[prateekchanana]

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.

HV Error

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.

[ferrarirules]

Originally Posted by prateekchanana

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. .

It is good to hear that Tata has provided a fast resolution to your issue. Yes, battery pack change is a big thing but it is better than they trying to repair the battery. Also good on their part that they gave you the car back, companies like VW/Skoda like to keep the car if there is a warranty claim.

[prateekchanana]

Originally Posted by ferrarirules

It is good to hear that Tata has provided a fast resolution to your issue. Yes, battery pack change is a big thing but it is better than they trying to repair the battery. Also good on their part that they gave you the car back, companies like VW/Skoda like to keep the car if there is a warranty claim.

Oh I had a terrible experience with VW while trying to get a simple head unit replaced. My 6 months old polo had some lines coming on its display, first I visited them to complain about it, they made a video of issue and told me will update. 5 days later called me that the replacement is approved, I need to come to get it swapped. So far so good, reached the service centre and they told me they now have to send the head unit physically to their plant and only then replacement will be shipped. The process will take 8-10 days. I begged them not to send me back with a car without the head unit or install a temporary one. My daily commute that time was 40 kms taking 2 hours. But they didn’t agree and drove a 6 months old car for 2 full weeks despite mailing VW / following up regularly with the dealership.

Tatas approach on this issue on the other hand is very customer centric. If they couldn’t arrange a courtesy car, handed me over mine with a fair warning of using it above 25-30% SOC. Infact I am much more comfortable using my car on my terrible daily route where regularly new scratches keep happening.

Repairing the battery will take atelast 25-30 days if they start doing that as of now. The battery will be removed, making the car unusable, sent to their manufacturing facility. Disassembled and then the faulty cells will be examined and replaced. Assembling it back and then sending back to customer will make it a very poor experience for customers and very long down times.

[GTO]

Thanks for sharing, Prateek! Moving your post out to a new thread. A new thread means 100X the views & 100X the visibility in search engines, including Google. Will add to homepage today .

@ BHPians, if you should spot any good post in an existing thread that deserves its own new thread, please report the post and we'll move it out for greater visibility.

Thank you!

[Nanolover]

This is the exact sort of scenario that happened to me in the tigor EV and the battery was replaced. Have never gone below 25 % charge because frankly I am scared with my past experiences and don't want to replicate this in rush hour traffic.

[ferrarirules]

Originally Posted by Nanolover

This is the exact sort of scenario that happened to me in the tigor EV and the battery was replaced. Have never gone below 25 % charge because frankly I am scared with my past experiences and don't want to replicate this in rush hour traffic.

Just a word of advise, please do below 20% to 100% charge as least once a month. This is good for maintaining battery health

[prateekchanana]

Originally Posted by ferrarirules

Just a word of advise, please do below 20% to 100% charge as least once a month. This is good for maintaining battery health

Exactly, if I wouldn’t have tried taking the car to 10%, would have never got to know that the battery has any fault.

[androdev]

VW helped us get a diploma in ICE car internal workings. TATA is going to make us learn how EV cars work (or not work).

[prateekchanana]

Originally Posted by androdev

VW helped us get a diploma in ICE car internal workings. TATA is going to make us learn how EV cars work (or not work).

Oh VW taught me VCDS too which I found very cool. Using your laptop to change / tweak car features in 2015 was very cool for me

TATA has taught me current EVs are more of a windows computer than a car. Most problems solve themselves after a force reboot / restart.

[venki.krishnan]

Originally Posted by prateekchanana

So I had never really taken the battery of my car below 20%

Prateek, What is the cost of battery and did the warranty cover the cost?

[gururajrv]

I do not think it's safe for you or for your family or even the driver to operate the car in this condition. Battery isn't containing the charge leading to leakage of energy which indicates battery also to be heating up significantly, which is the case with phones as well. When phone discharges battery rapidly, you'll notice heating. I believe the concept applies here as well with cars. I am not an expert but just a normal observation.

Slightly OT:
Another thing is, FNGs will be a thing of the past in the coming decade with EVs taking over ICs, these FNGs will have a tough time whilst the OEM dealers will enjoy centralized focus in terms of customers having no other options in the market other than visiting dealers for servicing or repairs!

[prateekchanana]

Originally Posted by venki.krishnan

Prateek, What is the cost of battery and did the warranty cover the cost?

