[Vindi13]

Hello, it has been a year with the Nexon EV without a single issue. I use a wall-mounted slow charger at home. the last few weeks, i notice that overnight charging takes it to only 75-80% from 10-20%, while it used to reach 10% by 5 am earlier (approx 10% increase per hour). Anyone else has faced this problem? What could be the most possible cause?- the battery, charger, or power line/supply?

[ferrarirules]

Originally Posted by Vindi13

Hello, it has been a year with the Nexon EV without a single issue. I use a wall-mounted slow charger at home. the last few weeks, i notice that overnight charging takes it to only 75-80% from 10-20%, while it used to reach 10% by 5 am earlier (approx 10% increase per hour). Anyone else has faced this problem? What could be the most possible cause?- the battery, charger, or power line/supply?

Check if the charger shows a blinking red light on the 4th led which means that the plug is getting hot. That could be due to voltage fluctuation or weak earthing combined with higher ambient temperature

[ev_wannabe]

Originally Posted by silvy_rider

UPDATE: Got the issue resolved which involved changing the battery pack.

Initially the service centre tried resetting the car and sent her back assuring that they will properly investigate if the the issue re-appeared
(They didn’t also bother to charge the car and returned it with 12% SoC )
However the issue happened again the very next day
This time the service centre folks were more prompt and called in a “EV expert”.
They kept the car for 4 days during which the battery pack was replaced.

The car has been working fine from the last 2 weeks with proper range and expected charging times.

As a new owner, I am shocked at the number of cases with the battery pack. I am doing some research on battery life, and I am finding that most users are following charging patterns that degrade battery life, and seem unaware of it.

Here are the reccomendations for charging-discharing that I have learned so far. This should battery 101, that should be distributed with every EV, I feel.

1. Using a charge cycle of 75% - 25 % more than doubles the battery life. Even on prime this gives you 100 Km, so it should be more than sufficient for daily use. This should be your main charging pattern
2. Avoid keeping your car for a long time charged higher than this, and similarly avoid discharging your car below 25%. You can charge as frequently as possible with lithium chemisty.. so you dont have to wait for battery to drop below 25, following a pattern like 75%-40% also works just as well.
3. When parking your car in storage for long time keep it charged around 60% or so.. This should slow down the ageing of the battery.. keeping it charged at close to 100% and leaving it for some time, significantly speeds up the ageing of the battery.
4. The battery pack is made of many individual cells. There is a phenomena called cell imbalance that occurs, where some individual cells charge less than the others, and overtime their voltages can drop quite low, which can cause the battery pack to shut down.. To avoid this once in 4-5 charges or so, it is reccomended to break 1., and *slow* charge all the way to 100%.

That's it. Hope you find the above tips useful.

[ferrarirules]

Originally Posted by ev_wannabe

A
1. Using a charge cycle of 75% - 25 % more than doubles the battery life. Even on prime this gives you 100 Km, so it should be more than sufficient for daily use. This should be your main charging pattern
2. Avoid keeping your car for a long time charged higher than this, and similarly avoid discharging your car below 25%. You can charge as frequently as possible with lithium chemisty.. so you dont have to wait for battery to drop below 25, following a pattern like 75%-40% also works just as well.

This is not right. I am part of the Nexon EV whatspp group. The people who are long timers who have driven their prime for 70k plus kms say that charging to 100% every time is not a problem. They say you should usually charge till 100 as the BMS balances the sell above 80%. Also, charging from below 20% is recommended after maximum 3 charges.

What you have written is true for Lithium NMC batteries but not true for LFP batteries.

[EV Fan]

Originally Posted by Vindi13

What could be the most possible cause?- the battery, charger, or power line/supply?

Originally Posted by ferrarirules

Check if the charger shows a blinking red light on the 4th led which means that the plug is getting hot.

as mentioned, check if the cable & plug are hot when the charging stops. also if the vehicle charges perfectly via other means - is it the charger fault and not the electrical..

If it is getting hot but not an issue with charger, then quickly try to trouble shoot the electrical.
- Low voltage or PF during charging time causes more current to be drawn by the charger to cater to the load. Heats up the electrical's & the plug. the charger cuts off usually preventing any other issue. seen this quite a few times here...
- If the voltage is not the culprit then better check the electrical setup (wiring to the plug) - any indication of damage/burning... this can happen even with new cables...improper gauge/length, damage during in internal routing etc (initially seems to work fine whereas it is deteriorating gradually)

[shibujp]

Originally Posted by Eco_boost

Got the 6 Months Service Done yesterday!

