Battery care on leaf new / used

k123456

Hi Folks taking delivery of a new leaf 24kw, and am keen to make sure the batteries last for years to come

We are short distance drivers, sometimes we leave car at home (so will be doing moderate mileage). Will have access to home charger and hopefully a dedicated charge point in work


Do fast chargers eventually damage battery
Should I charge car to 80 % and stop charging at 80%
If so is there a way to use the cars technology to do this


As mentioned, some days we wont need to use the car, is leaving the car on full charge, for extended periods a problem

When charging, it is important to charge when the batteries have run down
or can they be topped up when at 60/ 70 % etc.



Thanks

BoatMad

k123456 wrote: »

Hi Folks taking delivery of a new leaf 24kw, and am keen to make sure the batteries last for years to come

We are short distance drivers, sometimes we leave car at home (so will be doing moderate mileage). Will have access to home charger and hopefully a dedicated charge point in work


Do fast chargers eventually damage battery
Should I charge car to 80 % and stop charging at 80%
If so is there a way to use the cars technology to do this


As mentioned, some days we wont need to use the car, is leaving the car on full charge, for extended periods a problem

When charging, it is important to charge when the batteries have run down
or can they be topped up when at 60/ 70 % etc.



Thanks

Others will have views on this ,but I now own a 30 kW and as an electronics engineer I design with lithiums

In my view the cars systems really ensure you can't do any real damage to the battery as it regulates charging rates based on temperature etc.

The 80 % perceived " benefit " comes from early leafs, in reality the charging system decides wihat is 100% etc. And tapers charge to ensure no overruns . There no magic 80 % benefit point on a lithium charge curve in reality

As a general rules therefore

1. I would avoid too many short , Ie 90% to 100% charges
2. If leaving the cars for a long time ( IE weeks ) , try and leave it on 40-60 % charge.
3. Lithiums have a finite life , so they prefer to be used , most lithiums die from age rather then use . They age even when not being used


There was and still is a kind of peculiar fascination, especially amongst early adopters at constant " battery navel gazing " , gids, cell balance , with instant diagnosis being offered often by those with a " little knowledge " often on the back of statisically very dubious conclusions

We happen to live in a country ideally suited to Li use with little extremes of temperature , so just in general charge your car to suit your lifestyle and " go " there is very little you can do that really influences battery wellbeing ( except use and age)

nokia69

BoatMad wrote: »

The 80 % perceived " benefit " comes from early leafs, in reality the charging system decides wihat is 100% etc. And tapers charge to ensure no overruns . There no magic 80 % benefit point on a lithium charge curve in reality

I think that depends on the pack and the chemistry used, Tesla tell people to charge to 80% for most day to day driving, and the early Volt packs were kept between 20-80% but they have changed that once they learned more about the batteries

If you intend to keep the car well beyond 3 years then there are some things you can do that will help to maximise the time the leaf stays above 70% capacity which the battery industry deem end of life for batteries.

One of the very worst things you will do to the battery is to keep it above 80% all the time, very high and low states of charge are not ideal for Lithium batteries and introduce more stresses. So I would say use the charge to 80% function in the Leaf, I don't know if it exists on the 2016 model ? even if it doesn't then you'll learn after a while how many hours takes it to a certain %.

When I'm off shift and don't need the car or maybe for pottering about I charge it to 70% and that will do me a day or two and I charge it back up at 30% back to about 70%. I charge it for what I need.

The manual states to charge it only when it goes below 80% and I would do this.

What I wouldn't do is have the leaf set that it starts to charge every time you plug it in, for instance, drive it for 10 kms and plug it back in at 90% and have it charge back to 100% , I wouldn't do this.

While fast charging itself on the 2014+ Leaf isn't (as much of a big deal) any more it could be an issue if it gets hot and you charge it beyond 80%, what's too hot ? well I would say anything from 7 temp bars +, High states of charge and high temps are well known by battery manufacturers to put the greatest stresses on batteries. So I would allow it to cool to 5 bars again before charging, of course if you are out on a long trip and it can't be avoided then I wouldn't worry about it if it's only an odd time.

