Solar/battery powered portable freezer or fridge?

Question

Well, last week we got hit by cat 5 hurricane Maria. So I'm thinking, one of the things I miss the most right now is ice.

Considering the amount of sunlight that we have, does a battery-powered portable freezer that can be charged by sunlight exist?

This is what I'm thinking: I buy a portable freezer/fridge that somehow runs with a battery. This battery would somehow be charged by a device/panel that charges the battery with the sun. The freezer would be running about 8 hours/day. After 8 hours, I simply switch the battery with another (recently charged) battery.

Considering the advances made with solar technology, does something like this exist?

I've been thinking about a regular gas generator, but considering the amount of sheer sunlight that we have, there has to be something else besides gasoline/diesel. Also, gasoline is quite scarce.

Thanks.

Answer 1

Yes, there are plenty available - just look for those designed for use in a Motorhome/Caravan. These are designed to run off of 12v, so you can connect them to a deep-cycle leisure battery and charge that using solar panels.

Many are also "3-way", in that they can run off 12v, 240v mains or gas (lpg/cooking gas, not petrol/gasoline).

To set up such a system, you'll need, in addition to the fridge, a suitable battery, a solar panel, a charge controller (the bit that enables the solar panels to charge the battery correctly without overcharging it), and the necessary wiring.

The battery needs to be big enough to run the fridge overnight (so kWh of the fridge * number of hours without sun + margin), and the solar panel big enough to fully charge the battery while also running the fridge (kW / number of hours of sun + kWh of the fridge). Of course, if your existing fridge is efficient enough, you could even get a charge controller with a built-in mains inverter, and plug your normal fridge into that - but fridges use a lot of power, especially at startup, so you'd need a hefty inverter and battery...

You should be able to get all the bits from any decent RV/Caravan/Motorhome supplier, or, as you're in a coastal region, you should also be able to get them from a chandlers (boat supplier) - particularly if you've got one nearby that deals a lot with leisure yachts.

Here's an example of a solar charging kit, containing most of the bits you'll need (and with a list of what else is required): uk.rs-online.com/web/p/photovoltaic-solar-panels/7067924

Answer 2

Yes this is possible. It is not a good use of your resources. This makes sense if you are going off grid, but for something that is only going to be used when your power goes out, it makes more sense to buy a small generator.

If you want to run your fridge/freezer you need several hundred watts. If you want to run it at night you need a battery bank, and a bunch of controller circuitry to do it right.

• It has more uses: Take it camping. Use it to power your tools on the back 40 (where mine is right now)

• It's a single item, not a combination of panel, controller, batteries, inverter.

• You can sell it, loan it to your father-in-law.

A cheap generator is a few hundred dollars. They aren't very efficient, but you will be able to run your fridge for a few hours a day to keep it cold, keep the sump pump running, etc. In power outages here we find it takes about 3-4 gallons a day to keep the freezer, the fridge and the sump pump going. This leaves it idling most of the time. Since I have two mowers, a chainsaw, an auger, soil mixer, farm pickup, and two tractors, I have 4 each of gas and diesel jerries that cycle several times a year.

The next step up are ones that are really quiet. These are the ones that people with motor homes buy. 1 to 2 kW and you hardly know they are there. About double the price. They are also more efficient, slowing down under light load.

After that, you have a raft of options between diesel, natural gas, propane and gasoline, electric start, whole house systems, automatic transfer to the generator when the power goes out.

Before you buy, rent one. Verify that it will run all the things that you need. Set up conditions that could shoot you in the foot: E.g. Compressors draw a lot of current starting. What happens if your freezer and your fridge start at the same moment? Might just slow the generator down. Might stall it, or trip the breaker on the genset.

Store it empty. Have a couple of gas jerries. When you get a hurricane warning, fill the jerries. Use them up in the lawnmower later.

Gas has a limited shelf life. Gas with ethanol only a month or so at warm temperatures. If you want to store full jerries, then get no-ethanol gas (premium usually) and add a cap full of gas-saver to it. Store them out of the sun.

If you need a generator to be ready, fill it up with your preserved gas, start it, get it going well, then shut off the valve on the fuel line until it quits. This leaves little or no gas in the carburetor to dry and gum things up.

Answer 3

The only thing I can think of is a Coleman cooler box. Runs on 12v. Made to run on a vehicle battery. Or a kooltron. You find these in truckstops. They do not freeze but get cold inside.

Answer 4

I learned about this method from Stephen Harris of solar 1234.com. A small tabletop ice-maker may be the way to go to continuously make about 10lb of ice a day while the sun is out if aolar, or 25 lb of ice if running 24/7 via batteries or generator or car powered inverter. But i think 10 lb a day would be Enough to to keep a single cooler chilled The table top units draw approx 130 watts so it is only a fraction if what even a small generator will be producing. So you can run a few off a generator if you have the $ and energy budget. . a regular full size frig pulls about 200 watts. Also The table top ice makers are sort of portable by car, and can be run from smaller inverters of 200 to 300 watts running from your car or solar system. These are more efficient for this amount of wattage load than a big inverter of say 1500 watts. The car inverter method requires you to allocate fuel and time to babysit the car and keep turning it on periodically when the battery gets down to the low 12v range (a 12 volt battery is closer to 13v when charged fully and is well drained by the time it gets to 12volts so dont let it drop or stay long past 11.3v. If you wont be using the car and fuel to power the inverter you cam look into a solar array with a battery. I guess a 300 to 400 watt array would be sufficient on a sunny day. The reason the table top unit is better than a conventional freezer is it is more specialized and efficient than a regular freezer in that the h2o being cooled is in direct contact with the cold metal / the evaporator. The ice cube making tray essentially has the evaporator built right into it so the metal pulls heat from the water faster than cold air would in a conventional freezer. So it doesn't have to run as long. overall in theory would use less power. It eliminates the cooling and circulation of air. ice-maker is more efficient than conventional freezer at making ice more directly from the cold metal of the evaporator unit rather than calling air which in turn caused the ice. Making the most of your 130 watts per hour. Also check out Sundazer brand of super efficient 100watt chest freezers. Chest style is better than a front door style that lets the cool air run out when the door opens. And steer away from an auto defrost freezer if running on limited power. Defrost cycles increases power consumption. Hope this is helpful. I baby sat my frig during irma. But should have transferred items to a chest freezer beforehand. Listen to stephen harris podcast on dealing with power outages at Solar1224.com