ODO - 6500 +
- Total Bill - 6014
Attaching a copy of the invoice.

I feel that the service charges are quite excessive for an EV. Given the absence of mechanical parts it should be quite cheap. This is expensive even by ICE standards. The price of electric technology is already charged during selling the car.

Also what is this transmission oil change business. Automatic transmissions for ICE that go through millions of shifts in their lifetime are almost never changed so why do EV transmission oils need change?

Drive on,
Shibu

[ev_wannabe]

Originally Posted by ferrarirules

This is not right. I am part of the Nexon EV whatspp group. The people who are long timers who have driven their prime for 70k plus kms say that charging to 100% every time is not a problem. They say you should usually charge till 100 as the BMS balances the sell above 80%. Also, charging from below 20% is recommended after maximum 3 charges.

What you have written is true for Lithium NMC batteries but not true for LFP batteries.

Your are right the data I used does not specify it is for LFP.

Googling "LFP Depth of discharge", returns some conflicting information, but the majortiy of the reccomendations are to not do a full cycle but instead do 80% or 90%, i.e charge to 90% and discharge upto 10% . However they dont really show any curves to justify that.

Several of the LFP Battery manufacturer webpages do show a clear relationship between the DoD and life cycle.. and following 50% DOD does improve battery life 2x over 100%DoD.

Here is a list i could google.
https://www.competasolar.es/lfp-battery/
https://www.powertechsystems.eu/home...phate-lifepo4/
https://www.bravabatteries.com/lifep...-charge-curve/
https://community.victronenergy.com/...ns-for-li.html

So I do standy by my original reccomendations. Maybe it can be relaxed a bit more, but definitely avoid charging over 90% majority of the time.

As for balancing the battery, it is sufficient to only do this once in every 4-5 charges. This reccomendation comes from TATA itself.. (

https://www.youtube.com/watch?v=-Zz5-D2o6Gc

)

Hope that helps alleviate your concerns, but the original reccomendations are still good.

[ferrarirules]

Originally Posted by ev_wannabe

Your are right the data I used does not specify it is for LFP.

Googling "LFP Depth of discharge", returns some conflicting information, but the majortiy of the reccomendations are to not do a full cycle but instead do 80% or 90%, i.e charge to 90% and discharge upto 10% . However they dont really show any curves to justify that.

Hope that helps alleviate your concerns, but the original recommendations are still good.

The depth of discharge vs cycles means the maximum amount of discharge and its relation to number of cycles.

First of all nobody discharges their battery to deep discharge which means 0%. We can safely assume that if we discharge till 15% charge, we are discharging max 85% of the battery. At 85% DOD, you will get 4000 cycles from the battery

Below is the excerpt from one for the link you provided

In standard environment, and for 1C cycles, we can get from the chart the below life cycle estimation for LFP :
3 000 cycles at 100% DoD
4 500 cycles at 80% DoD
10 000 cycles at 60% DoD
etc.
It should be noted that following the number of completed cycle, the batteries still have a nominal capacity > 80% of the original capacity.

So say you are driving EV Max and you are getting a modest range of 260 kms. You can drive it 10 lakh kms and still battery SoH will be at 80%. Finally none of the articles say that you should not charge it to 100% or that it has any impact.

Rest you can read the Tata provided owner manual. It is clearly written - It is recommended to charge up to 100%
during every charging for best performance of battery pack.

[ev_wannabe]

Originally Posted by ferrarirules

The depth of discharge vs cycles means the maximum amount of discharge and its relation to number of cycles.

First of all nobody discharges their battery to deep discharge which means 0%. We can safely assume that if we discharge till 15% charge, we are discharging max 85% of the battery. At 85% DOD, you will get 4000 cycles from the battery

I think it is commonly understood that the DoD is around the 50% mark.. (https://www.myussi.com/glossary/depth-of-discharge/).

Irrespective the data from several manufacturer is clear that shorter DoD leads to longer life.

What you are arguing instead is that this shouldnt matter, as the number of cycles are still high enough to cover 10 Lakh Km's. But I think there are also other factors at play other than charge-discharge (like calendar ageing, which again is worse at higher SOC>90%), so I think the effective number will be far shorter than the 4000 cycles, so if you can save on this dimension it still makes sense.

Anecdotal information, but I do see a high level of battery failures both in the whatsapp groups, I am on ? what would you attribute them to ?

As for the TATA reccomendation to charge to 100%, it seems similar to https://www.autoevolution.com/news/t...00-187075.html

I would highly reccomed you read the above article.. if you are still a skeptic.

Mod Note: Please quote ONLY the relevant bits of a post. Quoting a full, long post inconveniences our mobile readers.

