Powering your house from a V2L-capable EV

[Hedges]

3-Potentially mortal: If your EV have a 400V battery, connect directly a 400V output of your EV to a MPPT input of the inverter.

My system is AC coupled (Sunny Island + Sunny Boy)

What I would like to do is connect 400V battery to PV input of another Sunny Boy (or other GT PV inverter), with its frequency-watts range set to curtail 100% before the GT PV inverters that actually have PV panels start do do so.

Ideally this would be done with a bidirectional inverter, so before photovoltaic production is curtailed, the EV battery charging is ramped up.
What I'm currently hopeful for is Sunny Boy Smart Energy (3x PV input + 1x battery input) can do this. It has both PV and battery, so diverts surplus PV (beyond inverter capacity) to battery. What I don't now is how all that is controlled with AC coupling - want battery drain curtailed first, then battery charging ramped up, then PV production curtailed.

 

[RP67]

to me there is 4 possibilities:

1-Easy low power: 12V to 120V or 240V inverter plug to the generator 120 or 240V input. 12V EV battery to generator input.
2-Not so easy: Use proper DC-DC converter connect to the 12V battery of the EV to charge the house 48V battery.
3-Potentially mortal: If your EV have a 400V battery, connect directly a 400V output of your EV to a MPPT input of the inverter.
4-Super complex: Use the DC port (CCS or Tesla) of your EV to feed a MPPT input of your inverter.

All this is at your own risk. You can brick your EV or worst.
Personally, I did #3 with my Bolt EV. I used the HVAC compressor 400V output to feed my inverter MPPT.

360V DC input split phase 120V/240V AC inverter

very interesting indeed thank you. The GWxxxxA-BP checks a lot of boxes: grid-tie capable, high voltage DC (~450vdc), USA split-phase AC, AC-coupling with frequency-shifting, waiting for price and delivery quote. Please let us know what you find out!

diysolarforum.com

Sorry, I forgot to mention my EV supports V2L, up to 2kW (on paper), so I have 230V output from the charge port.

 

[Hedges]

Then just feed that to a battery charger, set to lower voltage than your hybrid.

 

[zanydroid]

In my understanding, the generator can be on while the system is connected to the grid, as long it is set to DC coupled (there are options for AC or DC).

This would require either separate charger and inverter circuits (so both can be used at the same time) or running from grid when charging from V2L.

It’s also not a very automated ESS. You will have to manually switch to charging the car.

Another thing to watch out for is that V2L usually bonds neutral to ground within the car with GFCI/RCD.

However I saw tests with 7kW load when it tripped.

Who tested it (knowledge level/methodology problems?) How long did they run the load for? There could be an internal breaker that trips. Thermal trip might take a while.

Overloading inverter is pretty fast so this does indicate that it has a lot of headroom. But it may not be easily usable headroom.

 

[RP67]

This would require either separate charger and inverter circuits (so both can be used at the same time) or running from grid when charging from V2L.

It’s also not a very automated ESS. You will have to manually switch to charging the car.

Another thing to watch out for is that V2L usually bonds neutral to ground within the car with GFCI/RCD.


Who tested it (knowledge level/methodology problems?) How long did they run the load for? There could be an internal breaker that trips. Thermal trip might take a while.

Overloading inverter is pretty fast so this does indicate that it has a lot of headroom. But it may not be easily usable headroom.

The car perspective, it has a different plug which connects to the charging port, and discharge manually needs to be enabled (including discharge limit on the battery). So it is charging, or discharging the battery. I guess it can be through the onboard inverter (bi directional, perhaps).

The test was pretty sophisticated (from the MG4 forum):


"We were told the MG4 output only 2.2kW,
Our old Kia EV6 output 3.5kW.
Today we decided to push them as far as we could..
With a meter on the input, we ran 2x 600W IR Heating Panels f+ 1x400W IR Heating panel for 1.6kW.
At the same time boiling a 2.5kW kettle and running a 2kW induction cooker hob
General Load of Lights TVs and Computers plus other ancillaries 800W.


