Connecting a V2L car to a house as a battery.

[decrep]

Yes That's what I've been saying, I have a PV panel inverter, I don't have a battery.
I haven't played with the inverter at all, I assume it needs to know what the fully charged battery voltage is, so it will stop charging. If I then set that to the power supply output, there shouldn't be a problem.
Thanks John, I'll investigate the possibilities.

 

[Jonoffun]

Break before make switch using either grid or V2L, so no issues with syncing the two up? Manual switch over, keeping it simply controllable. (Although useable earth could be an issue - keep earth connected in switch ? ?)
How obvious is it I really have no idea what I'm talking about? Qualified electrician too. ??

Could that work - that was what I was thinking. 1) Power cut - switch off the grid at the Consumer Unit....plug in car to any house socket, set car to export - car battery runs house.....OR 2) if you have a home battery and solar and an inverter....the car "emulates" the grid - the home battery continues to work and the car takes up any slack....When the grid power comes back......switch off the car, unplug....switch back on the grid at the Consumer unit - is that possible?? Surely the earth is supplied by the house bonded earth?

What are your thoughts?

 

[Bam Bam]

Could that work - that was what I was thinking. 1) Power cut - switch off the grid at the Consumer Unit....plug in car to any house socket, set car to export - car battery runs house.....OR 2) if you have a home battery and solar and an inverter....the car "emulates" the grid - the home battery continues to work and the car takes up any slack....When the grid power comes back......switch off the car, unplug....switch back on the grid at the Consumer unit - is that possible?? Surely the earth is supplied by the house bonded earth?

What are your thoughts?

Not an electrician but isn't the output from the car about 6amps? And your house electricals are set up for 60-100a?

We have a backup battery system but that can only output 16a so you have to make sure there are no big draw items (or at least not more than one at a time) or else you'd overburden the inverter. It would cut out but doing that wouldn't do it any good and would probably shorten its life.

I wouldn't want to shorten the life of the inverter on my car.

We have used the car as a backup (when the backup system was being installed) to run the router and a lamp.

Used an extension lead and it worked great, so it can provide a backup of that kind no problem.

 

[Jonoffun]

I have two batteries, a 7kWh one as part of my Growatt Solar installation and my DIY 14 kWh system. Both inverters are grid tied and they work reasonably well together. My V2L system works by having a 3 kW battery charger connected onto the DIY battery. A reasonably continuous 3 kW was taken from the MG5 feeding a LifeP04 battery charger which was connected to the DIY 14 kWh battery, the same connection goes to the Victron Inverter which enabled the system run as if it had a 44 kWh battery connected. We ran heat pumps, 2 ovens and cooking rings as well as the immersion heater all day. Because I was putting power from V2L into my house system via the battery connections, the whole house was powered from the inverters and it was easy and convenient to do, no separate plugs on appliances etc, just carry as if it was grid powered.

What a great solution. I have a growatt inverter and solar PV. If we have a power cut - regardless the whole lot goes down as the inverter needs grid to work. IF, I did the following - might it work....a) Power cut, b) set car to discharge, c) switch off the grid at the Consumer Unit d) plug car into any plug in the garage. IF I did that, would the growatt inverter "see" the car as "grid" and then run the house from the batteries of the house....When the grid comes back, disconnect the car, switch the grid back on at the Consumer Unit.... The reason I like your solution above is that I would need to buy 40kwh extra batteries to run an ASHP in winter and even though it would be cumbersome you could use your solution to beef up the home batteries in winter...without spending a fortune. Would the Growatt inverter be in synch with the car inverter?

 

[mg4]

What a great solution. I have a growatt inverter and solar PV. If we have a power cut - regardless the whole lot goes down as the inverter needs grid to work. IF, I did the following - might it work....a) Power cut, b) set car to discharge, c) switch off the grid at the Consumer Unit d) plug car into any plug in the garage. IF I did that, would the growatt inverter "see" the car as "grid" and then run the house from the batteries of the house....When the grid comes back, disconnect the car, switch the grid back on at the Consumer Unit.... The reason I like your solution above is that I would need to buy 40kwh extra batteries to run an ASHP in winter and even though it would be cumbersome you could use your solution to beef up the home batteries in winter...without spending a fortune. Would the Growatt inverter be in synch with the car inverter?

I guess it would work, if the grid to house connection is disconnected by a manual hardware switch, that does not connect the house to the grid once the power cut ends.

But you would need to ensure your house does not pull more from the car than the car can deliver. Could be a simple fuse but not sure if that is enough.

