Home whole house generator

Home whole house generator

Can a whole house generator charge the car?

Patrick | July 19, 2018


CharleyBC | July 19, 2018

How big is the generator, and what’s your charging configuration?

Gregg Ray | July 19, 2018

Yes, so can a solar system.

jwat14 | July 19, 2018

I have a 22KW standby generator, and I have noticed the extra electrical outlets, but I just presumed that they were 110 like the other household outlets. I will take a look when I go outside.

Daryl | July 19, 2018

Pretty inefficient! If you're going to burn gas might as well have an ICE car.

But if you're just asking in case of a long term power outage, then yes.

Treetoe | July 19, 2018

Ours is a back up generator. I am almost entirely dependent on home charging. 11Kw home generator

hyoyeaaa778822 | April 4, 2020

Yes of course.

bjrosen | April 4, 2020

Whole house generators are for emergency situations, they aren't a substitute for grid power so the inefficiency isn't important, reliability is what matters. They cost a lot less than a solar system, especially a solar system with enough battery backup to get you through the night. After enduring a winter where I had two outages that each lasted almost a week I got a Kohler 20KW system. Kohler's are more reliable then Generac's and they have a longer warranty, they are also quieter. The system cost me $12K installed. It cuts over automatically, they only way I know that it's cut over is that the UPSs on my computers beep for a second. I have two propane tanks which will give me about a week of power, that's enough because I've never had an outage go longer than that and of course you can have them refilled. The power is clean so there is no problem charging the car.

As a side note, you want backup for exactly the situations where solar isn't going to work. My power outages are caused by ice storms, they don't happen in the summer. Under the best of circumstances the days are short during the winter, add a layer of snow and ice on the solar cells and you aren't going to get a lot of power from them. | April 4, 2020

Out here in California, battery backup is a great way to go. Most outages are in the summer when you have the maximum sun to charge the batteries - which allows you to go indefinitely and still have the power to charge your EV. Agreed, it is a more costly solution than a gas generator, but I expect it is more reliable and you don't have to deal with storing any gas/diesel/propane or the noise of a generator.

plugzin | April 4, 2020

Pay special attention to electrically isolating from the grid when you operate a generator powering any of your home circuits. Do not allow backfeed to occur; injury or fatality may result. The alternative is to use extension cords leading into the structure to power specific loads or appliances, separate from your home wiring.

DO NOT CONECT A GENERATOR TO AN OUTLET IN YOUR HOME! And remember to operate fuel burning generators well outside the structure, and any openings into it.

SamO | April 4, 2020

You can buy 7kW solar + a powerwall for $12,000. If you spend more, you make more.

If you are a low power user, the above works great.

If you are a large power user, offset more of your power use with solar and battery. Some jurisdictions allow you to make a little $.

Tesla will be in that business of aggregating powerwall and solar users into a utility #soon enough.

andy.connor.e | April 4, 2020

1 Powerwall installation for me was going to cost $11k. That does include the inverter and all equipment plus installation cost. Maybe you could buy the solar and the powerwall and have it delivered to your driveway for that cost.

cussenjim | April 4, 2020

My primary charging for car is solar. All DIY, with 21 kw leaf battery pack and 5200 watts of solar.. Funny thing, on Galveston Island when Hurricane Ike hit in 2008, The power companies shut down electricity, then an hour later the gas companies shut down shut down all natural gas. All those standby natural gas generators became nice lawn ornaments.

coleAK | April 4, 2020

I have a 7kw hybrid on/off grid solar with a AGM battery back up and a generator as back up to solar for the 3 months it’s mostly dark up in AK. I installed most of it myself and had a electrician “tie it in”. As for winter if you get sun solar is more efficient in the cold. I clear the snow off my panels but installed them in a way that makes it easier.

Uncle Paul | April 4, 2020

First check to see if your generator is supplying 120v or 240v. No need to plug directly into the generator. Should be able to just plug into supplied home sockets.

If your generator runs your house air conditioning, it probably puts out 240v.Imagine you probably will not want to charge car and run AC at the same time.

Gotta be careful to not overload your generator.

Uncle Paul | April 4, 2020

First check to see if your generator is supplying 120v or 240v. No need to plug directly into the generator. Should be able to just plug into supplied home sockets.

If your generator runs your house air conditioning, it probably puts out 240v.Imagine you probably will not want to charge car and run AC at the same time.

Gotta be careful to not overload your generator.

cussenjim | April 5, 2020

Pretty easy to set your charging amperage. I run fridges and freezers on 120 volts off my inverter. I set my cars max charging rate at 8 amps at 240 volts. That way car charges as about 2000 watts or 8 miles an hour and rest of inverter output for 120 volt loads. Inverter runs off solar and batteries. You can use the same setup for your standby generator.

jamaica8484 | April 5, 2020

Not all generators can charge Tesla. Tesla requires clean and stable 60Hz power with low distortion. Many generators do not provide clean and stable 60Hz sine wave power that Tesla requires. Inverter generators generally work very well for charging Tesla and ones that can run on propane or natural gas are even better for long charging sessions with much less pollution. As for Powerwall/home battery, they work but definitely not justifiable on pure financial terms for backup power especially in regions with good NEM rates. However, depending on how you value eco friendliness, convenience and other non-financial factors it may be worthwhile. In any case, generator is still required for reliable on-demand backup power even if you have home battery especially if you have critical backup power needs (e.g. medical equipment like CPAP machine, stair lifts, etc.) as solar is not a reliable on-demand energy source that do not work well when there is clouds, rain, smoke, etc.

cussenjim | April 5, 2020

I guess it depends where you live, my rate from 1000 to 2000 kwh a month is about 10 cents a kwh, powerwall pay back would be 30 years. My home made system is about 5 years, just using it to charge my car as opposed to fueling my ICE cars.
I am down south so outages are usually fairly long after hurricanes. Sun is usually there after the storm, but have a 2000 watt generator that will recharge my batteries just in case. Did not have my solar system during Hurricane IKE in O8, but sun was out after the hurricane passed, so would have not needed the gen.
BTW. Just as an experiment, tried charging my car at 12 amps 120 volts with my cheap Harbor Freight generator, no problem. It was an inverter type though.

haha-yes | April 6, 2020

my experience; I recently had a wall charger installed in the garage by a tesla approved electrical contractor. I have 300 amp service with a 20k generac home standby generator. I could not utilize the generator since tesla does not approve of it for charging and had to pay extra for a load shedding device.

jamaica8484 | April 6, 2020

Perhaps your generator does not provide the clean power required. Tesla itself has used generators (assuming they provide the required clean power) for charging.

cussenjim | April 6, 2020

In haha's case, think Tesla believes correctly, that the 20 kw generator cannot supply the 300 amps his grid power provides. Thus they suggest a load shedding arrangement that will shed high amp loads when his Tesla is charging. Many motorhomes with smaller generators have the same load shedding device. Actually a good idea, would not want your ac, stove, water heater, etc and Tesla charging to be on at the same time and overload the generator, this may lower the charging voltage which could damage the onboard Tesla charger. All home s/b generators have regulated cycles and voltage, so quite safe for your Tesla, if they are not overloaded.