power a home refrigerator with a Tacoma and huge inverter?

[rexwang]

so i have this question, can i power a home refrigerator (722 KWh/Year) off a large inverter that is hardwired to the truck battery. Obviously the truck would be running.

I'm considering this in place of purchasing a generator.

i currently have a standard lead/acid battery in my 2.4L tacoma (96 single cab base 5lug) . The battery wouldnt be able to carry the load, but what about the truck/alternator?

thoughts please?

if needed, i can swap the vehicle for a 2005 dub cab tundra with the upgraded tow package which includes the hi output alternator (and hitch and trans cooler).

 

[lostinbsd]

Anything is possible really, but it is more a matter of practicability. With enough amperage being available from your alternator (at idle) you can easily run an inverter that can run a fridge. You really have to pay attention to duty cycle and inrush capability of the inverter though. Also how much fuel you plan on using. Realistically its far more efficient to have a small Honda/Yamaha or good inverted based generator for the amount of run time you are probably going to be looking for. Its a lot of wear and tear on your truck to just leave it running to power a fridge, but this is just my opinion.

 

[forty2]

Depends on the Amp draw of the fridge. Using just predicted kWh you also need a duty cycle to even start to get napkin numbers. Voltage multiplied by Amperage will give you the draw. From there you will know what size inverter you need (give yourself plenty of headroom here). From there you can figure out what the truck is capable of supplying. Using the lower end automotive voltage number of 12.6V nominal (alternators usually output 1-2V more) and say a 100A alternator that gives you 1260W. I don't know what kind of losses to expect from an inverter, but there is definitely a fair amount lost in heat, but this should get you a start. Most importantly you need the max amp rating of that fridge because everything spikes when the compressor kicks on and that's the draw you need to plan for.

 

[AaronK]

My old fridge is only a 3 amp draw. It will spike of course when the compressor kicks on. Seems doable.

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[M35A2]

Your truck is (ballpark) going to consume a gallon of fuel per hour idling. That's a lot of fuel burned for a small electrical load. How much is the inverter going to cost? How often will you need to run your refrigerator, and for how long each time? You will be better off buying a small genset.

Kwhr/year is meaningless. You need to know how much power the refrigerator draws per unit time. And also allow for the current inrush each time the compressor cycles.

You will also need a hefty extension cord since you probably do not park your truck in the kitchen. More losses if the cord is puny.

 

[rexwang]

this is a similar fridge to the one i have.
http://www.samsung.com/us/appliances/refrigerators/RF28HMELBSR/AA

the i live in an area thats densely populated in orange county, ca. We dont get power outages too often so its not critical that i burn gas for the few times ill use it as its intended.

looks like as of right now the weak link in my idea is the alternator. i would need a high output (~200amp) unit for this plan to pan out.

Unless there are some other ideas to handle the surge load. 1F capacitor?

 

[v_man]

Having grown up in the OC , I can't remember the power going out for more than a few hours, maybe half a day max. But if I understand this you're making a plan to use your Toyota to power your fridge on the off chance the power goes out for a few hours ?

 

[rexwang]

basically. in a nut shell yes. but im considering a power outage for a full day or more.

i know it sounds crazy but heres the deal.

we are new parents and our kitchen freezer goes down to -6°F. which is awesome and also means that we keep our "liquid gold" in there. i cant risk having that defrost. not so crazy anymore...

 

[AaronK]

Your truck is (ballpark) going to consume a gallon of fuel per hour idling. That's a lot of fuel burned for a small electrical load. How much is the inverter going to cost? How often will you need to run your refrigerator, and for how long each time? You will be better off buying a small genset.

Kwhr/year is meaningless. You need to know how much power the refrigerator draws per unit time. And also allow for the current inrush each time the compressor cycles.

You will also need a hefty extension cord since you probably do not park your truck in the kitchen. More losses if the cord is puny.

Seems high for most vehicles. My 2UZ Tundra uses .48 gallons per hour at idle

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[rexwang]

even if it was a gal per hour, that would mean that the tacoma would have an easy 10 hrs of runtime and the tundra would have 20 hours.

im good with that. but my alternator amperage seems to be the weak link.

assuming the fridge is 722W. then a safe surge wattage is double. so that would be ~1500w. 1500w/12v = 125 amps.
thats a lot more amperage than i have.

 

[Buddha.]

Seems high for most vehicles. My 2UZ Tundra uses .48 gallons per hour at idle

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My 4.3L is about the same, that's what my scanguage says at least. I'd probably try to idle it up a bit if I was trying to run a fridge off it.

 

[rexwang]

you can idle up a little bit but the voltage regulator will cap it off at a certain point. perhaps 1100rpm?

but if the battery shows a need to charge, ive seen my tundra hit 13.7 volts for quite some time then drop back down to normal voltage ~13ish.

 

[plh]

You should put a Kill-A-Watt on that 'fridge because I doubt it would be pulling 722 watts continuous. Its probably 3 to 5 amps while the compressor is running, and maybe the start-up surge is 6 (722). Plus, the compressor is OFF for a lot of the time so during the OFF time maybe 1 or less draw. I would think that a 100 amp alternator and a normal sized car battery (60 to 80 amp hour range) should be able to handle your 1 day situation. 750 watt inverter with a surge headroom of at least 60%.

so that would be ~1500w. 1500w/12v = 125 amps. thats a lot more amperage than i have.

No its not. The inverter draws the power from your battery and this surge would only be momentary. Your battery can momentarily supply a LOT more than 125 amps. Your alternator continuously replenishes the battery. Inverters draw power from your battery as needed also they are not a continuous load. So when a 750 watt inverter is actually putting out 750 watts (~6 amps output @ 120V) its going to draw about 75 amps @ 12V from your battery (there is an efficiency loss), but at a 1 amp @ 120V load it will only draw about 13 amps from your battery. FWIW These are all very general ballpark numbers.

 

[raintoy]

For some more fun research check out http://battery1234.com/

Podcast part way down talks about powering your household items with your car. Also has shows on building a home battery bank and choosing a generator.

 

[1Louder]

Get a generator for your house..... this sounds like George Costanza taking the Frogger machine and trying to keep it running to keep his high score alive. Or get a ARB fridge or similar. Then if you need to leave the area you can still have a freezer.....