Gave 6.9 kW output. Ran that stable with no issues, threw on a toaster and it kicked out and shut down, started up again as soon as the toaster load was removed.

So it seems the MG4 is happy with a 7kW output. Much much better than expected."

 

[zanydroid]

The car perspective, it has a different plug which connects to the charging port, and discharge manually needs to be enabled (including discharge limit on the battery). So it is charging, or discharging the battery. I guess it can be through the onboard inverter (bi directional, perhaps).

Sure that is how it works on Hyundai/KIA cars too. So it’s not easy to switch the car between the two modes. Best case is to add a handcrafted Type2 plug that will fool the car into charging or discharging mode.

The test was pretty sophisticated (from the MG4 forum):


"We were told the MG4 output only 2.2kW,
Our old Kia EV6 output 3.5kW.
Today we decided to push them as far as we could..
With a meter on the input, we ran 2x 600W IR Heating Panels f+ 1x400W IR Heating panel for 1.6kW.
At the same time boiling a 2.5kW kettle and running a 2kW induction cooker hob
General Load of Lights TVs and Computers plus other ancillaries 800W.


Gave 6.9 kW output. Ran that stable with no issues, threw on a toaster and it kicked out and shut down, started up again as soon as the toaster load was removed.

So it seems the MG4 is happy with a 7kW output. Much much better than expected."

That doesn’t say how long it ran for so we don’t know if there is thermal breaker in the mix.

With the toaster data point that indicates the reset at 7kW was probably due to something in the inverter or eFused. If eFused or inverter logic it is possible a car update that reaches down to that level can change the behavior, as those are presumably programmable.

Another important datapoint is how the OCPD is reset.

Anyway it’s nice for the car to be able to put out more than the nameplate but I think only the nameplate can be counted on.

Also the maximum correct amount of current needs to be based on the plug type and fusing methodology for appliances. In the U.S. appliances depend on the house for fusing and you are not allowed to plug into a circuit with higher ampacity. The rejection is done by plug shape. So I wouldn’t really want V2L to allow more than 20A, as that would violate code, and if a EV is accidentally sending out more than 20A it would likely be patched in an update

 

[RP67]

Yes all these valid points. My idea to use the car as a backup when the network is down, or something like that. Charging up the house battery would be used in a case of an emergency. My solar generation is pretty much enough to get through the day (expensive power) with the topup overnight (cheap power) even winter time. during summer, I don't buy any power. But, occasionally we have earthquakes, devastating storms which cuts the powerlines, and good to know what resources I have, if you know what I mean.

 

[zanydroid]

Ok I think V2L is a great backup. That is my game plan.

It would probably be most efficient to use the V2L as a grid assist AC source, otherwise you have to pay an extra conversion overhead.

 

[OffGridForGood]

Ok I think V2L is a great backup. That is my game plan.

Batteries are expensive, may as well get a big one that also drives you around LOL

 

[zanydroid]

Batteries are expensive, may as well get a big one that also drives you around LOL

There was someone on a forum asking about using a dolly-style power bank to charge an EV… I don’t think you should even consider that unless the power bank is self propelled. Like a golf cart loaded with server rack batteries

 

[OffGridForGood]

There was someone on a forum asking about using a dolly-style power bank to charge an EV… I don’t think you should even consider that unless the power bank is self propelled. Like a golf cart loaded with server rack batteries

I figured since my ESS is inside the workshop, near the automotive door, I put one charger inside the shop, just drive right in and plug in the EV inside. {ie rather than making a dolly for the heavy batteries, just let the car do what cars do (drive) and put the charger beside the stationary ESS where the car can access it in a garage area.}

 

[zanydroid]

I figured since my ESS is inside the workshop, near the automotive door, I put one charger inside the shop, just drive right in and plug in the EV inside. {ie rather than making a dolly for the heavy batteries, just let the car do what cars do (drive) and put the charger beside the stationary ESS where the car can access it in a garage area.}

Yeah, anything to avoid moving the batteries by handcart or horsecart.

