Is There an 80% Limit on Rapid Chargers?

Over the past week or so there has been a bit of a scare… some Nissan Leaf drivers started reporting on forums and Twitter that they couldn’t charge past 80%. Several people reported this and at different charging locations and so I started to get worried…

  • Was I also going to also be restricted to 80% when charging at a Nissan or Ecotricity rapid charger?
  • Was this a new policy of Nissan/Ecotricity?
  • Was it a genuine mistake and that perhaps the chargers had been set up incorrectly?
  • Was it a misunderstanding by the drivers about how to use the chargers?
  • Was there some other as yet unknown cause?

There was a lot of speculation and advice offered which didn’t help and from some of the comments I could see that many EV drivers really didn’t know how to use these CHAdeMO rapid chargers. Clearly things were not being clarified and so I decided to try to find out more for myself and to try to determine what was going on here.

The only sensible option for me to do that was to visit some of the locations myself and see if I could replicate the issue in my Nissan Leaf and so I decided to drive from my home in Saltash, Cornwall to Waterlooville, Hampshire (180 miles) which was one of the locations reported to be restricting charging to 80%. I would have to stay overnight but a quick search on line secured me a cheap B&B and off I went.

I shall talk about the trip on a separate post.

I arranged to meet Grant Thomas (http://twitter.com/GrantAThomas) at the dealer so I could see what he had done to make him think that it was restricting charge level to 80%. A couple of things were clear straight away:

  1. He had left the car powered on when he tried to charge past 80% and this gave an error on the charger.

    Make sure that the power on the car is OFF before starting to charge.

  2. He was trying to select a charge level. It is possible to select a charge level but this is completely optional. On the older chargers you could select up to 100% but on those installed more recently this is restricted to 80%. This may be one of the sources of confusion because although on the new chargers you cannot select a value greater than 80% the charger will still charge to 100% using the “standard charge” option and not selecting any level.

    Do not select a level or time. Just ignore those options and charge using the “Standard Charge” option or just hit “Start Charge Session” without selecting anyting else. “Standard Charge” is the default. This will then stop the charge at 80% if your car was already charged under 50%, or it will go to 100% if the car charge level was over 50%.

    So, if your charge stops at 80% just restart the charge using the “Start Charge Session” and it will then charge to 100%. Easy.

To charge over 80% on newer chargers don’t use the level selection.
Just hit start and double charge if needed

Of course you can choose to use the preset charge level if you wish but with chargers that were installed recently you will not be able to select a value greater than 80% and you will have to double charge using the standard charge option.

Both Grant and I charged our Mk 1 Leafs to 100% at Waterlooville without a problem using the double charge technique.

Grant videoed this:

I decided that as I was just 35 miles from the new chargers at Fleet services that I would pop up there and try them out too. They are no different in any way to the one at Waterlooville. The double charge technique worked fine and I charged to well over the 90% on each.

Clearly this is not a conclusive test. I have only tried 3 chargers and I have only used my car (Mk 1 Leaf with latest firmware). However, from the descriptions of the forum posts I am pretty sure that this whole thing is just a misunderstanding. I suspect that when some drivers encountered one of the newer chargers they found it would no longer allow them to select 100% and not knowing about the double charge technique they assumed that the charger would not let them charge past 80%.

I don’t think those drivers can be blamed in any way for this misunderstanding. My personal opinion is that the charging instructions should be much clearer and more accessible. They are on the web but why should a new EV owner have to search the web to find out how to charge? Surely these instructions should be on the charger in some way, either by a help system using the chargers LCD screen or posted in some other way. I think it is a heads-up to Nissan and Ecotricity really. They are doing such a fantastic job getting these chargers installed it would be a shame if people lost confidence in them just because the instructions are not clear or not accessible.

Grant has posted his version of how to charge to 100% here.

I have done over 200 rapid charges in my 2.5 yrs of Leaf ownership and I have never set a charge value. I always just use the standard charge and double charge if I want to go higher than 80%. That is probably why I didn’t notice the change on the newer chargers.

Summing up then:

  • It looks highly likely to me that all of the Nissan and Ecotricity rapid chargers will allow charging to 100% by using the double charge technique
  • Older chargers will still allow selection of 100% but newer chargers will only allow selection to 80% HOWEVER, if you want to charge to over 80% on one of these newer chargers do not use the level selection and just use a standard charge and the double charge technique.
  • The chargers seems to over-read by about 10% on Mk1 Leafs but reports suggest it is more accurate on the latest Leaf version.
  • I tested just Waterlooville and Fleet. They are the only ones I can speak for with any authority. If you believe that there is a 80% restriction somewhere else and you have tried the double charge technique and it did not work then please comment here or get word to me. I will try to personally test it out if at all possible.
  • I used my own car which is a Mk1 Leaf with the latest firmware. There is a small chance that the charger may operate differently with other cars, or even with later versions of the Leaf or with other firmware versions. Again, if you think you have a problem that the double charge technique doesn’t solve then please let us know.

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