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Using a 2008 Toyota Prius as a generator for my house

I love my Prius and I hope I can love it more. We in NorCal have seen so many power outages replaced by extremely loud and environmentally toxic generators. I’m hoping that my Prius can be used as a generator for my house. I just need enough power for a refrigerator. I read about an “inverter” That hooks up to a car battery so the car becomes a generator. It converts the 12 volt battery to 110-volt electricity. Is this something that would work with my environmentally friendly and very quiet Prius? Is it worth trying? Could an auto repair shop do this?

If you have a lot of power outages, you’re better off installing one of these.


Start with solar installers, or an electrician that works with solar companies… They’d have knowledge of inverters, and could possibly figure out if there’s equipment that would serve your situation. I have a hunch there’s a way to do this, as long as you are willing to just power the refrigerator directly from the car battery (with an extension cord), keeping it disconnected from the house wiring. But actually connecting to the car could be complicated.

I also live in northern CA so am well acquainted with the “safety” power outages, and I agree about the relentless noise of generators.

You might also be intrigued by the concept of “vehicle to grid” or “V2G” for short. The idea is to use large numbers of electric vehicles as a mega-battery to power the grid in times of brief heavy power demand, such as extreme summer heat. That’s far beyond your situation, but could be interesting to investigate, especially with PG&E power shutoffs a reality for short periods in late fall.

“Is this something that would work with my environmentally friendly and very quiet Prius?”

No. Unfortunately, you are looking for an environmentally friendly “free lunch”.

  1. I think your Prius’ 12-volt battery is charged from the gasoline engine (at least when the car is sitting there running your refrigerator). You would have to keep the car running to power the refrigerator. If the gasoline engine is not running, the refrigerator would drain the 12-volt battery in a very short time (see #2 and #3). (MAYBE the drive battery could provide some power for a little while. I don’t know if it ties into the 12-v system.)

  2. I estimate that your refrigerator needs about 5 amperes (that is, more than 2, and less than 10) to run; maybe more for starting surges. (I wish I had better data. I looked at the manual for my 18-year old (yikes!) refrigerator. It does not specify the electrical power or current. It just says to use a 15 or 20-amp branch circuit, preferably with no other load.) 5 amperes at 110-volts is about 550 watts (ignoring the “power factor” for non-resistive load).

  3. To get 550 watts from a 12-volt battery with inverter, you would need 45.6 amperes (i.e., 550 divided by 12), and that ignores the less-than-100% efficiency of the energy conversion. I doubt that your Prius’ 12-volt charging system can deliver that much. (I also doubt that an available inverter could handle that much power.)

If you deem an “extremely loud and environmentally toxic” emergency/back-up home generator unacceptable, look into a solar powered storage-battery system. Or get a freezer and keep a bunch of gallon bottles of frozen water handy to chill the refrigerator when the power goes out.

Good luck.

OK, so this is not recommended, but my electricisan bud was stupified, but I guess it will work he said. Now there is a lot of dangers to house and home and lineman if you do not understand electricity. So don’t sue me as I do not recommend this to anyone.
Your car voltage will suck.
I have a 3500 watt generator I backwire via romex cable to an outlet, polarity observed, that is a hard part, so power goes out, I turn off the main breaker so I do not electrocute a lineman, plug it into an outdoor gfi outlet, now there are 2 legs on a typical electric panel, I get heat tv and lights, but I would recommend a natural gas generator with a certified break box. Do not do as I do.

The Prius is definitely not limited to 12 volts.

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“The Prius is definitely not limited to 12 volts.”

Of course not, and I did mention maybe using the HV drive battery. However, the OP asked about using a 12-V inverter, so that’s what I addressed.

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I also live in NorCal and own a Prius. We got a portable 3500 watt generator at Costco. Our house is all electric, including the well. With a heavy duty extension cord we run the refrigerator for a while and the separate freezer for a while. We use a small portable battery backup for our wireless (no cable here) internet connection and router. We cook on a small propane campstove. After the 2017 firestorm, we had a 3500 gallon water holding tank installed, which is a few feet above house level. After the pressure tank is depleted, there’s enough gravity feed to fill the toilets, wash dishes, etc. Not enough for a shower.

I saw an inverter on Homedepot’s website. It needs to be connected directly to a 12V battery. The 12V cigarette-lighter-type connection won’t supply enough power. If you tried connecting it to you Prius’s 12V system, you would need to be very careful not to zap one of the car’s computers. That could end up costing you a lot more than installing a switch-over backup generator suggested by one of the other posters here.

A lot depends on how much you want to “rough it” when the power goes out. We had no power for 2 weeks after the 2017 firestorm. The didn’t force us to leave, but if we left, we couldn’t get back home. So we “camped in” for the two weeks cooking on our camp stove, switching the portable generator back and forth between refrigerator and freezer, and carrying water in buckets for our neighbor’s holding tank (hadn’t installed ours yet). Friends were able to hand us containers of gasoline across the “no entry” barrier. The barrier was primarily to keep looters out of our area.