That other silly forum thread was about charging the EV in a situation where you "can't" add L1 or L2 charging infrastructure. It almost sounded like they wanted to handcart it down from charging in their apartment. Either a troll or a unfortunately naive post.

I'm not sure how that approach can be made scalable to a whole building. As one-off performance art that somewhat functions, I think stacking 1 ton of server racks into a golf cart might work OK.

 

[RP67]

Ok I think V2L is a great backup. That is my game plan.

It would probably be most efficient to use the V2L as a grid assist AC source, otherwise you have to pay an extra conversion overhead.

That's right, however I'm rather relying on my Deye Hybrid inverter than the car's built in inverter. Probably less expensive to repair/replace. And again, it is all depends on the given situation. Summer time, no need for massive AC output, however winter time, I would prefer to get the heating system on (that is about 1.2kW itself).

 

[zanydroid]

That's right, however I'm rather relying on my Deye Hybrid inverter than the car's built in inverter. Probably less expensive to repair/replace. And again, it is all depends on the given situation. Summer time, no need for massive AC output, however winter time, I would prefer to get the heating system on (that is about 1.2kW itself).

Yes I’ve been worried about replacing that module too. They were in short stock in the U.S. past two years. There’s another thread about how EVs should have hardware changes for V2X so that any overloaded safety components are easy to replace.

I also have gas backup, but direct vented insert in one corner of the house so it needs help from the blower to circulate.

My heatpump takes 1.5kW usually so it’s not easy to power just from V2L.

 

[MikBurling]

Yep, you can certainly buy ICE generators that are also not suitable as home backup solutions. I wouldn't use a 3.5kW generator for that either. I mentioned it because you can get 2x the solution for $245.99. The Hyundai V2L adapter is $259.99.

The key phrase here is "below the V2L power limit". Given that power limit, using phrases like "power your home" are disingenuous. Unless your home is a box with a mini-fridge and an induction hotplate; only used on low.

Honest alternatives are more like "power your fridge", "power your freezer", or "use your microwave" while the power is out. Just don't try to do more than one of those at the same time .

Put another way, it can definitely work in a pinch to literally keep the lights on for a long time. Just don't ask it to power more than 1.5kW (1 standard 120V circuit). The fridge, microwave, HVAC blower, sump pumps, etc are all on dedicated circuits for a reason. My sump pumps are on multiple 20A circuits, so V2L wouldn't work for me, to just do that.

I've enjoyed this thread. I used the 1500W 120V inverter in my PHEV to power a gas forced air furnace and a couple fridges during a recent day long power outage. Best thing is a full tank of gas (wasn't needed) on top of what was in the HV battery. No expectations on being able to use in a whole home sense.

Working on building an off-grid system that would largely negate this use case for me.

 

[GXMnow]

My whole thinking on V2L is to be able to use a portion of the car battery as a house battery. Most of the time, I get by just fine on my 36 KWH battery bank. But if you know there is bad weather coming, you could fully charge up the car, and by having an extra 20 or 30 KWHs available, you could make it an extra day or 2 with bad solar production, or last an extra couple days off grid if the grid went down. Even being able to pull just 1,000 watts from the car would be good for most uses. I would have the car just charge my home battery. It does not need to do it fast, just put power in to keep up during a grid failure or to cover bad solar production.

Just one way, to the car, does help at times. Instead of pushing energy to the grid, push it into the car. Or in the case of my DC panel system, when my home battery is full, it has to curtail and just throw away energy. If (when) I get a plug in car, I will typically leave it at 80% most of the time. Then if the home battery goes full, the extra can then go to the car battery. I would set it up as a diversion load of sorts.

 

[ksmithaz1]

I'm sorry but I think this is kind of dumb across the board. Maybe in a pinch with no other alternatives, but it seems seriously impractical in this mans mind. So I'm going to buy a $100K Ford Ligtning or something. I'm going to charge it up, it will now go 250 odd miles, and then hook it to an inverter and bleed off it's charge to run my refrigerator and house because I'm too cheap to buy an $2500 rack with 10KWH of batteries dedicated, so now I only have 200 miles of drive-ability, or less if I wasn't full to start with. So what do you do if you start to run out of juice in the Truck? Hmm, unplug, be without while you drive over to an EA station and dump $0.50/KWH into it, then drive home and plug back in? What if the EA is down too?

