Vehicle to Home (Ford Figured it Out)

[HaulingAss]

I'm sure the people of Texas would have liked there Tesla to power part of there home in the emergency this spring! This is a no brainer!!

A lot of Texas homes have electric heat with resistance wall fan heaters in the bathrooms. In a power outage like Texas experienced recently, you couldn't even heat a moderately sized home for one day with a 100 Kwh worth of battery power (110 Kwh minus 10% for conversion inefficiency).

One of the misleading facets of Ford's presentation was the way they seemed to assume your truck battery is going to be 100% charged when the power goes out. That's not realistic as an EV is almost never kept at 100% state of charge and this kind of power outage is not announced in advance. If you drive your truck home from work and find a cold, dark house, chances are your battery is between 30 and 60% state of charge, not a whole lot to warm it back up if you have electrical resistance heat which is fairly common throughout Texas. Since 2010, 62% of homes built in Texas use electric heating.

And do you really want to draw the battery in your truck down to zero? Then it becomes a big, worthless brick.

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[HaulingAss]

Exactly. Ford touts home backup power, frunk, and paint colors because they can not compete with Cybertruck on truck features - price, range, payload, towing, vault, adjustable height air suspension, air compressor.

Don't forget the eleven (11) electrical outlets on the Lightning. Never mind that most people will be using heavy extension cords with splitters. Tesla has not announced the exact number of outlets but you can be confident they will not even be tempted to compete with Ford on such a useless metric. It was obviously done so Ford could say, "Dude, this truck doesn't stop at 10 electrical outlets, it goes all the way to 11!

 

[HaulingAss]

This isn't exactly rocket science.

Thank God for small miracles! Because this isn't an Elon Musk company we are talking about - it's Ford. And they have to design their end properly. So it's a good thing it ain't rocket science!

 

[Red61224]

A lot of Texas homes have electric heat with resistance wall fan heaters in the bathrooms. In a power outage like Texas experienced recently, you couldn't even heat a moderately sized home for one day with a 100 Kwh worth of battery power (110 Kwh minus 10% for conversion inefficiency).

One of the misleading facets of Ford's presentation was the way they seemed to assume your truck battery is going to be 100% charged when the power goes out. That's not realistic as an EV is almost never kept at 100% state of charge and this kind of power outage is not announced in advance. If you drive your truck home from work and find a cold, dark house, chances are your battery is between 30 and 60% state of charge, not a whole lot to warm it back up if you have electrical resistance heat which is fairly common throughout Texas. Since 2010, 62% of homes built in Texas use electric heating.

And do you really want to draw the battery in your truck down to zero? Then it becomes a big, worthless brick.

Personally, this is why I heat my home with a wood stove, by choice, and I have a propane-powered backup generator (500-gallon in-ground tank) power for week-long power outages during hurricane season, my propane supplier delivers and I don't have to queue up to get any fuel. Freezers, fridge, and heat pump-style water heater run off the gen set easily. And the best part I will be able to charge my EV off the generator like Alfred E. Newman.

 

[HaulingAss]

This system is supposed to be able to deliver 9.6 kW. That's quite a bit.

9.6 kW is not "quite a bit". My 2 bedroom ski cabin draws 28,800 kW as soon as I turn on a shower or the kitchen sink. And that's assuming I have no lights, stove, oven dishwasher, washing machine, dryer, microwave, iron, refrigerator/freezer or room heat on and the hot tub is hibernating. That's three times the Lightning's load limit just by opening a hot water tap.

The Lightning would be utterly useless backup power for my ski cabin, the load breaker would trip instantly unless I wanted to live with ice cold water of 41 degrees and turned off my spa, and range and didn't do any laundry and only used the microwave to cook with (or the wood stove) and the wood stove to for room heat.

 

[Crissa]

Your water heater uses 28kW? That's pretty amazing. That's like five commercial electric stoves. An electric forge doesn't use that much power.

A 100kWh battery will run a space heater over fifty hours straight.

