Battery failure on my Nexon EV Max & Tata's quick response

I am waiting for the replacement battery to come know. Have been told the car will be returned in 2-3 days max once the battery comes.

BHPian pratikchanana recently shared this with other enthusiasts.

So I had never really taken the battery of my car below 20% since I bought it in June last year. Joined the Nexon EV WhatsApp and telegram groups and got to know it’s generally a good habit to take the car below 10% once very month or in two months. This helps in keeping the battery cell balanced along with charging the car to 100% every time. The charging to 100% was anyways followed as I always plugged in my car at night and it used to get 100% by morning.

But when I decided to take the car battery to 10%, errors started popping up. The limited performance mode which should get activated at 5-10% got activated at 20% when my driver was coming to pick me and I asked him to continue driving. As soon as he reached 16% the car showed a “HV System Fault” alert and car switched to N from D. Luckily he was very near to me when this happened and I went to him, locked the car for 2 mins walked away and unlocked it and the error went away. (tips given by Nexon EV WhatsApp group). The Limp mode however didn’t go away and the car was working with limited performance.

Took the car home, reached at around 14% plugged it to charge, and the HV fault came up again and car refused to charge. Leaving the car for 20-30 mins removed the HV fault error and car started moving but as soon as I plugged the charged the fault came back and the car neither charge nor moved to D after that. Tried this multiple times and finally gave up thinking will contact the service centre in morning.

Had a chat with another telegram group member who faced something similar, and when he tried charging after couple of hours the car started charging. Come next morning I decided heck lets try charging once more before I call the service centre and voila it worked. Charged the call whole day and reached 100% by end of day. (I use the 3.3 KW charger).

Upon researching more got to know HV System fault generally comes after using a fast charger or not charging the car to 100% most times. This wasn't applicable to me so ignored it as one of case and started using the car.

In the next cycle I again decided to take the car to 10% and again limp mode came at 20% and HV fault at 16%. Again this happened when my driver was coming to pick me up in eve, locking the car, walking away, unlocking it, worked again. The car moved to D but in limp mode. Reached home at 14% and again car refused to start charging. Tried starting the car also after walking away but this was also not working and the fault was not going. The car also was not ready to move to D from N.

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After I faced this last time I got to know removing the negative terminal of battery for 10 mins also solves this fault many times, as it does a soft reset to system and clears any software related faults. Tried this and worked, within 20 mins the car started charging this time. Now after getting stuck on road twice my driver was very scared to take the car below 20% again. In the next cycle I asked him to make circles around my home after he again got limp mode at 20%. This time the fault popped up at 17% itself and he parked the car at home immediately. (After the fault comes, the car give you a minute or two the move the car aside safely, after which is moved to N from D).

I asked him to let the car be for sometime but he plugged it in immediately and this time the car started charging without any issues or any kind of reset required. After all these problems I also started to notice that the cars range is falling significantly. Normally I was getting around 200 kms from 100-20% which was down to 125-150 max. Finally after facing the problem thrice, sent the car to service centre at around 35% SOC and asked them to check. They drove the car around and got the limp mode activated at 24% itself and HV system fault at 18%.

This happened on Sunday afternoon and SA confirmed that an external battery vendor will come and diagnose the battery now the next day. All this time I was insisting him to give me a courtesy car. Called him next afternoon and he said the vendor is yet to come and they can not give a courtesy car unless the car is in service centre for over 48 hours. He confirmed in evening that the battery is faulty and will take 8-10 days for replacement to come. This happened fairly quickly to my surprise as I was expecting a much longer wait time to get warranty approval of such a major and costly component. I suggested him hand me my car back and I will use it over 30% If they don't have any courtesy car available. He agreed for the same, asked me to collect the car next morning and charged it overnight to 100% for me.

I am waiting for the replacement battery to come know. Have been told the car will be returned in 2-3 days max once the battery comes. Even after hearing many horror stories of Tata after sales, i have had a very pleasant experience in this almost one year of ownership. However, the battery failing in less than one year is not a great thing to happen but if they can keep up the service and follow the given timelines, it's all acceptable. I feel any issue / problem in an EV is highlighted much more than ICE as its new tech and many people are still not ready to accept it. Both times my driver got stuck on road multiple people told him "battery vali hogi isliye band ho gayi". The stigma against EV cars will take a lot of time to break. Moreover the WhatsApp and telegram groups have become very strong and active and people there are ready to help round the clock as much as they can to any stuck member. In my case also, one of the early and popular member of group Mr. Asheesh really helped in getting this move quickly at the Service Centre.

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