This post will be updated as I find out more information and will be marked with the date of edits

So with all of my EV Experience so far there's been one issue which is a major issue with my car that I am trying to get rectified.

The issue is that when I try to charge on a Rapid Charger that the car crashes out charging and produces what's known as a Battery Charging Impossible.


Summary of the issue
My car fails to charge on 43KW Rapid Chargers using the Type 2 AC connector. The Renault Zoe only has this connector so I can't use CHAdeMO or CCS, but it does support charging at a full 22 or 43KW depending on the engine (Of which mine should be the 43KW).

So far this has happened a total of 4 out of 6 times of attempting to charge on a 43KW Rapid. Once leaving me stranded and had to call out recovery, the second luckily had a slower 7KW post next to the rapid which I was able to use to get home. The 2nd two times were while trying to diagnose the issue myself.

However I have not had the issue on slower charging posts.

Why is this an issue?
Rather than being smart in the software the car will just keep trying to pull a full 43KW, In my case it seems if the car was smart enough to instead reduce the speed to under 30KW then I would be able to charge which while it would be slower would mean that I wouldn't get stranded. And I could accept to a certain degree.

The issue is that on some routes there is no option apart from either a 7KW charger which is too slow, or a 43KW charger which would trip the car.

A little bit of terminology for things that might not make sense:

  • CanZE - An app for your phone that uses an OBD Dongle to get diagnostics information, but specifically designed for Renault Zoes & ZE Cars.

List of all of the attempts

Universal across them all
The exact symptom is the car will start to charge, (easy to notice as the Zoe has a really bad case of coil whine) and then cuts out after around 3-5 seconds.

It will try to do this around 2-3 times and then crash out with the BCI error.

Attempt 1 - Failure - Ecotricity at Newmarket Services November 2018
I had decided to attempt my first long journey to visit my Grandad, there was one Rapid on the route and I got to it with 0 miles left on the range just in time. My panic was thinking that it was going to be blocked, or have a hybrid charging but I got to it and it was clear!

I plugged my car in and bam I got hit by the error, I tried quite a few times over a time span of 2 hours while I waited for the recovery truck to arrive. Holding the cable up, leaving it locked and unplugged for 20 minutes, resetting the charger with support. Nothing kicked it in to charge.

I phoned up the dealer the day after and booked it in to be seen to, however members of the Zoe owners club said it was the charger at fault and to try antother rapid. At the time the only one was in Norwich that I could get to.

Attempt 2 - Success - Podpoint at Lidl Norwich November 2018
So a few days after I decided to go to Lidl, I drove a bit slower as while I left home with a full charge I wanted to have enough charge to get back home if it failed. When I got to the charger it worked straight away with no issues.

Two things were the case here, because I drove slower I arrived with a reasonable % of charge already in the car. And I suspect the batteries were cooler. However I didn't have any diagnostics information so can't confirm these.

Because of this I did then accept it was the Ecotricity charger, quite a few people report faults with them so I accepted it could have been despite ecotricity saying there was nothing wrong with it.

Attempt 3 - Failure - PodPoint at Lidl Norwich 27th January 2018
2 months later, I went to charge at the Pod Point in Lidl again as it was the first time going back to Norwich since December and the first rapid since as all of my journies had been local.

I didn't even expect failure, I plugged the car in, activated the charger with the app. Heard the coil whine and started to walk away as usual then I didn't hear it.

I walked back to the car and as I then realised. The dreaded BCI had come back.

Now I did drive faster to norwich this time as while I set off with just enough miles to get there and back I planned the charge at Lidl not even thinking it wasn't going to work.

Luckily the Lidl has 7KW posts next to the rapid so I plugged into one of them after I waited for the BCI to clear and it charged fine. Can ZE reported the earth resistance of both chargers as the same so unless when rapid charging it requires the earth to be lower I think I could rule it out.

When asking in the owners club again all the blame was on the charger, despite two other members charging there in the last week.

