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Why is my Vehicle to Grid (V2G) Charger Tripping RCDs?


Hi All.

This is my first post to the Ovo Forums.  I’ve had V2G since December last year and not had a major problem until now, apart from having to switch charger on and off four or five times.

I’ve sent an email to smarthome@ovoenergy.com, but what with Covid, don’t know when I’ll get a response, so thought I’d see if anyone else had a similar problem.

 

Got up this morning around 08:00, and the main house RCD had tripped. I reset the main house RCD and noticed the V2G charger RCD had also tripped which I reset.

I went to check the level of charge in the Leaf, and the car doors wouldn't unlock.

I switched on the V2G charger and the V2G RCD tripped again a few seconds later, but the car doors were able to unlock and I found it had 60% charge.

I unplugged the Leaf, reset the V2G RCD and was able to boot the charger but when I plugged in the car and tried to switch on charging, the V2G RCD tripped. 

Looking at when the car was last charging, it would appear that it tripped around 08:00, when the battery was at 60%, to be at 80% by 10:00.

I switched across to the original Rolec charger (which I kept as backup when the V2G was installed) and plugged in the car.  It was able to charge the car easily.

The V2G charger is now isolated.

 

Strike a chord with anyone?

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Best answer by Bobby_OVO 15 June 2020, 12:33

I’m sorry to hear you’re having issues @Glaikit 

 

What you describe is not an issue I’ve come across before, so I’ve passed this information to our platforms team. They’ll be able to analyse the data we’ve received from the charger during the times of the incidents, which should give us a better understanding of what the issue is. 

 

We’ll respond to your email once we have an update for you and it may be best to leave the unit isolated in the mean time, just to be on the safe side. For anyone with a similar issue, please do the same, and email us on: smarthome@ovoenergy.com,

 

^Bobby

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Hi @Glaikit 

 

I’m flagging this with the OVO Smart Home team, hope to get you a reply later today. 

 

Any other trialists had something similar @D10hul @Karlkb15 @DarrenG @piersjk ..?

I’ve had that many types of faults and number of faults since September I’ve lost count, its no good sitting back and waitIng for someone to fix it, you’ll have to chase it. 

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Well its not a issue I have come across, I would say you have a error somewhere thats sounds like it will need a unit exchange, however I would go and try your car on a public Rapid just to check your barking up the right tree, some of the older leafs have had issues with the V2G mainly down to out of date software on the car (not updated correctly by the dealers ) out of curiosity you say the unit will run ok, but when plugged into the car it trips, also you state when the car is plugged in to the unit the doors don't work and the cars dead ?

This sounds like it could be a car issue as the car is aware something is wrong and tripping out the unit and locking its self out for safety. 

Let us know who you get on at a public charger.  the home type 2 charger is a different system to chademo, the fault might be on the DC charge side not the A/C. 

Userlevel 2

I’m sorry to hear you’re having issues @Glaikit 

 

What you describe is not an issue I’ve come across before, so I’ve passed this information to our platforms team. They’ll be able to analyse the data we’ve received from the charger during the times of the incidents, which should give us a better understanding of what the issue is. 

 

We’ll respond to your email once we have an update for you and it may be best to leave the unit isolated in the mean time, just to be on the safe side. For anyone with a similar issue, please do the same, and email us on: smarthome@ovoenergy.com,

 

^Bobby

It is definitely a charger issue.

The car is a 2018 Leaf, and I’ve taken it to a Rapid Charger and it worked ok.

It means I have to rely on my Rolec smart charger with the ev.energy ap, which is a shame as the Kaluza app is much better.  The ev.energy app does not allow you to set min/max charge.  I assume that is because you cannot get charge level through the 7kW connector.

Thanks to all who replied.

Jim

Well its not a issue I have come across, I would say you have a error somewhere thats sounds like it will need a unit exchange, however I would go and try your car on a public Rapid just to check your barking up the right tree, some of the older leafs have had issues with the V2G mainly down to out of date software on the car (not updated correctly by the dealers ) out of curiosity you say the unit will run ok, but when plugged into the car it trips, also you state when the car is plugged in to the unit the doors don't work and the cars dead ?

