see real-time how much juice is flowing when the cart is in use. When powering a modern refrigerator, the current draw varies quite a bit as the appliance moves through various cycles -- I ran our full-size refrigerator in the kitchen on the cart for a few hours one day just to see how it went, and it appeared that I could get about 5 or 6 hours out of the cart before depleting the batteries. Honestly, our vacuum cleaner pulls more power than the fridge. Still -- in an actual crisis -- what I'd probably do is run the refrigerators off of our natural gas-powered Honda 3 kW generator and use the cart for things like the washing machine and gas dryer. Anyway -- what you want is absolutely do-able and I've got the system to prove it. You cannot expect, however, to run a full size refrigerator for an extended period of time on a small system like this.

If you happen to be in the Tucson area you're more than welcome to come by and look at the system and see how it was designed and constructed first-hand.

 

[rjmetals]

RJ - I'm also in Arizona and recently built a solar power "cart" for emergency use in the house. The finished system has two Battleborn 12v LifePo4 batteries in parallel, and uses a Victron 100/30 charge controller. I use three 195W panels wired in series and mounted them up on top of the ramada covering our back porch, facing due south. The inverter is a 2 kW pure sine wave, and can also charge the batteries if plugged into grid power. Everything is built into an audio-visual cart on wheels. I've tested the system on just about everything in the house, including our full-size refrigerators, and it runs most anything with ease. It will even run a portable room air conditioner for about two hours. The system also includes a Victron battery monitor, which allows me to see real-time how much juice is flowing when the cart is in use. When powering a modern refrigerator, the current draw varies quite a bit as the appliance moves through various cycles -- I ran our full-size refrigerator in the kitchen on the cart for a few hours one day just to see how it went, and it appeared that I could get about 5 or 6 hours out of the cart before depleting the batteries. Honestly, our vacuum cleaner pulls more power than the fridge. Still -- in an actual crisis -- what I'd probably do is run the refrigerators off of our natural gas-powered Honda 3 kW generator and use the cart for things like the washing machine and gas dryer. Anyway -- what you want is absolutely do-able and I've got the system to prove it. You cannot expect, however, to run a full size refrigerator for an extended period of time on a small system like this.

If you happen to be in the Tucson area you're more than welcome to come by and look at the system and see how it was designed and constructed first-hand.

AZRoadrunner: Any pictures you'd care to share...I also have a big audio/visual cart that I hadn't even considered for the project. Thanks!

 

[AZRoadrunner]

Sure! Here you go. I also included the system diagram. The only thing different is that I added a third panel. The wiring from the panels passes through the exterior wall and terminates in the dining room, where I put a disconnect switch on the wall. It's the "gas-n-go" spot for the cart. A hint to save you a surprise: add a fifth wheel on the bottom of the cart, near the center. There's a lot of weight with those batteries in there. Ace Hardware has a nice selection of heavy-duty caster wheels.

 

[HOU_Castle]

Hi everyone,
Lets start out by saying I'm a solar dummy. Looking to build an small emergency system to run home Samsung refrigerator/freezer (AC115V/60Hz 5.3A) in sunny Arizona when grid goes down. Thinking of 3000w pure sine wave inverter with 40A controller, 2x 12V batteries. Will this work in 12v or do I need 24v system? Do I need more batteries to make this work? What PV panels are needed? Thanks for any suggestions you can offer. Never built a system before. Sorry, don't know much. RJ

Recently, I ran my 6Amp-120V Maytag full size refridge French door type with 24V, 200Ah LifePo4 battery with inverter 4000/8000W Giandel. It lasted 49 hours without recharging the battery. The battery had about 10% juice left (about 20Ah). You need to plan for day without full sun or cloudy. When the compressor ran, it took about 600W, and fan ran about 150W. Inverter consumption without load is about 26W (1A) from battery.
I have 2 -320W panels to charge the 24V-200Ah battery via Victron MPPT 100/30. It took about 9-10 hours to fully charged the battery.

 

[Glots222]

How much is it using on startup and running?

Is there a meter that actually shows the ‘start up” watts and/or amps?
Was just trying that but mine (kill a watt style) takes a couple seconds to read after starting something.
Would really like to be able to measure start up.

 

[AZRoadrunner]

Is there a meter that actually shows the ‘start up” watts and/or amps?
Was just trying that but mine (kill a watt style) takes a couple seconds to read after starting something.
Would really like to be able to measure start up.

To measure start-up accurately, the best way is probably to use an ammeter. One of the clamp-around meters should do the trick.

 

[Glots222]

To measure start-up accurately, the best way is probably to use an ammeter. One of the clamp-around meters should do the trick.

Will this work?

https://www.amazon.com/KAIWEETS-Tem...1&keywords=Clamp+meter&qid=1622060245&sr=8-19

 

[beetlefan]

Will this work?

https://www.amazon.com/KAIWEETS-Tem...1&keywords=Clamp+meter&qid=1622060245&sr=8-19

it is right one, plus for easy test setup, you might need this one too, copied from DavidPoz YT video

Triplett AC Line Splitter and GFCI Outlet/Receptacle Tester with 5 Visual Indicators (ET200): Amazon.com: Industrial & Scientific

Triplett AC Line Splitter and GFCI Outlet/Receptacle Tester with 5 Visual Indicators (ET200): Amazon.com: Industrial & Scientific

www.amazon.com

 

[Ed Tech Sensei]

My fridge label was pretty meaningless in calculating the load. A watt meter will help you figure out how much power it uses to startup and run.

Same here. Label said 115v at 3 amps. 345 watts but I had no idea what that meant. I plugged the fridge into a Kill-a-Watt for seven days with the electronic control panel on. Ice-maker and cold-water on. The average was 55w per hour. I still didn't know the start-up load. I plugged the fridge and Kill-a-Watt into a Jackery 500. 500w PSW inverter, 514Wh battery.

Just shy of 9 hours the Jackery showed 9% so I guess the average really was about 55w and the start-up was under 500w. Maybe the 345 watts is the start-up.

My solar system is 12V. I have 360 watts of BougeRV solar. 3 kw battery bank. 1200w Giandel PSW inverter. Renogy 40 amp MPPT controller. I placed a load that varies from 80-100 watts on the inverter. I've been running it for 4 days. The low battery charge is 12.7V and the high 13.8V. We've had intermittent sun. Highest charge rate is 250w from solar between 10:30 am and 4:00 pm. Looks like I could run my fridge on this system indefinitely as long as there is enough sun. Need to get more solar.