[navinmra]

Originally Posted by ferrarirules

There is a VECU, BMS and IPC update campaign for all Nexon Max users and Nexon Prime with AIO battery packs (manufactured post October 2021).

I got mine updated last week for my Nexon EV Max Dark edition and immediately went on a 500 km drive the same week. Here are my observations post update:

1. Regen curve appears modified and the effect feels different. It appears more adaptive is the best way I can explain it. For instance, when going down slopes at a higher speed, the regen appears low. I guess they are trying to avoid drastic speed drop at higher speeds so the vehicle behind does not get startled. This update allowed me to have a more pleasant drive down ghats with regen on at level 2. Also, regen level 1 appears less aggressive now. I used to drive with regen turned off, but now I can tolerate level 1 in the city. Welcome update I would say.

2. When car is stationary with auto hold turned on and you try to tap the accelerator, auto hold releases as before but creep mode does not kick in as before. The vehicle remains stationary and you have to deliberately push the accelerator to make the vehicle move forward. There is noticeable hesitation and judder, as you would see with an ICE car with a worn out clutch. This seems like a step back.

3. The average energy consumption (AEC) algorithms seem to have been updated. In the past, the numbers on the dashboard used to be always higher than what the app showed. Post update, the gap has narrowed. In fact, in stop and go city traffic with regen level 2, the dashboard shows lower number than the app!

[Sridhar C E]

Originally Posted by ferrarirules

Hi All

There is a VECU, BMS and IPC update campaign for all Nexon Max users and Nexon Prime with AIO battery packs (manufactured post October

My software Update story:
I first heard about the update from a whatsapp group of EV users that I'm a part of.

I called the Tata Motors helpline and asked them if I was eligible for the update and whether they would be getting in touch with a targeted group of customers.

After taking down the details of my car, the person at the other end said that they had no idea about any upgrade and that normally the service centres would call customers directly. However he said he would take me in a conference call with Prerana Motors, my dealer and SC of preference.
I was connected to Mr Daniel Salins GM, service of Prerana.
Mr Daniel said that he would check and get back to me. (I knew Mr Daniel from some earlier interactions).

Later in the day after one reminder, I got a reply-
[10/08, 15:09] Mr DANIELS GM Prerana Motors: Nexon EV Max BMS VECU IPC Software Updation
[10/08, 15:09] Mr DANIELS GM Prerana Motors: There is a soft ware updation. Released for this car . Kindly visit workshop.

On the following Monday I spoke to the workshop and visited them. I was there by 10 AM and the update finally was taken up around noon and it finished by 3.30pm. The car was handed over to me.

As I drove home, I discovered several issues, mostly related to the display on both the instrument panel as well as the infotainment panel. After reaching home I did a comprehensive check and sent Prerana this message-

Hello, My car KA51MU1868 had a software upgrade today at your Kudlu gate workshop. I spoke to Mr Sangamesh about the issues observed after the software upgrade. Also see the attached video.
1. Auto hold, parking brake indicators not showing. However the functions are working, no indicators.
2. Mode change - City, Eco and Sports are also not showing on instrument panel and neither is the voice prompt coming. However mode change happens- it also shows changes in DTE.
3. AIR cabin AQI reading is not showing despite switching on the AC.
4. Instrument panel shows regen selection on screen - asking whether it is to be enabled or not but you cannot select using the steering control button. Regen works with the separate switches near gear knob.
5. Cruise control says selection menu on instrument panel, when you select it says " unable to select cruise control ". Cruise control selection is not possible.
6. Cruise control is not working in the normal way.
All these were working prior to the software update.
Pls get these rectified immediately
You can give me a stand by car till you resolve these issues pl.

I have attached a video

https://youtu.be/SNlCrDSqMcU?si=qTElJelfFjE8O_-W

I also copied Mr Daniel. Within half an hour I received a call from the technician who had updated the software. He promised to come home the next day to rectify the issues failing which he would take the car back to the SC.

The next day he came home and connected his laptop to the OBD port. Despite trying for am hour he couldn't rectify the faults and it was decided to take the car back to the SC the next day.

The following day the car was taken by their driver.
Apparently Tata Motors Pune logged in remotely and reinstalled the update. Apparently the initial update was corrupted.

My car was returned a day later and I find it is working ok as before. I am yet to find out if this update has made any difference in functionality.

This was my first update for the car. I have learnt the following lessons:
1. Don't be in a hurry to get your car updated. Learn from the experience of others.( Unless it involves safety )
2. Prerana was very helpful and responsive to my issues.
3. Tata Motors should tell us what the update is about.

I welcome feed back and the experiences of fellow BHPians.