This sounds like it could be a car issue as the car is aware something is wrong and tripping out the unit and locking its self out for safety. 

Let us know who you get on at a public charger.  the home type 2 charger is a different system to chademo, the fault might be on the DC charge side not the A/C. 


I think the probability is an error in a pre-production unit (possibly using a beaglebone with open-source software) than in a post production car :grinning:

Jim

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This background info is very instructive @Glaikit .

The whole issue of RCD units tripping is quite complex. As this one only feeds your V2G charger, you might think that this points the finger at the charger itself. But it’s not quite as clear-cut as you might at first suppose.

All cables have some leakage to earth. So there will already be a few mA difference in the current supplied by the Live compared with that returning via the Neutral.

Secondly, each RCD has a specified “trip-time” depending on what it is you wish to protect. A “good” fast-acting RCD can sometimes be caused to trip by a spike on the incoming live feed rather than the circuit beyond it. Such spikes (transients) can be caused by external sources, such as a remote lightning strike, or internal problems such as the back-emf when a motor switches off. The energy stored in the motor coils is discharged back down the cable that supplies it.

There are quite a few lightning storms around at the moment, so bear in mind that could account for what you’ve just experienced. In a couple of days, the problem might disappear… just in time for Kaluza to send an engineer to site and report “no fault found”! :scream:

I have surge-suppressors in my consumer unit to quench any transient spikes coming into the house via the mains supply. They will happily quench up to 40kA of surge current and send it to ground. You might wish to consider having these installed for your house. However, they are only as effective as the quality of your house earthing system. So make sure you get that checked first.

Please ask for clarification on any of the above if you wish.

This background info is very instructive @Glaikit .

The whole issue of RCD units tripping is quite complex. As this one only feeds your V2G charger, you might think that this points the finger at the charger itself. But it’s not quite as clear-cut as you might at first suppose.

All cables have some leakage to earth. So there will already be a few mA difference in the current supplied by the Live compared with that returning via the Neutral.

Secondly, each RCD has a specified “trip-time” depending on what it is you wish to protect. A “good” fast-acting RCD can sometimes be caused to trip by a spike on the incoming live feed rather than the circuit beyond it. Such spikes (transients) can be caused by external sources, such as a remote lightning strike, or internal problems such as the back-emf when a motor switches off. The energy stored in the motor coils is discharged back down the cable that supplies it.

There are quite a few lightning storms around at the moment, so bear in mind that could account for what you’ve just experienced. In a couple of days, the problem might disappear… just in time for Kaluza to send an engineer to site and report “no fault found”! :scream:

I have surge-suppressors in my consumer unit to quench any transient spikes coming into the house via the mains supply. They will happily quench up to 40kA of surge current and send it to ground. You might wish to consider having these installed for your house. However, they are only as effective as the quality of your house earthing system. So make sure you get that checked first.

Please ask for clarification on any of the above if you wish.


Good point. 

The house is well over a hundred years old (but has since been rewired :grinning: )and when they installed the Rolec charger they put in an earth spike.

I did wonder about transients, because two RCDs were tripped. I’ve got a main distribution board, and a separate one for the charger, as it made installation simpler that way.

However, the RCD in the sub-distribution board trips when I try to charge the car from the V2G charger.

So a transient may have damaged the charger, therefore I’ll keep it isolated until asked to do otherwise.  I don’t know, they may have some remote diagnostics which may help.

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Hi @Glaikit and thanks for those clarifications. BTW you don’t need to requote what I’ve written above unless you’re trying to refer to a particular phrase… as I’m about to do!

A key point in what you’ve just written is

when they installed the Rolec charger they put in an earth spike.

That might be correct, but it’s unusual. It suggests that your existing earthing for the house was deficient.

As you work in a technical field, please allow me to expand this in such a way that others might read it at a later date and benefit from the explanation…

Either a house has an electricity supply which provides an earth connection (referred to as PME) or it does not (referred to as Direct Earthing, or TT).