I am not an electrician though

 

[Coulomb]

Using a house outlet as a power inlet is a bad idea. The resultant plug is live at the pins; it's called a "suicide cord" for a reason.

And as others have pointed out, the car's V2L is suitable for only one appliance at a time, or a few low powered ones. You generally can't control when heavy items like a water heater might come on and overload it.

 

[johnb80]

What a great solution. I have a growatt inverter and solar PV. If we have a power cut - regardless the whole lot goes down as the inverter needs grid to work.

Usually, the inverters have an emergency power system built into them. This comes alive when the grid has failed and can be used up to the maximum rating of the inverter.

IF, I did the following - might it work....a) Power cut, b) set car to discharge, c) switch off the grid at the Consumer Unit d) plug car into any plug in the garage. IF I did that, would the growatt inverter "see" the car as "grid" and then run the house from the batteries of the house....

NO. The inverter wouldnt 'see' any of the loads with respect to the grid because the back feeding is being done after the CT or Generation meter. There is also the danger of damage to the V2L in the car, the inverter takes the load by increasing it's output voltage which the V2L may not like.

When the grid comes back, disconnect the car, switch the grid back on at the Consumer Unit.... The reason I like your solution above is that I would need to buy 40kwh extra batteries to run an ASHP in winter and even though it would be cumbersome you could use your solution to beef up the home batteries in winter...without spending a fortune.

My solution bypasses the complication of feeding V2L into the inverter supplied lines.

Would the Growatt inverter be in synch with the car inverter?

I suspect the output of V2L is a modified sine Wave which inverters wont like.

The other thing you should be aware of is many of the Growatt inverters will only output 3 kW when running on battery supply. what model of Growatt do you have?

 

[Jonoffun]

Yes my Growatt inverter has the EPS feature, but you need to set it up and have a separate CU with "essential" circuits. I was trying to avoid that expense and complexity. "NO..The inverter.........like.." comment you made - gives me enough caution not to try anything. Maybe if there was a power cut I could disconnect the mains AND switch off the Growatt /home battery feed....and plug the car into the house sockets....the house runs on far less than 2kW if you don't go mad with kettles etc....and might be sufficient to hold over if there was a prolonged power cut that the DNO said was going to last days! I prefer your solution but I will sit on my hands until the technology catches up. If I were running a ASHP I would add extra batteries and ensure the car could charge them during the heaviest times in winter - just like you have done. I am not an electrician. Just not worth the risk of screwing anything up! - Thanks for the feedback and providing a great idea to possibly copy.
Oh SPH6000 inverter and 3 x 3.3 kWh Growatt batteries.....maximum discharge from the batteries is 3kWh each.

 

[johnb80]

Yes my Growatt inverter has the EPS feature, but you need to set it up and have a separate CU with "essential" circuits. I was trying to avoid that expense and complexity.

You can set it up a different way with a generator switch on your incoming supply, the Growatt wired to the generator part of the switch. Automatic switches are available such as this one:

Transfer Switch

This one would automatically disconnect from the grid supply and connect to your EPS output. When the grid power returns it disconnects from the EPS and connects back to the grid. I have a similar one on my system and it works as expected.

"NO..The inverter.........like.." comment you made - gives me enough caution not to try anything.

An appreciation of the bigger picture and consequences thats all.

Maybe if there was a power cut I could disconnect the mains AND switch off the Growatt /home battery feed....and plug the car into the house sockets....the house runs on far less than 2kw if you don't go mad with kettles etc....and might be sufficient to hold over if there was a prolonged power cut that the DNO said was going to last days!

It's not dramatically expensive to put the changeover switch in and a lead that the car can be plugged in to provide house power. A little bit like a caravan electric hookup lead is all you would need to plug into the V2L and the house.

I prefer your solution but I will sit on my hands until the technology catches up. If I were running a ASHP I would add extra batteries and ensure the car could charge them during the heaviest times in winter - just like you have done. I am not an electrician. Just not worth the risk of screwing anything up!

It's easy on tariffs like Tomato Energy Lifestyle EV to charge both car and house batteries overnight, we regularly max out our supply in doing so.

Thanks for the feedback and providing a great idea to possibly copy.

Always happy to help.

Oh SPH6000 inverter and 3x3.3kwh growatt batteries.....maximum discharge from the batteries is 3kwh.

It was a huge disappointment for me when I discovered that the maximum output of the SPH6000 on batteries was 3 kW. I'm planning to remove my Growatt system this year and replace it with another Victron system (Multiplus II and suitable MPPT chargers) to get rid of Growatt and their odd methods (they dont like anyone communicating with their inverters with the likes of Home Assistant) etc.