[ferrarirules]

Originally Posted by ev_wannabe

As for the TATA reccomendation to charge to 100%, it seems similar to https://www.autoevolution.com/news/t...00-187075.html

I would highly recommend you read the above article.. if you are still a skeptic.

For the depth of discharge, higher the DoD number lesser the charge cycles the battery will support.

Nobody is saying to take the battery below 20% every time. But charging your battery to 100% is not a problem and it is written in the article sent you as well.

Keep in mind that LFP batteries already have an improved lifecycle, so having them fully charged once in a while will not impact their lifecycle significantly

Finally Tata gave a cycle limit of 2500 cycles (after taking into consideration calendar ageing, charging deterioration) which is 6,50,000 kms. After that the battery will still be at nominal SoH of 80%. According to me, if the battery conks off earlier due to the fact they asked me to charge it to 100% every time. They better replace the battery and what is big deal in getting the battery replaced.

[ev_wannabe]

Originally Posted by ferrarirules

Nobody is saying to take the battery below 20% every time. But charging your battery to 100% is not a problem and it is written in the article sent you as well.

This is definitely not what the article is saying. If anything it highlights the danger of charging to 100% evertime. In fact the article further makes a point that once charged, you cannot leave it at 100%, and have to drive the car immediately to bring down the level.

The charge to 100% is only needed infrequently, and not each time, which very much differs from what you saying.

[wocanak]

If this article is correct then, there is a trade of happening between accuracy of estimation and battery life, i.e. charging to 100% gives the best accuracy, but also reduces the life. Since LFPs have much higher charge cycles, the car OEMs have recommended an action which improves accuracy even if it reduces charge cycles. Say that reduces from ~3500 to ~2500 cycles, that is still a very acceptable 6,50,000 kms as ferrarirules points out.

Guess only Taxi/commercial car owners need to worry about this and avoid charging to 100% each time and keep DoD ~50% to squeeze. They will anyway be doing fast charging, where it is recommended to stop at ~80%.

Private car owners who mostly slow charge can charge to 100% each time and still retain more than 80% for at least 200x1500 = 3,00,000 Kms.

Basically both can just follow what is recommended in the manual and end up getting the best for their use case.

[Vindi13]

Originally Posted by ferrarirules

Check if the charger shows a blinking red light on the 4th led which means that the plug is getting hot. That could be due to voltage fluctuation or weak earthing combined with higher ambient temperature

Just checked while charging. There are 2 solid greens with the third green blinking. The 4th led doesnt blink, and definitely not red.

[ev_wannabe]

Originally Posted by wocanak

Private car owners who mostly slow charge can charge to 100% each time and still retain more than 80% for at least 200x1500 = 3,00,000 Kms.

I see many people in whatsapp group get far less than 1500 charge lifecycle.. some folks have battery running out in 2 years or so.. so I am guessing they are getting battery life closer to 500 or so cycles.. Are these all defective batteries ? I don't think so as the number of complaints seem quite high..

I suspect it is because they are following something like 100-60 cycle, where the battery on a average spends a lot of time above 80%, or leaving the car battery a long time above 90. For somebody that doesn't commute much,
and blindly charges the battery every night, can do real harm by blindly following the recommendation to charge to 100 each time. Also again driving the car frequently at less than 20 % frequently would also pull down the battery life.

The destructive behaviors above could pull down the 1500 number of charges calculation, quite dramatically.. what really matters is the how much time during its life cycle the Battery was above 80%, and how much time it was before 20%.

(Aside 100-60 is not 40 Dod, 40 dod would be 70-30, I.e. centered around 50)

[ferrarirules]

Originally Posted by ev_wannabe

The destructive behaviors above could pull down the 1500 number of charges calculation, quite dramatically.. what really matters is the how much time during its life cycle the Battery was above 80%, and how much time it was before 20%.

First of all, 2500 cycles committed by Tata are based on all the real world parameters. So if goes below that Tata needs to provide a replacement battery which they are doing.

Secondly you say a lot of battery failures, can you please quantify the number because Nexon itself sells minimum 1000 units a month.

Finally blusmart is a EV cab company, their business is centred around the cabs running as much as possible. They usually fast charge their cars and even charge them to 100% consistently. They are not reporting any battery unusual battery degradation

Originally Posted by Vindi13

Just checked while charging. There are 2 solid greens with the third green blinking. The 4th led doesnt blink, and definitely not red.

Check the voltage as that also leads to lower current being delivered by charger. If all is well in the electricals report to Tata and get your charger replaced.