If the supply is TT, then each house requires an earthing rod connected to its Consumer Unit with a 10mm² wire.

diagram courtesy of Western Power Distribution (WPD)

Unless the local Distributed Network Operator (DNO) says otherwise, you should not install your own earthing rod on a house with a PME Supply. This can be dangerous to you and your neighbours in the (unlikely) event of the Feed from your sub-station having a faulty Neutral. The earth is provided for you within the Feed:

diagram courtesy of Western Power Distribution (WPD)

 

This is one reason why local electricians tend to get things right, and large National Companies can fail. The local tradesman will know the Distribution Network of the area, and will be known by the DNO engineers who maintain that Distribution Network.

If your house has a PME Feed, then there will be a Notice to state that on the door/gate to your substation. If the Feed is via overhead poles, then each pole will be similarly marked.

 

Earth rods are a mixed blessing. They keep your house wiring safe, but they also pick up the ground-waves from any surges.

Imagine a lightning strike. If it’s almost a direct hit, then the entire electricity supply to your house will be raised by a million-volts and then fall again. It’s possible that this does no damage. After all, there was no Potential Difference across any piece of equipment!

But if the lightning strike is on a block of flats a mile away and it’s fed from the same substation as you, there will be two surges heading in your direction.

The faster surge travels down the wires at two-thirds the speed of light (the propagation-delay of electromagnetic radiation in copper). However, the ground-wave will be a few mS later because earth and rock are less conductive.

This means your house suffers a see-saw of two large surges. The first raises the voltage of all electrical wiring (and connected equipment) several thousand volts above that on the house earthing.

A moment later, the opposite occurs, the ground-wave arrives via your earth-rod and its voltage is then momentarily higher than the mains-connected appliances in the house!

 

If all operates as it should, your fast-acting trips will fly open. But even so this takes a few mS and that’s a good hundred times slower than the rise-time of a lightning surge!

That’s why I have good-quality earthing and Surge Protection Devices (SPDs) at the point where the mains wires enter my Consumer Unit.

If you want to learn more have a look at Lightning and Surge Protect Devices from Phoenix Contact. They are world leaders in anti-surge technology, with test-labs based in the Black Forest - a geographical area with a very high number of lightning strikes!

I see that this issue has been marked Solved @Bobby_OVO .

Can someone tell me what is the solution?

Thanks.

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The Topic gets marked as “solved” once a Moderator decides that a “Best Answer” has been provided. But as the Author of the original question, you have the ability to reject that Answer if you wish.

Your description of the fault suggests to me that the RCD for the V2G charger feed is running quite close to its trip-current (presumably 30mA).

Since it’s been OK until recently, I’m suspicious that there has been some minor damage due to lightning surge currents. This could be as trivial as a decrease in the effectiveness of insulation around wires/cables.

Since an earthing rod has been installed without regard to the type of earth that may already be provided via the mains incomer, I wonder what might be the effect of temporarily disconnecting that new earth wire from the top of the rod.

I’m unsure of your position as regards warranty from Kaluza if you were to try this. Perhaps @Bobby_OVO can advise?

It this was my house, I’d actually prefer to bring in a local electrician and get earth-loop resistance readings for both earths. That would provide some clear data on which decisions can then be made.

Interesting @Transparent , @Bobby_OVO  what you say.  Since installing the charger Ovo has made the house more susceptible to transients, and the RCDs triggering.

Should I be concerned about the safety of the Ovo installation?  Especially under the current Covid conditions and the lack of activity by Ovid. 

Will Ovid pay for a local electrician to review the work they carried out since it is my understanding that as they did a site survey, and self certified the charger installation they were happy with the situation when they integrated the V2G into the house electrical system which now appears to be dubious.

¯\_(ツ)_/¯

 

 

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Firstly @Glaikit there’s no issue of safety here. What you’ve had installed is “failing safe”, which is what it’s designed to do.

If your V2G installation were in my region of SW England I’d be putting Kaluza’s Installations Manager in contact with the Area-Team technical Manager for my DNO (Western Power Distribution). That would be a quick way to check the earthing characteristics of the immediate locality and see what adverse effects have occurred recently as a result of lightning.

