Tata Nexon EV max: Fast charging attempt leaves me stranded
It was clear that the issue is the “contactor welded” error flag as the Star make DC chargers Relux uses is a common offender and needs to be reset for fast charging to work again.
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Thought I’ll pen down the recent adventure I had with the Max. The last weekend, I was travelling from Kochi to Bengaluru. We started at around 6 AM, and the plan was to have breakfast and recharge the car at Sree Annapoorna, Avinashi. However, as we were nearing the station, when we checked the Zeon app, the charger was marked un-available so we thought we’ll stop at the next station Haribhavanam Avinashi 5 km or so away. On the way we drove by the Sree Annapoorna station, found the station offline, and the security guard told us there is a scheduled power cut and would be back only by 5 PM or so. We proceeded towards Haribhavanam Avinashi, and only once we reached there we realised the restaurant opens only at 11-11:30 and there were no other open restaurants nearby. Anyway since we reached the place, we decided to plug-in and get a quick topup before proceeding to the next station. Charged for 30 min, was un-eventful, meanwhile checked the status of the next station which is Relux Perundurai. The station was marked as busy, so we decided, will stop there if it becomes free by the time we reach (around 30 min drive, 40 km) if not, will proceed towards Saravana Bhavan, Sankari. I was bit hungry as well, so we really hoped the Relux Perundurai station was free by the time we reach else the Sankari Zeon is another 50 km away.
Reached Relux Perundurai and luckily (or was it really unlucky ) the station was free, so plugged the car in, worked on first try, all good. Went to the adjacent A2B, ordered breakfast. Maybe a few minutes in, the power went but was restored quickly after. Checked the Relux app, and sure enough no update. Couple of minutes later got the SMS/Email saying charging completed, as the station rebooted. I couldn’t restart charging remotely, as the status went to “Preparing” and the station was marked busy. So I walked towards the car, removed the gun, plugged it back in and restarted charging. No issues at all at this point, started charging on first try. So I went back to the restaurant, finished our breakast, by now it had charged to around 84% or so. Thought will stop at 90%, so I set the charging limit on the ZConnect app to 90% (first time I am trying this). We took a short stroll, checked out a handicraft store at the location, and in a couple of minutes, got a notification saying charging is complete, with SoC at 90%.
(At Relux Perundurai with our curious pet cat peeking . The remote pre-cooling feature in ZConnect is really a boon when we have to leave our cat inside the car during stops)
Got in the car and this is when I noticed a warning light in the console.
Checked the owner’s manual and it indicated some sensor failure. It was really hot and the car was charging under the sun, so I initially just attributed it to the high temperature causing some malfunction as the warning description talked about high temperature as well and hoped it would clear on its own in sometime. We started driving and didn’t notice any real issue. I also posted in the Nexon EV Owners group in Telegram, but not many had seen this warning. I later realised that this warning is new to the Max and not there in the EV/Prime. I tried restarting the car a few times sometime later to see if the warning goes away, but it did not. Our next stop was planned for Surya Complex, Krishnagiri. We also checked Hotel Alps Residency, Krishnagiri which is a Relux station as it was a bit cheaper, but was offline.
Reached Surya Complex with 14% SoC, the 50 kW station was occupied by another car (a BMW electric), so we used the 24 kW station. Parked the car, connected the gun, and used my RFID to initiate charging, and immediately it threw an error saying that the station couldn’t communicate with the car. Tried a bunch of times, unlocked and relocked the car etc, but no luck. The moment charging is initiated the error was thrown, so it was not like it took some time to error out. Since the last two stations were Relux and it worked, thought it could be some Zeon issue. There was a new Relux open at HPCL Schoolagiri, 20 km away, and thought we could make it. Drove slowly and reached the station with 8% SoC or so. Once it reached 10% SoC, vehicle went into limp home mode. Anyway fast charging failed to work at this station as well, error was “EV Parameters Overtime” this time. At this point it was pretty obvious that the charging is failing due to some error in the car and the amber warning is related to the issue.
At this point I wasn’t sure what to do, as slow charging will take hours if at all it worked. I reached out to the Tata RSA and even though they were very helpful, the best solution offered was to tow the car that too to Salem (150 km away) as that is the closest service centre which deals with EVs. To be noted here is that there are Tata service centres in Hosur (15 km away) and Krishnagiri (30 km away), which as per their system do not deal with EVs. There is also another service centre just after Electronic City as well. When asked why can’t it be towards to the SC at Bangalore, they are like it has to be within the state of breakdown, else I need to pay some cross border towing surcharge of Rs 2000 or so. Anyway I didn’t want to get towed right away so I asked them to call me back in some time.
I had also read user reports about a “contactor welded” error code / soft fuse that prevents fast charging that can be cleared only by the SC. I had posted in the Telegram Owner’s group about my predicament, and a kind gentleman who is very familiar the Nexon EV and with the various charging errors and issues, reached out to me. We went through some basic checks
At this point, from his experience so far, it was clear that the issue is the “contactor welded” error flag as the Star make DC chargers Relux uses is a common offender and needs to be reset for fast charging to work again. The kind gentleman then reached out to a contact of his, a senior Tata official. Long story short, after a bunch of calls, within 30 min, a Tata technician was on his way from Krishnagiri with the laptop to clear the fault codes. While the discussion with Tata was ongoing, I was also checking if any of the restaurants can let me slow charge. Checked with a Frozen Bottle outlet, and they were very helpful when we told it was an emergency. However, even though it started charging, couple of minutes in, their MCB tripped due to overload. Then checked with a tyre shop within the same area which kindly let us slow charge. Charged for 30-45 min, but their fuse blew, and the whole shop lost power. SoC now stood at 11%. By now, the Tata technician arrived, straight away connected his laptop to the OBD port, scanned and could see the dreaded “contactor welded” error code. He cleared the faults and reset the fast charging status to OK and applied the changes. The whole process took less than 5 min.
At this point, as there was no other option, used the Relux station (same StarCharge make). This time fast charging worked and was able to charge. Thought will charge to 100% as I had some other errands the next day, and slow charging point is not ready at my house in Bangalore yet. So if I do end up with the same error flag again, I may not be able to fast charge. Luckily this time it charged to 100% without any issues, and we were able to drive home without any problem.
(Charging at HP Junction, Shoolagiri)
- 3:30 PM – Reached Surya Complex, Krishnagiri
- 3:50 PM – Left Surya Complex, Krishnagiri
- 4:15 PM – Reached HP Junction, Shoolagiri
- 9:05 PM – Left HP Junction, Shoolagiri
So our trip got extended by 5 hours as part of this adventure. It was definitely stressful and we were very fortunate to get the help from the Owner’s group and from Tata for arranging the technician to come help us get back on the road. If went the RSA way, as it was already a bit late, I don’t think we’d get the car back until the next day. Also, the car was full of luggage, and our pet cat and her kitten, so we are very glad that we didn’t need to get the car towed.
TL;DR – Relux StarCharge make DC fast chargers can cause the Nexon EV to trigger a soft fuse preventing future fast charging, until the fault is cleared by Tata SC. Potentially leaving you stranded during long trips.
Read BHPian comments for more insights and information.
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