It was covered in warranty as the battery pack carries a 8 year / 160000 KM warranty. I think it costs around 7 lacs out of warranty as someone posted it for nexon prime. May be more for max. But if you have a manufacturing fault I don’t think it will not show up for 8 years and suddenly show up one day after that.

Originally Posted by gururajrv

I do not think it's safe for you or for your family or even the driver to operate the car in this condition. Battery isn't containing the charge leading to leakage of energy which indicates battery also to be heating up significantly, which is the case with phones as well. When phone discharges battery rapidly, you'll notice heating. I believe the concept applies here as well with cars. I am not an expert but just a normal observation.

I don’t think it is write to compare a car battery with mobile phone. Mobile phone batteries are temperature cooled, a hot phone will only cool down when you stop using it or the temperature around it falls. Nexon battery on the other hand is liquid cooled and the coolant is continuously trying to maintain its temperature, and if that doesn’t work, the car turns on its fan / AC automatically to cool down the battery if it detects over heating (happens in every charging cycle during summers as well). Also when on the go and if the battery is heating, the car automatically prefers to use the AC to cool down the battery over the cabin. Many more expensive cars come with a separate AC compressor for battery for this reason.

Also I have personally used the car 4-5 times after this issue and the problem isn’t happening above 20% and same happened with showroom. So in all probability only some lower part of cells of my battery are damaged and the upper part are working alright. If cell replacement was an easy to do - service centre lever job, Tata would’ve done that instead of replacing the entire battery pack.

[userAditya]

Originally Posted by prateekchanana

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.


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".

I too have heard 'Fast Charging' outside is causing HV alert. Here in Pune when we were enquiring about Tiago EV a dealer associate told me that fast charging should be avoided if possible. And to add to that he told us a weird thing, well won't be weird for some tho. He said : 'you have to charge the vehicle only when it comes down below 25-20%. We can obtain logs of how the battery is charged/maintained by a user. If you follow that pattern the battery health will remain good.' I thought this was too much of a stringent task to do this all. Then again after 2 months we went, another associate over there when we told him regarding the battery charging pattern we had heard from another associate over there, he laughed it off, saying 'Dont worry too much! You can charge whenever you want just do a full charge at home once in a while from 10-100'. At times I feel the service associates over there are still not fully literate regarding EVs. They need to be given a bit of training, infact I feel there should be a dedicated showroom and service centers for EVs.


About service, I think Tata's service is good in big cities. Be it Delhi, Pune, Mumbai, I have heard nothing but good stories. Feels good to know your problem was resolved, that is what expected in general.


People are very quick to judge in our country. They won't say anything when an ICE car face issues like burning or stalling in the middle of a street. Ignore the ruckus. That said times are changing, I am seeing more and more EVs on streets now and the count will only increase.

[DarthVeda]

I too have heard 'Fast Charging' outside is causing HV alert.

There are many reasons for that error to popup. Think of it as an Generic try/catch clause.

One of the reason why some get HV fault after fast charging is that the current at cut-off point, which is when the car requests less AMPS than it's peak capability (usually 90%) but the charger is too slow to respond and it sends higher AMPS, this causes the car to flag this as an error and pop it up. This has happened on 30kw star chargers and few of the chargers installed by BPCL. Most of these errors are safe guards and can be cleared using an OBD2 adapter and app.

Coming to the error that OP faced, this is when something is wrong with the battery cell that they can supply required Amps at lower charge, even if one cell misbehaves the BMS would flag this. There could be umpteen reasons for this to happen, one of the common one is battery calibration, which could be done by taking battery to low % and charging all the way to 100%.

IMO, the manufacturers should detail to the user the error and have better diagnostic than the current BOOLEAN logic.

[shyampsunder]

Originally Posted by gururajrv

Slightly OT:
Another thing is, FNGs will be a thing of the past in the coming decade with EVs taking over ICs, these FNGs will have a tough time whilst the OEM dealers will enjoy centralized focus in terms of customers having no other options in the market other than visiting dealers for servicing or repairs!

It's not going to affect FNGs alone. With lesser moving parts and lesser things to service and longer service intervals, service revenues are going to take a hit either way. That's one of the main reasons for legacy autos to drag their feet on adopting EVs.