Probability question

[CoryAnan]

Hello fellow EV enthusiasts,

I have a probability question for you, based on your knowledge of the i3 at the moment:
-Imagine you have to do 100Km a day.
-Imagine you charge 100% every day.
-Imagine that in 30% of the year, the temperature will be 0ºC or 35ºC. The other 70% will be around 24ºC.

What would you think the probability of the i3 capacity reach 70% before 8 years, is?


In Portugal, the leaf’s battery has warranty of 5 years and if its capacity drops below 70% or it loses the 9th bar (within warranty), Nissan replaces it. But it is not certain that Nissan replaces it for a new one. They can replace it for one with 10 bar capacity (around 80%)
In BMW case, do you know if the replacement is for a new one or these issues are also in the limbo?

Regards,
LD

 

[TomMoloughney]

Hello fellow EV enthusiasts,

I have a probability question for you, based on your knowledge of the i3 at the moment:
-Imagine you have to do 100Km a day.
-Imagine you charge 100% every day.
-Imagine that in 30% of the year, the temperature will be 0ºC or 35ºC. The other 70% will be around 24ºC.

What would you think the probability of the i3 capacity reach 70% before 8 years, is?


In Portugal, the leaf’s battery has warranty of 5 years and if its capacity drops below 70% or it loses the 9th bar (within warranty), Nissan replaces it. But it is not certain that Nissan replaces it for a new one. They can replace it for one with 10 bar capacity (around 80%)
In BMW case, do you know if the replacement is for a new one or these issues are also in the limbo?

Regards,
LD

BMW hasn't announced the specifics with regard to the battery warranty especially as it pertains to capacity loss. The capacity loss has a lot of factors other than the age of the battery so just saying 8 years may not be enough. Let me ask you this:

-Will you only charge once per day? The amount of times you charge affects the life of the battery
-When it's hot outside (35 degrees) can you park it under cover or will it be baking in direct sunlight in an open parking lot all day? If it is, the battery cells will likely get as hot as 45 degrees at times and that's not really good for them.
-On days that you know you'll only be driving 100km or less can you not charge it to 100%. One of the best ways to help extend your battery life is to only charge to 80% and to not take the charge less than 20%. Keeping the state of charge between 20% & 80% will definitely help exited it's life. Now obviously you can't do this all the time, but if you really want to help keep the battery healthy as long as possible, then keep this in mind.
-How many km do you plan to drive over the 8 years? Total mileage is as important as age.

All that in consideration, if you do take good care of your battery and you drive about 160,000km in 8 years I think 70% capacity should be right around where you'll be at by then. 3 to 4% annual capacity loss is about right for normal use and good care.

 

[ChrisC]

To directly answer your question, I think the warranty numbers are conservative, and there is only a 25% chance that the i3's battery capacity will reach 70% before 8 years.

That's only my opinion, but I have been watching this business for a while

 

[AndrewDebbie]

The i3 uses the cars air conditioning system to actively cool the battery pack.
Leaf doesn't have anything like that. An i3's pack shouldn't get anywhere near as hot as a Leaf's during charging.

Optionally, the i3 can also heat the pack when charging in very cold weather. Selecting this option will help with winter range.


The coolant lines enter the lower left corner of the pack in this photo:

 

[surfingslovak]

The i3 uses the cars air conditioning system to actively cool the battery pack.
Leaf doesn't have anything like that. An i3's pack shouldn't get anywhere near as hot as a Leaf's during charging.

Optionally, the i3 can also heat the pack when charging in very cold weather. Selecting this option will help with winter range.

Indeed. According to what Tom has been able to learn from BMW, the i3 should have a very sophisticated thermal management system, which will help with both hot and cold conditions. That said, the underlying lithium-ion cells are temperature sensitive, and it would be good to keep that in mind. The cooling system will help keep them healthy and happy, but certain precautions, such as making sure that the cooling system can operate when going on vacation and leaving the car behind are advisable.

The Tesla Roadster was the first serial vehicle to use this type of technology, and a recent survey conducted by Plug In America revealed that Roadster owners have been able to keep their battery packs in better than anticipated condition even in hot places like Arizona, which is much hotter than Portugal and notorious for its harsh conditions. Let's hope that the i3 batteries will hold up equally well or perhaps even better.

According to a post by Pieke on another thread, BMW seems to be offering a capacity warranty in the Netherlands. Let's hope that this will be the case in other countries as well. This type of coverage removes a lot of uncertainty, and really helps with the adoption of this technology.

The BMW lithium-ion battery is characterized by its longevity. For the
first 100,000 kilometer and up to 8 years defects in the battery of your BMW i3 will be repaired and a maximum capacity of 70% guaranteed.

 

[CoryAnan]

Hi,

Answering Tom:
Yes, I can only charge once a day. When too hot or too cold the car will have to stay outside, no protection or shade, can be provided.
In 70% of the year I will be able my daily commute with an 80% charge.
In 8 year I am sure I will be making no less than 220000 Km.

By the 4th year the warranty will be lost. But for me, to be a good deal, I have to stay with the car at least 10 years (call it an investment). EV’s have a very, very poor 2º hand market. (Except when with very few Km)

Andrew, when you say “The i3 uses the cars air conditioning system to actively cool the battery pack.” Does this mean, when too hot, that I have to drive with AC on? Or can I choose to direct the air only to cool the batteries? How much is the drain on the batteries?
Also, “Optionally, the i3 can also heat the pack when charging in very cold weather. Selecting this option will help with winter range.” This option is an optional ($€£) or something I can select when going to put on charge?

Sorry for the newbie questions. I thank in advance for your replies,
LD

 

[TomMoloughney]

Hi,

Answering Tom:
Yes, I can only charge once a day. When too hot or too cold the car will have to stay outside, no protection or shade, can be provided.
In 70% of the year I will be able my daily commute with an 80% charge.
In 8 year I am sure I will be making no less than 220000 Km.

By the 4th year the warranty will be lost. But for me, to be a good deal, I have to stay with the car at least 10 years (call it an investment). EV’s have a very, very poor 2º hand market. (Except when with very few Km)

Andrew, when you say “The i3 uses the cars air conditioning system to actively cool the battery pack.” Does this mean, when too hot, that I have to drive with AC on? Or can I choose to direct the air only to cool the batteries? How much is the drain on the batteries?
Also, “Optionally, the i3 can also heat the pack when charging in very cold weather. Selecting this option will help with winter range.” This option is an optional ($€£) or something I can select when going to put on charge?

Sorry for the newbie questions. I thank in advance for your replies,
LD

Yes the car will cool the batteries by itself when it needs to, you will not have to turn on the Air conditioning in the cabin.

220,000km is a lot of miles. I'm not going to pretend I can give you a definite answer on whether or not you will still have 70% capacity at that many miles and after 8 years. Gun to my head, I'd say no it will not, but BMW has been really promoting how proud they are of the battery management system they have engineered for the i3 so if it's as good as advertised, then perhaps 70% after 220,000km will happen.