 

[charlie bravo]

Ok, I know the difference between V2G and V2L.

You cannot connect a car with V2L to the house power supply because it cannot sych with the phase of the grid and an explosive outcome will result.

Would it instead be possible to connect via a DC convertor to a solar DC invertor instead to power the house?

Surely there must be a way!

Hi get a connector on eBay, you can then use extension lead, to run anything up to 2.4 kW, and if you overload it, just reset again.

 

[johnb80]

Hi get a connector on eBay, you can then use extension lead, to run anything up to 2.4 kwh, and if you overload it, just reset again

It’s just not very convenient connecting the central heating, fridge, freezer, TV and router. Lighting would be an issue too.

 

[Jonny2300]

I've connected my V2L (MG4) to my home via a change over switch. However connecting to the house trips the MG supply. Even when everything in the house is turned off. Some have mentioned earthing may be an issue but that's over my head.

 

[johnb80]

I've connected my V2L (MG4) to my home via a change over switch. However connecting to the house trips the MG supply. Even when everything in the house is turned off. Some have mentioned earthing may be an issue but that's over my head.

So if you turn off your consumer unit (fusebox big switch), operate your changeover switch and connect your MG it still trips? If so you have a wiring problem with your changeover switch.

If it doesn't trip in the above, switch on the fusebox if it then trips, you have a load that is too high for the MG, probably things on standby when theyre first powered take a bit of a surge. Switch off all of the MCB's (circuit breakers, reset the MG supply and switch the circuit breakers on one by one until the MG supply trips you will then know which circuit causes the overload. Turnoff all appliances at the socket of unplug, restore MG supply and continue until all MSB's are back on. Switch on the appliances one by one until it trips again and bingo, you've found the culprit.

 

[Jonny2300]

Thanks for your easy to understand reply. I also tried connecting my mg supply after the change over switch. As soon as I pull down the big red master on the consumer unit it trips the car. Even with all other RCD s off. It does not like being connected to the house.

 

[johnb80]

Thanks for your easy to understand reply. I also tried connecting my mg supply after the change over switch. As soon as I pull down the big red master on the consumer unit it trips the car. Even with all other RCD s off. It does not like being connected to the house.

There's definitely an issue between your incoming supply / changeover switch and the MG. All relatively simple and it may well be to do with the earthing arrangements. Do you know if the changeover switch isolates the earth continuity from the grid supply and what sort of earthing arrangement is used on your grid supply?

 

[Everest]

Thanks for your easy to understand reply. I also tried connecting my mg supply after the change over switch. As soon as I pull down the big red master on the consumer unit it trips the car. Even with all other RCD s off. It does not like being connected to the house.

Hmmm. I feel we are going round in circles here. I agree with everything @johnb80 has said above... BUT, I already asked you the questions about earthing in my replies to you on the other thread where you asked the same questions last month

see - V2L Test. 7kW output...

With all due respect, please get a sparky in to sort your issue out. There is no point asking questions on one thread of a forum, getting some answers, and then asking the same questions on another thread with the cop-out...

Some have mentioned earthing may be an issue but that's over my head.

If earthing is 'over you head', please don't risk the safety of yourself or loved ones - get a professional in.

 

[Jonny2300]

Yes earthing is over my head....the house has a earth rod and the change over switch has an earth. I asked the spark who fitted the change over switch and EV charger. But it's not his area I don't think why my EV drops out when connected to consumer board. I was hoping for an easy solution. Don't mean to upset anyone. Not sure who I could ask professionally to fix this. I don't think most electricians have experience with v2l to home issues. Appreciate advice given.

 

[Jonny2300]

Yes earthing is over my head....the house has a earth rod and the change over switch has an earth. I asked the spark who fitted the change over switch and EV charger. But it's not his area I don't think why my EV drops out when connected to consumer board. I was hoping for an easy solution. Don't mean to upset anyone. Not sure who I could ask professionally to fix this. I don't think most electricians have experience with v2l to home issues. Appreciate advice given.

Hopefully this helps

 

[johnb80]

Hopefully this helps

Where does your MG plug into the system?

Do any of the MCB's trip in the consumer unit?

 

[Jonny2300]

The v2l cable would be wired into change over switch. It's not in currently as I had to revert to extension lead. It enters bottom right. Switch handle obscures CAR label. No MCBs trip on consumer unit. Box on bottom right is RCD for Zappi charger.