Early models of the Renault ZOE would quite often encounter problems with charging at public charging points and would show a message saying “Battery Charging Impossible” (BCI). The ZOE electronics were updated at about the time the new R240 version of the ZOE entered production to fix this issue – however, I’ve learned it can still happen with a new ZOE so let’s look at it in detail.
I had one of the early ZOE’s so i’m experienced with this error. The first thing to note is that in most cases it does not indicate that there is anything wrong with the car. The message simply means “Battery Charging Unsuccessful” and refers to the last charge attempted whereas the wording – perhaps a poor translation from the French – implies something more serious.
When a charge point (CP) is connected to the ZOE a communication takes place between the car and CP to agree a rate of charge. Also the ZOE checks the earth connection of the CP to make sure that it is securely earthed for safety reasons. A BCI error generally indicates that the ZOE found that the CP is not sufficiently well earthed to be safe and so it refuses to charge.
While this might seem to be obviously an appropriate response to a potentially dangerous situation the simple fact is that other electric cars are not so ‘fussy’ as the ZOE and quite often will charge at a CP that the ZOE has a problem with. Worse, the earth connection will vary with outside factors (e.g. weather and dampness of the ground) so that a ZOE can be happy with a CP one day but refuse to use it another day. While it might seem reassuring that the ZOE errs on the side of caution and refuses to charge with a CP that it can’t guarantee to be safe, the result is frustration for the driver when the car needs a charge.
The issue of a BCI from poor CP earthing is well documented. However, there may be another issue that causes BCI’s occasionally. There is a lot of circumstantial evidence that the ZOE charges more reliably – particularly with DBT rapid chargers – if the weight of the cable is taken off the connector when the connector is inserted into the car. It’s possible the cause is that the upper pins are not fully connecting during insertion. I suggest, therefore, a BCI may also be caused occasionally by the connector being pulled down by the weight of the cable when initiating the charge. This may be exacerbated if the spare cable is ‘tidily’ pushed under the nose of the car.
Since BCI in its simplest form is just a message to let the driver know that the last charge attempted didn’t succeed the obvious solution is just to try charging again. Unfortunately the BCI seems to be a ‘sticky’ error, in other words once it has happened it more likely to happen on subsequent tries – until a charge succeeds at which point it is completely wiped from the system. Therefore it is not unknown for follow on attempts to charge to produce a BCI even on a CP (e.g. at home) that has previously been fine.
In most cases, however, the BCI ‘stickiness’ will time out. Anecdotally, most people find that it only lasts 10-15 minutes, some people have found it lasts about an hour, and occasionally it can last until the car has sat overnight. In an ideal situation it is best to let the error time out and then try charging again – but it is not unknown for an attempt to charge while the error is still there to succeed, and for it to be cleared, before it has timed out.
Occasionally all attempts to clear a BCI fail and this indicates a hardware fault – it is, however, very unusual. The first thing to check would be the charging cable. If that is fine, then the car needs to be taken to a dealer to be checked.
So, let’s add that all together into a useful procedure.
What to do if you get a Battery Charging Impossible (BCI) message
- Don’t panic! In most cases it’s fixable by the driver and doesn’t indicate a long-term issue.
- Try charging at least 3 times before giving up:
- Support the connector where it goes into the car to make sure the upper pins are fully connecting. Listen for a successful latching of the connector into the car (multiple latching sounds may indicate a problem).
- If you’re at a location with multiple charge points, try a different one each time if possible.
- If that fails, shut down, lock up the car and leave it for 15 minutes, then repeat from 2.
- If that fails, shut down, lock up the car and leave it for at least 1 hour, then repeat from 2. However, if time is tight go to the next step.
- Drive to a different type of charge point and repeat from 2. If possible, it’s usually best to use your home CP as that’s the most reliable and forgiving type. Otherwise, if at a street 7kW charge point try a rapid charge point, or vice versa. Repeat from 2.
- If that fails (and that should be very rare) then it could be the cable. Borrow an alternative Type 2 cable and repeat from 2.
- If that fails then it looks like there may be a problem with the car – call your dealer and arrange for the car to be checked.
Source: Fuel Included Blog