Q&A - EV charging and thunderstorms

I wasn’t aware that EV chargers advise not to be used in thunderstorms. I don’t see how the risks would be any different to using any other electrical device in the home during a thunderstorm. Moreover the car itself has better isolation due its rubber tyres.

Anyway, there are several other Topics here on the Forum where we’ve discussed lightning surge suppression and what is or isn’t present in the V2G Charger.

V2G Charger stopped working - No Power

OVO Smart charger stopped working

V2G charger tripping RCDs

Curiously Kaluza haven’t yet come back to us to confirm what surge protection is present in either of the Indra chargers they install. It would be interesting to hear from @Bobby_OVO about this.

Some good questions here, and I think we have the community members here to answer them all! 

Forgive the spam tagging but I’m going to mention all of our confirmed ‘EV volunteer’ badge earners for a bit of knowledge pooling:

@IbrahimEV @sylm_2000 @NeilG @jp1 @Andras @D10hul @DarrenG @Mikeyoung @Peetee @aaronr @PeterR1947 @Delboy 

I am sorry but this is all a bit of an EV myth and totally incorrect.

1. Charging a car whether at home or public charger in a thunderstorm is no less safe than actually you being out in that thunderstorm. Assuming you are physically outside then you are likely to be a preferred path to ground for lightning than the charger or the car.
2. As above the real risk is that you are providing the prefered path to ground by being physically outside. 
3. There is nothing to prevent the charging from occuring during a thunderstorm. That said lightning can disrupt power from the sub station if it is “tripped” due to a strike. It may also be possible for network connections to be impairred that could impact a public charger.
4. If I had a low battery during a thunderstorm I would probably pull over and wait in the car till the storm passes. Cars act as faraday cages so are safe places to stay. Getting out of the car, say to charge, puts you in harms way. As previously stated that has nothing to do with car or charger just the fact you are physically out in the open. 
5. V2G chargers have to pass the same stringent tests as anyother commercially available charger so should have the same level of safety.

They always say you should not drive a Golf in a thunderstorm as that is dangerous, or is that you should not play golf ……….  :-)

My thoughts are that charging is probably not the problem, but the earth connection It provides probably will be. Actually disconnecting the car would probably be. The connection to earth will mean the car is no longer insulated and isolated. The issue will be that if the local grid or car get struck, a very large potential will be placed across the network and as a result current flow and energy will be released…. the sensitive electronics in both car and charger will be toast! This is why pulling plugs from wall sockets is also advisable. A friend from work had a near miss strike few years back… a pole not far away was hit and he lost all the connected electronic devices in the house! Phones, TV, radios, etc..

I think you’re on the right tack there @Andras 

There was a response here on the Forum in 2019 stating that the Indra chargers both contained surge suppression.

I then did some further research and discovered that integral surge suppression is part of the standard for the CHAdeMO connection. That’s not the same as having anti-surge protection devices for the charger itself!

The other puzzlement I still have is the ongoing debate about the need for chargers to have an earth connection “for safety”.

If your house is supplied with PME from the sub-station, then adding an earth is a no-no!

However…

… if the charger had integral surge suppression, then this may indeed require a path to earth because it’s got to find somewhere to route those pesky electrons.

At the moment I think there is a confusion being caused in the debate as to whether the charger itself requires an additional earth (stake), or whether there is a need for an earth connected (solely) to a pair of internal transient suppressors.

The hypothesis I’m putting forward is that perhaps an EV charger should have two separate earths. When being installed in a house that does legitimately have an earth stake, then those earths could be combined.

Thanks for this @PeterR1947 ….

So presumably the suggested installation of an earth rod is instead of using the earth provided by the PME isn’t it?

Thanks @PeterR1947 

To help others understand what we’re discussing, here’s the diagram which I pictured in my head when I suggested above that an EV charger could have two separate earths.

So I’ve conjectured that the case/electronics has an earth stake, and that there are internal lightning/surge suppressors to quench whatever nasties arrive via the live & neutral. These too need a path to earth.

I’m not saying this is how it should be. I’m merely putting the hypothesis forward for discussion.

Also, just checked this morning at the relatively new polar charger in devon and no comments about thunderstorms on that one. I think it may be just to indeed protect the v2g more (or just being overcautious, like the do not immerse laptop in water type warnings.)