I can't see any reason I would ever really want to be in a position to need to do this. I think it's "KEWL" and "NEATO" and interesting, but if I need to drive my darn car, I want it full of energy. I'm sorry, I guess I'm just a bit off. So, having the ability to plug in a portable radio or something on a camping trip? Sure, just don't fall asleep drunk and drain your battery below where you can't leave. Anything more significant, I'm not going to use my car.

I'd rather just have an even bigger dedicated PV battery if needs demand. I mean you still have to get an inverter, and wire everything up right? All you are doing is tapping the battery of your transportation device because you are too cheap to just buy a battery. If it get's to the point I'm finally out of power, I'd rather have a generator than suck the power out of my transportation. I doubt I would ever even consider this.

 

[zanydroid]

I'm sorry but I think this is kind of dumb across the board. Maybe in a pinch with no other alternatives, but it seems seriously impractical in this mans mind. So I'm going to buy a $100K Ford Ligtning or something. I'm going to charge it up, it will now go 250 odd miles, and then hook it to an inverter and bleed off it's charge to run my refrigerator and house because I'm too cheap to buy an $2500 rack with 10KWH of batteries dedicated, so now I only have 200 miles of drive-ability, or less if I wasn't full to start with. So what do you do if you start to run out of juice in the Truck? Hmm, unplug, be without while you drive over to an EA station and dump $0.50/KWH into it, then drive home and plug back in? What if the EA is down too?

I can't see any reason I would ever really want to be in a position to need to do this. I think it's "KEWL" and "NEATO" and interesting, but if I need to drive my darn car, I want it full of energy. I'm sorry, I guess I'm just a bit off. So, having the ability to plug in a portable radio or something on a camping trip? Sure, just don't fall asleep drunk and drain your battery below where you can't leave. Anything more significant, I'm not going to use my car.

I'd rather just have an even bigger dedicated PV battery if needs demand. I mean you still have to get an inverter, and wire everything up right? All you are doing is tapping the battery of your transportation device because you are too cheap to just buy a battery. If it get's to the point I'm finally out of power, I'd rather have a generator than suck the power out of my transportation. I doubt I would ever even consider this.

I don’t really buy your hot take on this compared to my personal analysis and experience

I live in town so I don’t have range anxiety. Obviously this is a variable situation , YMMV

V2L on my car has a low Soc cutoff that can be configured in a UI adjacent to turning it on.

For V2H it’s an emergency an alternative to a portable solar generator bank since you already have the EV. That’s a strict profit vs buying it if you have no other use for one. I could have saved $1000 vs buying a generator last year for the power outages here.

If winter power outages are less than 2 days I can use the car to make it through without powering up generator and going out for fuel for it. Otherwise I need 24kWh per day to run heat. I cannot make up that deficit with more solar panels since my property is maxed out. The ESS sweetspot for arbitrage for my property is 15-30 kWh so increasing that size isn’t a good value prop unless it displaces other equipment spending

Fixed batteries are quite expensive in a UL9540 enforced state. $2500 is not realistic for a few years. Also some of us don’t have space for solar power rooms that can hold unlimited batteries.

 

[BarrieM]

I live in France and own an MG Marvel which has a 70kwh battery and V2L. We had a 30 hour power outage recently and ran my Gas Combi Boiler for heat/water, 2 fridges, freezer, TV, internet and lights no problem at all from the car. Combined maximum draw was less than 1.5kw and I only used 3% of the battery but once power was restored I tried to test the cars viability and was able to draw 5kw without it complaining. It's a simple no brainer if you have the vehicle and no batteries ?

 

[pollenface]

My off grid setup charges my EV ... personally I'm against V2L, i want the fuel to stay in the car.