When the Gen II 300+ Km electrics start to appear then I don't think battery life would be an issue because while it will still suffer from the same effects as any Lithium battery the major difference is the fact it has a lot more capacity and even a 10% loss isn't going to be a big deal, it's only a big deal if you will miss that 10%.

The Current Gen Leaf 24 kwh battery from 2014 is without doubt a lot better.

GM use only 50% of the Volt/Ampera battery and they didn't do this for the fun of it and one Volt that has reached 300,000 miles has shown no loss of capacity.

At the end of the day , if you ever needed a new battery Nissan Ireland now allow a new battery to be installed for 5,500 Euro's, come 5+ years time and this cost will be half or maybe less.

Toyota charge a ridiculous 2,500 Euro's for a Prius battery installed, and the prius has 1 kwh capacity with only half usable, compared to the Leaf with 24 Kwh and 22 usable, that's some price difference and the Prius uses older NiMh batteries !

Toyota use 50% capacity to ensure the battery lasts a very long time also.

macnab

As an addition to the previous advice, it is my understanding that the last 2% of the charging cycle ballances the Li-ion cells, for this reason I tend to do a 100% charge about once a week.

Yes balancing is done at the top if you want to ensure all cells are balanced then don't set an end timer, if the timer shuts off so does balancing.

BoatMad

I , as many know here, don't agree with mad lad and his battery advice , but rather then deal in anecdotes

Let's deal with the 80% issue.

The whole 80% issue stems from the early days of lithiums and more importantly from early charger design. Manufacturers of chargers didn't understand the charging cycle and chargers often overshot or the end point was set too aggressively.

This resulted in hot batteries and the build up of 80% advice. It was very little to
Do with li chemistry.

Today we have far more understanding and better ICs to control charging, also battery manufacturers have more info on tapering and charge end points.

Hence in reality the 80% advice on a modern Li is really in the realm of old wives tales at this point.

Yes retaining a Li for weeks ( note weeks ) at Li has shown to slightly decrease life times , again this was a holdover from lead acid charger design and early chargers tried to " float " lithiums or had a very low hysteresis and switching back on too aggressively. These issue were most prevalent in early laptops and phones and other " battery backup " applications

Today charging to 100% and leaving the battery for hours or a day or two , will have negligible effect on overall life

Yes if you are off to Tenerife for a few weeks , try and leave it under 100 %

Heat is an issue , but the latest leafs have more agressivec heat related charge control. So once you are within the recommended normal temp limits , charge away. The leaf will throttle the current of the battery charging if it gets too high.

As a design engineer , it always annoys me that ill informed users try and " outthink " the relevant design engineer. Even at worst case , the design engineer knows more then the vast majority of users and his knowledge will be encapsulated in the software controlling the system.

Sure , it's a fallible process and occasionally there are mistakes. But each iteration improves on the original.

So try not to outthink the people that designed it.

The factors degrading Li are primarily usage and life tine, assuming the basic charging parameters are designed appropriately. If you expect high usage , you will wear the battery out over time. There's no free lunch

BoatMad

Deleted User wrote: »

Yes balancing is done at the top if you want to ensure all cells are balanced then don't set an end timer, if the timer shuts off so does balancing.

As is charging the 12v

Worst case is that you pay 5,500 Euro's for a new battery when the range becomes an issue, in 5+ years depending on mileage, usage etc .

So say in 5 years the cost could be half that again.

Remember a Prius battery costs an outrageous 2,500 for a 1 kwh NiMh old skool battery, compared to the Leaf which has 24 Kwh of Lithium !

The battery doesn't die but it slowly looses capacity and it's only when it becomes a problem then it's time to get a new one.

A 10% loss won't effect me, not even 20% because I've work charging, so the battery in theory could last me 8-10 years and possibly more. It would become a problem if I wanted to take a long trip in one go, so what is a dead battery for one person might be perfectly usable for another. The idea is to be as kind to the battery as possible if you want it to last as long as possible before that range becomes an issue.