The 12v battery in a Prius offers no more potential electric current than the battery in any car which isn’t much and certainly not enough to operate a refrigerator through an inverter. And the array of batteries that powers the hybrid drive has no way to convert its 200 to 300 volt direct current over to 110 volt 60 hertz alternating current for household use.

Maybe if you get bored surf the net for a good course on basic principles of electricity. There’s just a great deal to consider that I understand and I’m just a tired old mechanic .

I had a colleague who had a vacation home in the southwestern part of the U S. which was off the grid. He bought a Servel gas refrigerator from one of my friends and had it converted to propane. Now your chances of finding a Servel gas refrigerator may be slim since the company closed in 1957. However, I think there are propane powered refrigerators that are made for RVs. You might look into this as a backup when the power goes off. You could transfer your food from the electric refrigerator to the gas refrigerator when the electrical power is off.


Living in stormy rural Maine, we replaced our noisy portable gasoline 5500w generator with a Kohler, running off propane tank(s). It was an investment in the house, and in our comfort and health. With the need for an upsizing of propane tank and addition of a second tank, the installation costs on those and on the generator about doubled the price of the generator. This is the safe, and legal way to do this, and recommended. Extension cords and gasoline refills get old fast (as well as dangerous) esp. as you get older!

If anyone thinks there electric or hybrid car would be ecofriendly used as a generator, consider this. The bulk of our electricity is still supplied by natural gas with coal in second place. The 2018 figures, the latest I could find had fossil fuels at over 63% and nuclear at almost 20%. Solar is only 1.5%. Wood is 1%. Wood generates 2/3 as much electricity to our electric grid as solar. That is an awful lot of feel good publicity for such a small effect.

To put it another way, the electricity to power you electric car [s 6 and one half times more likely to come from coal as from solar and more than 40 times more likely to come from natural gas. Add to that the transmission losses of transmitting electricity for long distances I think you might to do just as well environmentally to just operate your Prius with the gas engine and not plug it in. Some states are now imposing taxes or fees on electric cars to make up for lost gasoline tax money. True, some utilities are letting you buy solar produced electricity for a little higher price. This is a cruel hoax on people who are trying to help the environment because then the electric company just sells the rest of us less solar.

This reminds me when a friend of mine who was a teacher was loud in support of NY States propaganda selling the bill that enabled the NY lottery. The state promised all the lottery profits would be used for education. What the teachers didn’t realize was the state spending on education dwarfed any potential lottery profit so it did not increase spending foe education, they just took less money out of the general fund.

I use a 3500 watt inverter with my wife’s Hyundai Elantra. That pulls 250 amps when I keep the load at 3000 watts and provides me 27 smps to run the fridge and furnace and some lights. Since I’m pulling more out of the battery then I’m putting back, I don’t do this for too long.

Yeah sorry I guess I should have read more carefully.
Seeing a conversation about a Prius as a home generator I just quickly assumed it would be about more than the 12 volt battery.

Well that’s interesting. Power outages are not a problem here in southern Minnesota but I’ve had maybe two 3-4 hour outages in the last five years. Still I have a 2000 watt generator for other uses and always figured I’d just run extension cords as necessary. But the idea of feeding the house through an outside outlet is something I never thought about. Of course shutting the main breaker off, and only one side of the breaker box would be powered up. Something to think about if we have another tornado.

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The danger comes from folks not tripping the main breaker. This can electrocute line workers.


How long can you run it before it drains your battery or fries your alternator. Doesn’t sound like it would do overnight.

I have a 5500 was gasoline generator, $ 500 or so. I bought it 11 years ago after we had an October surprise that took down trees and tree limbs. The tree limbs in my yard, still with green leaves were piled in my yard as high as my head. Power was out 5 days. I have liver here 51 years and the power has gone out for more than 15 minutes only once so I have never needed my generator. Every other year I put a small amount of gas in it and run it dry. While it is running, I plug my electric chain saw in and make sure it will still generate. If I needed it often I would convert it to natural gas.

My alternator puts out 200 amps, and at full load the inverter draws 250, so the deficit would be 50 amps at full load, clearly not sustainable. Typically I manage the load to keep the draw under 200 amps, which an engineer at Denso assured me can be supplied continuously by the alternator.

Normal home service is a 200 amp panel to supply everything. Normal 15 amp circuits are about 2000 watts. A little gas generator would supply one circuit or about 2000 watts and a bigger portable generator might do two to four circuits. Are we talking a 12 volt car alternator trying to invert to 120v alternating current? Just a little confused by all this and why you’d want to use your car anyway instead of what has become a standard way to power up in emergencies.

Speaking of DC versus AC, anyone see Current Wars yet on Edison DC fighting Tesla AC back in the good old days?