[Jazzybala]

Has any Punch.ev owner here faced any HV critical issue? I tried to search the forum but attempts so far have shown no such posting.

[idoctor]

Originally Posted by Jazzybala

Has any Punch.ev owner here faced any HV critical issue? I tried to search the forum but attempts so far have shown no such posting.

Not sure if its in the forum, but came across a post on X by a user called Mr Haranmol Singh with X handle as @Haranmol007. He had bought a Punch.EV Adventure LR on 25th April, 2024 and unfortunately he had the HV Critical error in the first 24 hours itself. Attaching the link below.

https://x.com/haranmol007/status/178...9Kuwwj9TMT8nbg

[ferrarirules]

Originally Posted by Jazzybala

Has any Punch.ev owner here faced any HV critical issue? I tried to search the forum but attempts so far have shown no such posting.

Based on our EV WhatsApp and Telegram group reports, it is much lower in Punch.EV and Nexon.EV as compared to Tiago.EV, Nexon Prime, Nexon Max.

[premindia87]

A Punch EV user from WhatsApp group belonging to kerala has confirmed he has got HV critical alert yesterday. It was at 16 percent SOC and he couldn't start the vehicle. Diagnosis revealed it's a traction motor issue. Error was
P3047-09 MCU contactor wield components failure
Status confirmed

[DIY410]

Originally Posted by premindia87

A Punch EV user from WhatsApp group belonging to kerala has confirmed he has got HV critical alert yesterday. It was at 16 percent SOC and he couldn't start the vehicle. Diagnosis revealed it's a traction motor issue. Error was
P3047-09 MCU contactor wield components failure
Status confirmed

Its probably a contactor relay that got welded due to arcing. Basically there will be two contact points inside a relay, there will always be a short arc when the switch or relay closes or opens a circuit. But when the arc is long enough in length and time, the heat generated will be so much that it will cause the contacts to get welded shut, so much so that the magnetic coil inside the relay doesn't have the strength to open it.

[santosh.s]

While sales people tried to follow up with me regarding my Curvv-EV booking, I told them about my apprehension about this HV critical error battery issues being faced by so many Tata EV users. One of the guys claimed that this issue has been addressed with the latest update, though I would take it with bag full of salt. Just thought of sharing this bit of information in this forum.

[mally2]

Yes they are right the new update removes the HV alert but if there is a underlying battery issue that is just masked with this update


Here is the timeline of my issue

01/Sep this day for the first time turtle mode at 16% and HV alert at 14% but car behaving normally. I reached home as I was very close by. I have put for charge and no issues charging fine. I should have been worried but ignored it as a one time anomaly Usually I have done as low as 2% and never faced Hv alert

08/Sep I was able to reproduce the same. This time at 15% it went to turtle mode and at 14% it went to Hv alert. Car continues to drive unless you stop it. Once you stop and if Hv alert is active car won’t turn on. I had to turn off car and wait for sometime and then it turn it on again. Hv alert disappears for some time and car is able to move albeit in turtle mode. Once I reached home at 12% soc car was on Hv alert and it refused to initiate charge. I tried multiple times it would not charge
I waited for some time locked and unlocked and locked again. After that plugged in charger and thankfully charge initiated. I charged the car till 26% soc I stopped charge planning to take to Service center so it can be reproduced there

The SW update Saga


11/Sep So they did some SW update and drained the battery till 6% and no Hv alert was found. At this point I am picking up the car and will test a full range and bring it to 2-3%


Today 18/Sep

The car behaves normally till 31% post that SOC rapidly drops almost 1% every 300 meters. For the record I covered only 19km in the last 31% but 145km from 100-31% @ 123whkm which seems pretty accurate. The problem starts from 30% SOc

Panicking I drove to TASS and reached at 3% SoC last 800 meters dropped SOC from 9% to 3%

No HV alert and turtle mode came to warn this time on. Infact as design properly at 10% turtle
Mode comes but rapid drop of SOC continues from 31%


Car is back to TASS there is clearly a battery issue and the update just masks the HV alert. I find this more alarming. Car will continue to drive normally until 0% but with rapid SOC drop.


So I highly recommend everyone to bring their car to low SOC once a while to check if the battery behaves normally as most issues are found at low SOC. You don’t want to be stuck in a highway at 30% hoping to reach a charger 20km away only to realise you can do only 15km for the last 30% due to a battery fault that now won’t show up due to Hv alert being masked

Please ignore typos due to me typing from a cellphone

[santosh.s]

Originally Posted by mally2

You don’t want to be stuck in a highway at 30% hoping to reach a charger 20km away only to realise you can do only 15km for the last 30% due to a battery fault that now won’t show up due to Hv alert being masked

This just goes to confirm what I had guessed

Originally Posted by santosh.s

Thanks for sharing. Seems like they have just added some kind of an early notification, and probably a chance to pull over, but not really a "fix" as such to avoid it (or at least to reduce the odds)

[mally2]

Originally Posted by santosh.s

This just goes to confirm what I had guessed

It’s both positive and negative. It ensures you can still drive the vehicle and are not stranded. The BMS may be skipping the low voltage cells and excluding them from the available SOC. In any case pathetic implementation. No other EV manufacturers faces this amount of battery issues I suppose.