And Tesla already has storm-tracking software in their Powerwall and Tesla apps. They tell it to charge to full and not discharge when a storm is predicted. Without your intervention.

I'm sure Ford can figure this out.

-Crissa

 

[HaulingAss]

Your water heater uses 28kW? That's pretty amazing. That's like five commercial electric stoves. An electric forge doesn't use that much power.

Actually closer to 29 kW, it takes three 240V 50 amp breakers so I would need to switch to a tank style water heater which is 5.5 kW but runs over 5 times as long for the same amount of hot water. Even then, the Ford would struggle or blow the overload protector if anyone turned on another high draw appliance when the water heater was heating.

A 100kWh battery will run a space heater over fifty hours straight.

That's true, but you have to look at how few Btu's only one space heater produces. In the winter it's not enough to heat the typical home in winter..

And Tesla already has storm-tracking software in their Powerwall and Tesla apps. They tell it to charge to full and not discharge when a storm is predicted. Without your intervention.

I'm sure Ford can figure this out.

I'm confident Ford would not charge the truck to 100% simply because stormy weather was forecast. A truck battery is not a stationary Powerwall battery and shouldn't be treated like one.

We will see how serious Ford is about this V2H software. My guess is they will not be offering a lot of support, at least not at a price that many people will be able to afford. It's a very niche use case to power an entire house with an EV although I'm sure Ford will use it to help make the $90K+ truck seem like a better value. I think people will use it to run routers and modems, charge laptops, phones and tablets, keep a few lights on and the refer running and make coffee or tea.

Houses that rely on gas heat and gas hot water and have gas clothes dryers and gas ranges will find it more useful (although probably not all that cost-effective considering the extra equipment and labor required to make it all happen).

 

[Crissa]

That's enough power to melt a significant amount of steel.

If you can't get by without using more power than my entire house uses in a day to take a shower, something it wrong here, and it's not Ford's battery backup system.

-Crissa

 

[firsttruck]

That's enough power to melt a significant amount of steel.

If you can't get by without using more power than my entire house uses in a day to take a shower, something it wrong here, and it's not Ford's battery backup system.

-Crissa

Do you have gas water heater with tank?

Normal electric tank type water heater are slow to heat but keep the water for long periods of time in a heated tank. These are much lower wattage but run at that power level for very long time ( 45min - couple hours). The heater normally needs to start heating the cold water 45 minutes before you want to use it. During use the heater keeps heating and after your water use stops it might keep going for another 45 minutes to hours.

I think HaulingAss has a whole house high output instant tank-less electric water heater. The big ones can be 28KwH or higher. Very high wattage when operating but they only operate for the seconds, minutes that water is actually flowing. The second you close the water valve and water stops flowing the heater stops heating. No preheating except for any cold buffer because of distance of cold water & pipes between where the heater is and where hot water is being used. Depending on water use pattern this type of heater can be more economical in electricity usage. But it depends on the use pattern because there are cases where it goes up a lot. Especially if you do not have energy usage conscious occupants since the hot water never runs out some people use a lot more than they should.

I have a gas tank-less. I do not like the one I have because even though it is tank-less I have to wait 10 minutes to get hot water & run the water during that whole preheating time (wastes water). This is true even though gas flame burns firery hot.
There are two main problems with my installation.
1. The gas supply to the building is too small for the heater and so the heater can not make a big enough flame to be do truly instantaneous heating of the water to high temp.
2. The heater is a long way from the shower and the pipes in between are relatively cold so the cold pipes are absorbing the heat for the first minutes hot water is flowing through. Once the pipes warm up hot water finally comes out the shower head. I think tank type water heaters leak heat along the entire hot water line so the entire line usually does not get as cold between uses.

Here is link to Home Depot which lists several models. Looks to be fairly common capacity level. Most models are a little smaller like in the 18Kw range.

