Ultra Capacitor Issue

Hi all

Firstly thank you for a truly great forum. I am UK based, I have a generation 1 used Leaf, 2012 registration with 12,000 miles and its a superb car. I have had the car 2 months now and for the last 5 weeks the car has been back with the supplying dealer (not Nissan) with a rapid charger fault (I.e. it will not synchronise and accept a rapid charge even though it will home charge on the slower port). From day one of ownership the rapid charger has never worked (I did not know this as the time of purchase). I have had to limit my use to local and commuting use only.

I advised the supplying dealer of the fault at week 3 of ownership once I was up to speed on how to charge it. I tried 5 different rapid chargers local to me to ensure it was not me. The last one was at a local Nissan main dealer who confirmed the car was faulty. I called my supplying dealer who duly booked the car in for assessment.

Anyway fast forward 5 weeks to today, the supplying dealer had to give the car to Nissan almost 2 weeks ago to diagnose the fault. After 10 days Nissan stated the ultra capacitor is faulty and that my car needs a new charger. Nissan confirmed the car fault was not a warranty repair so my supplying dealer is making a claim on the extended warranty they gave me with the sale of the car.

My question, does this fault sound consistent with not being able to rapid charge? The Nissan dealer said they struggled for days to diagnose the fault. I'm at a total loss with it and its really starting to test my patience waiting for the repair to actually happen. I have repeatedly asked for a full refund so I can go and buy another Leaf.

How much is an ultra capacitor to buy for the Leaf? I'm trying to work out if the car is a viable repair as I am super keen for that refund.

Thank you.

In the USA, the entire EV powertrain is under factory warranty for 5 years or 60,000 miles, but I don't know if you have the same warranty. The only ultra capacitor I know of on the Leaf is for the power brake/ABS system operating on 12 volts and would have nothing to do with charging. The brake system will set several DTC error codes if the 12-volt battery gets weak. The onboard charger is certainly covered by the EV powertrain warranty and I think the onboard charger controls the fast charging process, but am not positive.

Gerry

Not much to add, but to say the Ultra Capacitor is hooked to the 12 volts, and from a picture
of the inside, I would guess has a boost circuit, which means the right kind of failure could send
garbage on the 12 volts that is hard to see and diagnose. So while not expected, it could effect
the fast charging. Also a while back I was looking at the warranty(US), and they carefully mentioned
twice that the charger is a part of the drive train, which is under the 5 year coverage. If the
Ultra Capacitor unit (if I remember correctly, has 24 Ultra(Super) Capacitors inside) is not under
warranty, then you get to keep it, and someone could find what was wrong with it.

tonyp said:

After 10 days Nissan stated the ultra capacitor is faulty and that my car needs a new charger. Nissan confirmed the car fault was not a warranty repair so my supplying dealer is making a claim on the extended warranty they gave me with the sale of the car.

My question, does this fault sound consistent with not being able to rapid charge?

Click to expand...

Not in the least. As mentioned, the ultracapacitor is simply there to hold up the 12V to the braking system long enough to stop the car in case of a crash or system failure. That's it. The ultracapacitor can be completely discharged and the only function lost is the brakes.

It sounds to me like the dealer damaged the ultracacitor while trying to diagnose the issue with negotiation of a quick charge. Note that the ultracapacitor is located under the hump in the back next to the on-board charger. While the OBC should not be involved with quick charging, perhaps they were disconnecting it to try to ensure it was not causing the problem.

FWIW, I recall one member here had an early-model LEAF which would not quick-charge and it turned out to be a pin in a connector which had gotten bent during assembly at the factory. I wonder if the same issue might be plaguing your LEAF.

Thank you all for your replies. I had a long conversation today with Nissan today about the fault and claiming process. Upshot is the car fault (be it the ultra capacitor or the charging system) is not covered under OEM warranty for my car in the UK (the car is not 4 years old). They are claiming on my supplying dealers warranty insurance. They confirmed the costs but not the specific parts to me, they were £1266.91 for parts, £300 for labour and all plus the VAT. Its a total of £1880.29 to fix the car.