Coming to think of it. I had opened this thread and the irony of me facing this issue which I dreaded.

[Aceman82]

I got the dreaded HV critical error today. The car had around 32% state of charge (SOC) when the HV Critical error appeared. The vehicle is approximately 1.5 years old and has only been driven for about 5,000 km. It's primarily used for school runs and is the third car in our garage.
The HV critical error suddenly appeared at around 32% SOC, and the vehicle went into limp mode before coming to a full stop. I turned off the car and restarted it; the error went away, but the car was operating with reduced performance. I drove it to my home garage and parked it, at which point the HV alert appeared once more.




I tried to charge the car, but the alert keeps popping up, and it refuses to charge. I'll need to call Roadside Assistance (RSA) tomorrow and request a tow to the service center if it fails to charge in the morning as well.

If a vehicle with only 5,000 km on it experiences battery issues, what are the chances of reliability in a high-mileage vehicle? Who would want to own such a car outside of warranty?

This is my third car in the garage (I have two other cars and two two-wheelers), so I don't mind it being in the service center for extended periods. Saying that, My 8 year old XUV500 would had less service centre visits than the 1.5 year old Tiago EV .

This is quickly turning out to be a garage queen where one needs infinite money and patience to keep a EV car from Tata.

Will keep this thread posted on updates to the Battery issue.

[santosh.s]

I know this is quite optimistic or wishful thinking, but still. I have been following Currv and Windsor EVs closely since I am in the market for a mid-size EV. I am wondering whether cylindrical versus prismatic cells are going to have any impact on this issue. Curvv is using prismatic cells in it's bigger battery pack and Windsor is also using the same type of cells from the same OEM supplier. Whereas, I believe all previous Tata cars known to be marred by the issue use cylindrical cells.

Can the experts or those who have any insights into it comment whether this move to prismatic cells and/or MG's involvement by sharing apparently the same component have any changes of resolving the issue?

[DIY410]

Originally Posted by santosh.s

I know this is quite optimistic or wishful thinking, but still. I have been following Currv and Windsor EVs closely since I am in the market for a mid-size EV. I am wondering whether cylindrical versus prismatic cells are going to have any impact on this issue. Curvv is using prismatic cells in it's bigger battery pack and Windsor is also using the same type of cells from the same OEM supplier. Whereas, I believe all previous Tata cars known to be marred by the issue use cylindrical cells.

The flaw in Tata implementation is more to do with their BMS. The main advantage of prismatic cells is the Ah rating, Tata choose the cylindrical cell because of its small size, they could squeeze those cells in every nook and corner. But its Ah rating was only 15 Ah, which meant that Tata needed a whole bunch of cells to be in parallel and that will result in some cells being unevenly charged or discharged.
Tesla also uses cylindrical cells, Model S used to have cells of just around 3 Ah but the difference is those where NCA cells, which meant that Tesla could charge them below the peak voltage of 4.2v. This strategy is also done by cordless tool makers, where they charge the cells to just 4v and in situation where some cells are defective and go slightly up in voltage, they will still be below 4.2V max voltage. Also because of linear voltage curve of NMC/NCA vs flat curve of the LFP, the BMS is very easy to design.

Now with prismatic LFP they don't have that problem because those cells can be 100+ Ah, so they will not be connected in parallel. So when that defective cell hits 3.6V, the BMS will start throttling the current and if the voltage still continues to rise up, it would bleed it of by using a resistor or take the energy from it and dump it to the cell which has the lowest voltage. But when the cells are connected in parallel, the BMS does it to the entire row of cells meaning those defective cells where never going to be balanced individually.

A defective cells or a cell that has lost its capacity will be the first to hit peak voltage during charging and also be the first to hit the low voltage cut off during discharging. So it effects the entire row of cells in parallel.

[anshumandun]

I had posted this in the Tiago EV review forum a few days back; thought of updating here also. My car's HV battery has been replaced to fix the HV critical error. The car is running fine now. The car is 1.5 years old and done 45000 kms.

The service person told me that Tata has expedited the warranty replacement processfor HV critical issues.

I saw another post on the review forum of the complete battery being replaced for another person. His/her car has done 14,000 kms.

Is there any way to change my vote on this thread?