[TusharK]

Last week, a video of a Nexon EV catching fire in Pune surfaced online, prompting Tata Motors to conduct an investigation. The carmaker has now published its findings.



Tata Motors claims that the fire was a result of a repair job undertaken at an unauthorised workshop. It is said that an improper headlamp repair led to a short circuit, which started the fire.

Official statement:

“We understand that this vehicle recently underwent repairs, wherein the left headlamps were replaced at an unauthorised workshop. Over an extended period, this led to a short and trapped heat. The fitment and repair process, at the unauthorised workshop, had shortcomings, which caused an electrical malfunction in the headlamp area leading to the thermal incident. The affected area is concentrated only in the zone of repairs carried out. We remain engaged with the customer to offer all the support needed."

This is not the first time that an incident involving a Nexon EV has come to light. A similar incident was reported in Mumbai in June last year.

Link to Team-BHP News

[chandu]

Does this not sound like a bogus analysis?
A well designed electrical system will have a fail safe fuse or circuit breaker that should protect the system from a malfunctioning node that has failed with a short circuit.
Even if a head lamp short circuited and caused an excess current flow leading to over heating and fire, a correctly rated fuse should have opened up and stopped the flow of current into the affected node.

[padmrajravi]

Originally Posted by chandu

Does this not sound like a bogus analysis?
A well designed electrical system will have a fail safe fuse or circuit breaker that should protect the system from a malfunctioning node that has failed with a short circuit.
Even if a head lamp short circuited and caused an excess current flow leading to over heating and fire, a correctly rated fuse should have opened up and stopped the flow of current into the affected node.

If the vehicle underwent repair at an unauthorized service center, none of these arguments hold good. The manufacturer can always argue that even the failsafe mechanisms were altered. Most workshops that replace headlamps with high-power ones, mess with the fuses too.

[Venkatesh]

Tata Motors statement in recent Nexon EV fire.

[WhiteSierra]

Originally Posted by padmrajravi

If the vehicle underwent repair at an unauthorized service center, none of these arguments hold good. The manufacturer can always argue that even the failsafe mechanisms were altered. Most workshops that replace headlamps with high-power ones, mess with the fuses too.

Over the years, I've had headlights repaired, changed the bulbs to higher powered halogens, xenons, LEDs, with additional relays, without relays on various cars, that too mostly TATA cars. Not just this, I did the same with fog lights, bar lights, auxiliary fog lights and much more. I never had any issue regarding these modifications, not even a blown fuse, all work done by independent garages, car decors and even DIY.

Now I am curious about this Nexon EV fire accident as both ICE cars and EV cars power headlights through same 12V DC car battery but not with the battery pack which actually powers the motor. So am I missing something here or as someone as said above, could this be a bogus analysis? It would be nice if TATA comes up with some more in-depth analysis and report regarding this fire accident.

[Jeroen]

Shorts don’t necessarily blow a fuse. Especially head light fuses are rated relatively high. At least 10-15Amp is not unusual.

If a poor connection doesn’t cause a full short that blows the respective fuse there are still a lot of Amps going through poorly done wiring. The wiring will heat up and causes parts to catch fire.

So I would say a highly credible explanation from a technical point of view at least.

Jeroen

[dsuman]

It's really difficult to validate if the findings are accurate or bogus. We all know if an unauthorized work is done then its open to speculation irrespective of the quality of the work done. Tata motors can simply wash off its hands because they dont know how cleanly the unauthorized work is done.

Tough to take a side here.

[kosjam]

If TATA releases a statement with its findings, its taken with suspicion and misgivings, that the manufacturer is trying to evade an issue.

If TATA keeps quiet about the whole issue, then its taken with suspicion and misgivings, that the manufacturer knows something is wrong and is trying to evade an issue.

The same happens if the government agency/RTO/etc issues statements either way.

Fact of the matter remains that looking at the pictures of the fire damaged vehicle, the fire was nowhere near the batteries, so probability of it being an EV related issue is low.

Those who say that we have done modifications without a fire happening, need to understand that, of the hazards that are present, very few are converted into actual fires. It just happens to be an EV where this has happened, and as we know, any fire involving an EV is news worthy...

[chandu]

Originally Posted by Jeroen

Shorts don’t necessarily blow a fuse. Especially head light fuses are rated relatively high. At least 10-15Amp is not unusual.

If a poor connection doesn’t cause a full short that blows the respective fuse there are still a lot of Amps going through poorly done wiring. The wiring will heat up and causes parts to catch fire.

So I would say a highly credible explanation from a technical point of view at least.