Your DNO is SP Energy Networks, and I don’t have access to their Distribution Maps and Data. However, they could offer such access to Kaluza of course.

We need to remember that this is a Trial. The whole point is to allow these problems to occur and then investigate them.

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We are currently looking in to your issue @Glaikit.

 

I think it is best to isolate the V2G unit until we have been able to diagnose the issue and know the best course of action. If you are still experiencing issues once the V2G is isolated then it is most likely that the issues are not related to the V2G installation.

 

If an electrician attends and determines that the V2G is at fault for continued issues, despite being isolated, then we would cover the cost of that electricians visit once we’ve seen their report.

 

We’ll be in touch via email once we’ve established the best course of action to resolve the problem.

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How does that sound to you @Glaikit ?

I’m a bit puzzled by @Bobby_OVO’s phrase:

If an electrician attends and determines that the V2G is at fault for continued issues, despite being isolated...

If the charger is isolated, then how would an electrician determine that it is the cause of its RCD tripping?

I’m assuming that the RCD in the main Consumer Unit feeding the rest of the house is still ok and working… as long as the V2G charger remains isolated. Is that correct?

How confident would you feel about talking to SP Energy Networks?

In my area it’s highly unlikely that the DNO would make any charge to come and have a look at the newly installed earthing rod and advise if they felt there should be any changes. In fact, the local engineering team would probably leap at the opportunity to have a closer look at a V2G installation! :slight_smile:

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@Transparent This is correct, I only mention what you’ve quoted with the condition that the problems still occur once the unit is isolated. If the problems stop once the unit is isolated then I suggest it is best to leave it isolated until we have diagnosed the issue and have come up with a solution. 

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Thanks for clarifying @Bobby_OVO 

So, @Glaikit - if the main house is ok and its rcd is no longer tripping, then there’s no point you getting an electrician at this point.

That still leaves you with the opportunity to discuss earthing requirements and recent lightning/surges with SP Energy Networks if you wish. They may have useful comments to make.

Update on solution to problem @Bobby_OVO , @Transparent .

As I said in op, the charger was isolated as soon as I identified the source of problem was the charger.  It was replaced a couple of days ago, straight swap out, swap in. Shout out to Craig for coming all the way from Newcastle.

Now operating as normal.

Interesting. This is exactly the same as what’s been happening to mine. I suspect it’s the unit but advised by OVO that it is probably a supply issue. Contacted western power and they looked at set up and suspect the unit as all of the problems are on that circuit of the V2G trip. It’s interesting too, having observed it over the period. It trips out when it gets up to 5.1kw charging rate and over. When it’s lowered ie 4.8/4.9 itv doesn’t seem to trip  I suspect a swap out needed.

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Hey @Kevwalmsley - your post was 4am! That’s taking commitment to provide feedback to the extreme!  :scream:

Having said that… you get a gold star :star: for the most helpful and accurate feedback on the V2G Trial this month.

Let’s just tag @Bobby_OVO to make sure he sees this on Monday morning.

Thanks @Transparent cant sleep for fear of not having a charge in the morning haha. Seriously though being a night owl has meant I have been able to do extra monitoring. It certainly appears that when it gets up to 5.1kw charge rateis when it trips out. 

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Hi @Kevwalmsley , we are currently reviewing the information that you provided to us via email and will determine the best course of action based on this. We’ll be in touch with the next steps as we have them.

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How do I get help?

My V2G charger seems to have “tripped” the RCD and on reset does it again. the lights on a separate circuit surged with power when you hear the loud bang as the v2g goes pop. 

 

Sadly., it may be something more serious upstream as my other charger that was on a isolator switch which did work post bang now ALSO trips the rcd! 

 

where do I start and HELP!!!

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Hiya @Jequinlan ,

Have you maybe considered giving Kellogg's a call by any chance? I'm sure they'll be more than happy to send Snap and Crackle to your house to join the party! :rofl:

But on a more serious note, I think you may well need to get help from Indra before trying to use either charger again. If you're able to get in touch with them, that's worth doing as a starting point 

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@Blastoise186 i have posted a mail to kaluza, but no reply now so posted here to see if theres a phone number or something...

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