Attempt 4 - Success - PodPoint at Lidl Norwich 27th January 2018
After the 7KW post gave me enough juice to get home comfertbly I decided to try the rapid again before I left. At the same time a tesla pulled up and also plugged in no issues.

Of which my car also started charging. But at a slower speed.

Weather this was because while charging on the 7KW charger the car sat for around half an hour to cool down, or because the tesla plugged in the charger meant that it would only provide less power I'm not sure. But it helps confirm part of the theory, if it was the cable or connector at fault it shouldn't have worked the second time. If it was earth it shouldn't have worked the second time.

Attempt 5 - Success - Geniepoint at Great Yarmouth 28th of January 2018
So the day after I phoned up the company that has recently installed a chargepoint nearby where I live. This is a brand new Geniepoint Rapid charger which was activated on the day I tried it.

I plugged my car in, activated the charger and it was charging. So could it have been the charge point at Lidl?

When looking through CanZE I noticed that the charger was only charging at 30KW, and this was because the batteries were cold and the car was limiting the rate of charge.

Attempt 6 - Failure - Geniepoint at Great Yarmouth 28th of January 2018
After a 25 mile trip to Acle to try a 22KW charge point which worked I decided to detour again via the charger. I only took 1KW when at acle so the batteries had lots of room for charge and were a warm but not hot 15 Degrees. About what I'd expect for a longish journey.

Plugged the car in and activated the charger in the exact same way and the same charger gave me a BCI.

So is it the charger? Seeing how it charged in the morning I couldn't see how it could be. I don't think anyone else had used it as I was only a couple of hours inbetween.

The best I could think is once the batteries had warmed up which in all three cases of failures they would have been, meant that when the car requested 40-43KW the car would fail to charge. I couldn't see how it was the charger as all three with the same issue didn't seem right to me.

Attempt 7 - Failure - Geniepoint at Great Yarmouth 29th of January 2018
I decided now I think I know what the issue is to see if it was replicatable. To replicate I needed to warm the batteries up to around 10-15 degrees to get the car to want to charge at a full 43Kw and I did this by driving 10 miles down a dualcarridgeway at 70MPh. By the time I span around and got to the charger CanZE reported that the batteries were at around 11 Degrees and the max charge rate was around 40KW.

I plugged it in and straight away got the BCI after it tried a few times.

Now I had more of an idea of what was causing the actual issue this helps diagnose it some more and replicate it again.

So what now?

Why does it happen?
So it is a bit unclear as to why it happens. Most members of a Zoe owners club will always say that it is the chargepoint at fault, usually for having a bad ground. (With the same club keep saying I didn't do my research and what did I expect. Maybe for my car to actually charge?)

However in my case I don't believe this is the fault. Using the CanZE App the earth has reported as under 50 ohms, and in the case of the failure at the Lidl on Sunday the 7KW post charged my car which CanZE read as the same resistance. At the same time one of the attempts worked on a Rapid at one time of the day but not another time of the day, the earth can't have gone that much out of tolerance.

So from what I can tell there must be another thing at fault, weather it is the charger or not from the best I can tell it isn't the ground connection.
Furthermore from what I can tell if the ground was at fault, it wouldn't attempt to charge first and instead would BCI before the coil whine as it can check the earth before the charging starts.

So what could it be?
I am at a stage where I do not believe it is the chargers. I am struggling to see how three different chargers, operated by three different companies and three different hardware manufacturers are all faulty.
Without driving to norwich and trying another 3-4 rapids in a day one after the other I can't do much more testing on different units.

I believe it is something to do when the car tries to charge at the full 43KW, weather it ramps up the charge too quickly and creates a surge in the charger, leaks too much power to earth or another fault entirely I'm not sure.

So far Can ZE reports a reasonably high HF leakage of around 150mA but I believe the trip is 300mA. However when querying codes of failures an interesting one was that the neutral sensor had an overcurrent detection of which on a Rapid charger the neutral pin shouldn't be getting any power on it at all.

Its looking most likely if there is a fault it is an issue with the BCB aka Battery Connection Box.

Live Followups

Any updates from now on will be updated to this post as I find out.