28Kw 5.3 gpm
Energy and cost savings of up to 34% in whole-home installations
Water heater requires 3 x 40 AMP double pole breakers
https://www.homedepot.com/b/Plumbin...tric-Water-Heaters/27000/N-5yc1vZc1tyZ1z18poe

36Kw 7 gpm
Energy and cost savings of up to 34% in whole-home installations
Water heater requires 4 x 40 AMP double pole breakers
https://www.homedepot.com/b/Plumbin...tric-Water-Heaters/36000/N-5yc1vZc1tyZ1z18plw

 

[ajdelange]

9.6 kW is not "quite a bit".

Yes, actually it is. I live in a pretty good sized house with 3 heat pumps (2 of which are equipped with electric E-heat), one A/C and a walk in refrigerator. I also charge a Tesla X. I have electric ovens and an electric clothes dryer. The picture below summarizes my demand over a full year. Note from it that my peak demand is 33 kW.

Note that 9.3 kW is exceeded only 6.9% of the time. That's spread over the year

My 2 bedroom ski cabin draws 28,800 kW as soon as I turn on a shower or the kitchen sink.

This implies that you have an electric water heater that draws 120A and produces 98 kBTU/h. You must have one of the "tankless" units (I see them up to 36 kW on Lowe's web page). If you have one of those (which requires 4 x 40A breakers!) then no, you would not be able to use a 9.6 kW as a backup source nor, in fact, any backup source (generator) of less than 30 kW capacity if you wanted hot water. Were I in your position wanting to protect myself from power outages I would go to one of the Navien or Rinnai tankless water heaters that run on propane/LNG (or install a 48 kW generator). They do use a little electricity but not much. They have units with two loops; one to heat the building and the other for the DHW. Very efficient too.

And that's assuming I have no lights, stove, oven dishwasher, washing machine, dryer, microwave, iron, refrigerator/freezer or room heat on and the hot tub is hibernating. That's three times the Lightning's load limit just by opening a hot water tap.

The Lightning would be utterly useless backup power for my ski cabin, the load breaker would trip instantly unless I wanted to live with ice cold water of 41 degrees and turned off my spa, and range and didn't do any laundry and only used the microwave to cook with (or the wood stove) and the wood stove to for room heat.

The art in backup system design is contained in the load shedding scheme. New regulations require that your backup source must be able to supply all loads connected to it. Your cabin would be pretty much ineligible for any backup system unless you installed automatic load shedding. You'd probably need a 48 kW generator (such as Kohler's Fortress in that size) with their Amplitude or Symphony load shedding modules installed. The way this works is that if you have something in the electric oven and are running the clothes dryer and hot tub and someone opens a tap total house load is going to go up to or over 80% of the generator's capacity. It senses this and opens a contactor feeding a lower priority load such as the oven or the clothes dryer. When the water heater stops drawing current the generator (actually its the ATS) senses this and reclosed the contactor to the shed load. What's interesting here is that as the tankless electric heaters require multiple breakers there is the possibility of shedding one or more of those if the generator comes on and demand requires it. You could then have hot water and perhaps the clothes dryer simultaneously if you realized that you would have to draw hot water slowly to have it at temperature. I do something like this at my cabin with the e-heat. It is in 3 stages (had to modify the heater to get it that way) and stages are shed if the generator is heavily loaded - never actually happened AFAIK but that's the design.

A smaller backup source, such as the Lightening, could be used as they most commonly are, in an installation that uses it to power a limited number of circuits such as a few lights, some outlets, the communications gear etc. Thus, in a power outage, you would have some lights, internet, be able to run a microwave, small space heater, electric blanket etc and watch videos but you wouldn't have hot water. This is where the Rinnai/Navien solution shines. A small backup source will run them for days (as long as the propane tank is full).

 

[ajdelange]

The more I think about it the more intrigued I am with these electric instant heaters. A 36 kW unit would draw 150 A which is more than I have ever used in a 4500 ft^2 house even in the dead of winter while charging the X. I like long hot showers so that load could be on for half an hour. Clearly one of these could not be installed in a house with 100 A or probably even 200A service. So I am curious as to what size service you have.