The insurance assessor is coming to view in the next 2 days and a decision will be made if its going to be fixed! Either way it will not cost me anything. Finally to add the part or parts they need are not in the UK and are going to take once ordered 5 to 10 days to arrive. Nissan did say expect the car to be repaired within 3 weeks worst case from today. That's one hell of a repair time.

I will let you know once I get the car back or if they indeed give me the refund I have been asking for, for selling me a faulty car from day one.

Quick update. Its is the charger and now both dealers are "discussing" who pays for it. I have just read my warranty booklet as has been pointed out here, it is covered under Nissan warranty. I'm going to show them the booklet tomorrow to show its well within the 5 year OEM warranty. Once Nissan accepts this fact they should then order me the charger and fit it.

Fun and games for sure.

I don't understand references to "the charger" in this context. It's my understanding that the DC Quick-charging does not use the vehicle's onboard charger.

Nubo said:

I don't understand references to "the charger" in this context. It's my understanding that the DC Quick-charging does not use the vehicle's onboard charger.

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Agreed, but since there are two ways to charge the battery, it makes sense that a fault in the OBC might cause problems with quick charging. At the very least, there needs to be some sort of interlock in place to prevent both chargers from being active at the same time. Perhaps there something wrong in this regard.

In the 2011-2012 vehicles, there is a daughter card inside the on board charger that controls the DC quick charge process (control lines, CAN link to the CHAdeMO unit, communication with the BMS, etc).

So from a power perspective the OBC isn't involved but from a control standpoint, it is.

JeremyW said:

In the 2011-2012 vehicles, there is a daughter card inside the on board charger that controls the DC quick charge process (control lines, CAN link to the CHAdeMO unit, communication with the BMS, etc).

So from a power perspective the OBC isn't involved but from a control standpoint, it is.

Click to expand...

Thanks for clearing that up!

Well the fight to take repair cost ownership continues! I have had to submit all the cars servicing/warranty information today as I did not give them the booklet when I dropped the car off. The Nissan dealer has applied to Nissan HQ for the warranty repair so fingers crossed the warranty information I have saying its covered is honoured. Then its a nice 2 weeks wait for the part to arrive and fitted. Estimated car repair 3 weeks from now, I'm hopeful its less than 2 but I'm so disillusioned I doubt it.

Thanks for explaining why it may be the OBC stopping the rapid charge process from starting. Its all new to me and I know my way around an ICE car!

JeremyW said:

In the 2011-2012 vehicles, there is a daughter card inside the on board charger that controls the DC quick charge process (control lines, CAN link to the CHAdeMO unit, communication with the BMS, etc).

So from a power perspective the OBC isn't involved but from a control standpoint, it is.

Click to expand...

Ah, makes sense. Thanks!

Good news Nissan HQ agreed to repair my car under the 5 year warranty (as I suspect we all knew this is what had to happen). At long last the part is on order so I am happy knowing its only going to be about 2 weeks before it arrives. Lets hope this fixes the issue!

This is truly a great forum. Thanks for the info !

Well final update, the car was finally fixed today 11th May 2016. Its had a new on board charger fitted. I took it to the first rapid charger on my way home (the dealer was 50 miles away) and gave it 15 minutes on the charger. It worked a treat so I'm now a happy Leaf owner again. All in the car was away for 6 weeks exactly. Peugeot had the car and booked it into Nissan once they confirmed they could not fix it! Nissan had the car for 4 weeks, it took them 10 days to identify the fault, 4 days to agree to pay for it and 2 weeks for the part to arrive and be fitted.

Overall I'm glad I got it fixed under warranty but its been a massive hassle. I'm not to impressed with either dealers but ultimately its been fixed and I am back with it. Its had a wash and valet and looks like new again.