Jeroen

A short in an automotive circuit can easily result in a current of 100A or more drawn from the battery, no fuse should be rated so high. Typically these fuse ratings are carefully calculated so that any unnecessary current load should blow the fuse.
We make parts for automotive electrical systems and there is no way a failure analysis like this would ever be accepted by an OEM.

[Shreyans_Jain]

Originally Posted by chandu

A short in an automotive circuit can easily result in a current of 100A or more drawn from the battery, no fuse should be rated so high. Typically these fuse ratings are carefully calculated so that any unnecessary current load should blow the fuse.
We make parts for automotive electrical systems and there is no way a failure analysis like this would ever be accepted by an OEM.

Nexon’s 12v electrical system works of a standard 35amp battery, if I am recalling correctly. So, shouldn’t the max current of the system be limited to 35A?

Originally Posted by padmrajravi

If the vehicle underwent repair at an unauthorized service center, none of these arguments hold good. The manufacturer can always argue that even the failsafe mechanisms were altered. Most workshops that replace headlamps with high-power ones, mess with the fuses too.

It is one thing for the manufacturer to give an explanation that washes its hands off a liability. Building trust in its products and allaying customers’ fears is something else entirely and far more important.

I am not suggesting that Tata Motors have given a bogus or false explanation. But they certainly could have gone in more detail and explained their findings openly. This is not a case where you want to lawyer up or hide behind fineprint. Tata has learnt the hard way, with the Nano fire instances, what happens when customer fears are not addressed adequately.

[chandu]

Originally Posted by Shreyans_Jain

Nexon’s 12v electrical system works of a standard 35amp battery, if I am recalling correctly. So, shouldn’t the max current of the system be limited to 35A?

The 35AH rating means that the battery can supply 35Amps for 1 hr at 12V. It does not mean that battery is limited to 35 Amps. In a short circuit condition, the current is only limited by the internal resistance of the battery.
There are lots of videos on youtube that show what happens when an automotive battery is short circuited on purpose.

[ferrarirules]

The person whose Vehicle was damaged in the fire was reached out by someone in the EV community. This is the feedback that was received (I have put it as it was put in another group discussion)-

"Finally I had a word with him again as I wanted to check with him the status of the vehicle so to help him out ..
During discussion mentioned that his car had an accident of the front left side in January 2023 .. and his insurance company got the work done from a centre which is not Tata Authorised as cashless from the insurance provider was not available at any Tata Motors service centre..

Lights and all were replaced along with the wiring. He did not really check the genuinity of the bulbs or wires or if even they were replaced or just repaired. In all this Tata Service Centers were not involved and nor do they provide original spares to any of such agencies. "

This should put to rest all the speculation on what fuse should have blown or shouldn't have blown. It was an accident repair done outside of TML workshop and it required changing/repairing of wires. Also as per the same group discussion, the person was provided a loaner car by TATA despite the unauthorized work and they were assisting him.

Finally a lot of other non EV cars catch fire in this country but no manufacturer releases an press statement about the fire. They don't even do any investigation into the reason of the fire.

[svsantosh]

Having briefly worked in an offroad special (AFM) garage in Dubai for a few years I can honestly vouch that a under-engineered AFM electrical job can do the harm in OP pictures. The amount of safety my electrical in-charge used to take to wire AFM light bars and LED lights was insane and only the fitting cost used to cost an arm and a leg (if done as per AFM brands installation Specs). We have spent days to diagnose a CEL/ECU error because of a minor earth leak in some unknown part of the car. Unrelated wires used to melt, entire OEM harness will become super warm (just before melting) because of a badly done accessory like wiring of compressors, LED light, etc. PS - Work done was mainly on Raptors, TRXs, Few FJ Cruisers & Patrols.

The above explanation aside, if you see closely only the engine bay or the 'exide' battery area of the Nexon looks burnt. Isnt the Lithium battery beneath the car? That system has been isolated safe in such a major fire - Kudos to Tata for that. A 100-200Kw battery fire wouldnt be so minor.

[IshaanIan]

Why did the left side headlamps require replacement in the first place? I have seen so many new Tata vehicles (under 5 years old) with drls or lights not working on one side and wondered what causes such basic things to fail on these cars.

[Bluengel180]

Originally Posted by IshaanIan

Why did the left side headlamps require replacement in the first place? I have seen so many new Tata vehicles (under 5 years old) with drls or lights not working on one side and wondered what causes such basic things to fail on these cars.

Mostly a accident case that would not be covered under warranty? there does not seem to be any other logical explanation.