From the POV of required service capacity, wiring and backup challenges these do not seem like a very practical approach to hot water especially given the availability of the propane/LNG alternatives. But there certainly are lots of them offered so I guess they are popular.

 

[HaulingAss]

The more I think about it the more intrigued I am with these electric instant heaters. A 36 kW unit would draw 150 A which is more than I have ever used in a 4500 ft^2 house even in the dead of winter while charging the X. I like long hot showers so that load could be on for half an hour. Clearly one of these could not be installed in a house with 100 A or probably even 200A service. So I am curious as to what size service you have.

From the POV of required service capacity, wiring and backup challenges these do not seem like a very practical approach to hot water especially given the availability of the propane/LNG alternatives. But there certainly are lots of them offered so I guess they are popular.

There is no natural gas available within 20 miles and propane costs a lot more than electricity and requires a large propane tank and regular deliveries by an ICE truck. It is one of the least sustainable solutions.

My ski cabin has 200 amp service which has been pretty much standard residential service in the US for decades. It's more than enough for my all-electric ski cabin with electric everything including a 60 amp EV charging circuit and 50 amp hot tub circuit. The instant hot water is on three 240V 50 amp breakers. I did an experiment where I turned on everything I could think of (including charging my car and running the mini-split heat pump). Nothing tripped and the main panel connections never got more than warm.

Because the cabin is occupied only 30-40% of the time the on-demand water heater eliminates considerable standby losses. It was also the only solution that allowed mounting close to the kitchen sink/dishwasher which means I don't have to wait 30-45 seconds to get hot water which probably saves more than the elimination of standby losses.

A tank style heater is also problematic due to the incoming water temperature of 41 degrees F, year round. A small group of skiers can bring it to it's knees in record time and it will take hours to recover. The on-demand electric unit can run two low-flow showers simultaneously indefinitely but only because I installed a heat recovery drainpipe on the upstairs shower. Without that, only one shower would be possible at a time due to the icy incoming water temperature. The heat recovery drainpipe raises the incoming water from 41 to 65-70 degrees whenever it's in operation.

The Ford Lightning can power low powered devices for multiple days like Ford claimed but most houses have somewhat higher power demands and, depending upon the state of charge when the power is lost, even these lower power loads like lighting, small appliances, electronic devices and refrigeration could add up and become problematic during a multi-day outage if you don't want to end up with a completely flat truck battery. Higher loads like water heating, space heating/air conditioning and (of course) EV charging will need to eliminated or drastically reduced, even if the truck was at 80%-90% state of charge when the power was lost.

I mentioned EV charging because that is precisely why I don't like using V2H. Not only would you not want to charge an EV with it (counter-productive), it has the opposite effect, just what you don't want, a flat battery in your EV with no way to charge it. Depending upon the nature of the outage, you might not want to use it at all!

I suppose it might be useful if you had a fleet of $60K EV trucks to draw from and could reserve one or two for emergency transportation needs but that brings us full-circle. It's much more cost effective to just have 3-5 Powerwalls dedicated to home power backup and load balancing the grid. EV's are for transport, not backup residential power, at least not beyond low powered devices or very limited usage of higher-powered applications.

 

[madquadbiker]

There is no natural gas available within 20 miles and propane costs a lot more than electricity and requires a large propane tank and regular deliveries by an ICE truck. It is one of the least sustainable solutions.

My ski cabin has 200 amp service which has been pretty much standard residential service in the US for decades. It's more than enough for my all-electric ski cabin with electric everything including a 60 amp EV charging circuit and 50 amp hot tub circuit. The instant hot water is on three 240V 50 amp breakers. I did an experiment where I turned on everything I could think of (including charging my car and running the mini-split heat pump). Nothing tripped and the main panel connections never got more than warm.

Because the cabin is occupied only 30-40% of the time the on-demand water heater eliminates considerable standby losses. It was also the only solution that allowed mounting close to the kitchen sink/dishwasher which means I don't have to wait 30-45 seconds to get hot water which probably saves more than the elimination of standby losses.

A tank style heater is also problematic due to the incoming water temperature of 41 degrees F, year round. A small group of skiers can bring it to it's knees in record time and it will take hours to recover. The on-demand electric unit can run two low-flow showers simultaneously indefinitely but only because I installed a heat recovery drainpipe on the upstairs shower. Without that, only one shower would be possible at a time due to the icy incoming water temperature. The heat recovery drainpipe raises the incoming water from 41 to 65-70 degrees whenever it's in operation.

The Ford Lightning can power low powered devices for multiple days like Ford claimed but most houses have somewhat higher power demands and, depending upon the state of charge when the power is lost, even these lower power loads like lighting, small appliances, electronic devices and refrigeration could add up and become problematic during a multi-day outage if you don't want to end up with a completely flat truck battery. Higher loads like water heating, space heating/air conditioning and (of course) EV charging will need to eliminated or drastically reduced, even if the truck was at 80%-90% state of charge when the power was lost.

I mentioned EV charging because that is precisely why I don't like using V2H. Not only would you not want to charge an EV with it (counter-productive), it has the opposite effect, just what you don't want, a flat battery in your EV with no way to charge it. Depending upon the nature of the outage, you might not want to use it at all!

I suppose it might be useful if you had a fleet of $60K EV trucks to draw from and could reserve one or two for emergency transportation needs but that brings us full-circle. It's much more cost effective to just have 3-5 Powerwalls dedicated to home power backup and load balancing the grid. EV's are for transport, not backup residential power, at least not beyond low powered devices or very limited usage of higher-powered applications.

Isn’t solar thermal a thing over there?, my 2 panels and 200L tank system from Velux can reach 80 degrees C after only a few hours of sunshine and this is in the U.K. which isn’t known for shed loads of sunshine, from March though to October I very rarely need to fire up the heat pump for hot water.

 

[firsttruck]

In southern U.S. (including Puerto Rico) it is fairly common to experience a disaster (hurricane, tornado, Texas freeze, pipeline break, transmission line break, etc) that knocks out power for days , weeks or months yet have sunny skies starting immediately the next day or two.
If you have solar you can potentially storage energy during the day in your power walls & your Cybertruck and then draw down that energy at night or a cloudy day later during the prolonged outage.

The key is having all three: solar panels, powerwalls, and vehicle storage.

Having enough power wall storage for very long outage is very difficult so using your truck would be very helpful. Remember that the immediate days after the disaster even if you had the money you probably would not be able to get more powerwalls so energy in your vehicles might be only other way to stretch things out.

When you have ICE generator & ICE vehicles under some situations you might take some of the gas out of your vehicles to run the generator (assumes you keep enough in vehicle to make round-trip to a gas station still operating).

 

[Crissa]

I suppose it might be useful if you had a fleet of $60K EV trucks to draw from and could reserve one or two for emergency transportation needs but that brings us full-circle. It's much more cost effective to just have 3-5 Powerwalls dedicated to home power backup and load balancing the grid. EV's are for transport, not backup residential power, at least not beyond low powered devices or very limited usage of higher-powered applications.

You draw more electricity to take a shower than most houses do in an entire day.

Your demand that your backup power provide for all possible devices exceeds the vast majority of of backup power systems.

I don't think you make a decent baseline for what's possible. Not only do you not need to take a shower when you're not at your cabin, limiting the amount of power that it requires for standby backup, you've chosen a specifically on-demand system when instead of using more peak power than three houses, you could have chosen a system which meshes with a solar power generation system.
https://www.nrdc.org/experts/pierre-delforge/heat-pump-water-heaters-clean-energy-batteries

Backup power does not need to power everything. Nor should it. Some things don't care if the power blinks but still need it all day, others are just pretty, others need an uninterrupted stream, some things need massive power - like your water heater - and shouldn't be used off-grid. Pick and choose these things, and don't say a system can't work because it is not the grid.

-Crissa

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