[[email protected]]

Hi everybody, what are the best tips and tricks to maximize life expectancy of the i4 battery?

The first tip is in the manual of the i4: set charge goal at 80%.

Does anyone have tips that maximize battery life like:

• Charge frequency? (Often and small charge quantity or fewer times and large charge quantity)
• Slow/fast charging? (11KW vs 150-200KW?)
• etc...

 

[Ken7]

Fast charging should not be done on a frequent basis if battery longevity is your concern. Occasional fast charging on trips is fine, but don't do it on a regular basis. This could be a real temptation if you live near a fast charger, since BMW-USA gives you 2 years of daily 30 minute charging. Resist!

 

[Masque]

You’re not going to like this, but be aware that batteries are startlingly mechanical in their physics. Filling them too fast and emptying them too fast will basically cause wear. That’s the short version, anyway – so a light foot and gentle charging should make the thing last a very, very long time.

Now, it also seems that BMW have gone to great lengths to protect you from yourself here, so it’s difficult to say how much of a difference rapid acceleration and rapid charging will make over time. Each instance probably the smallest difference. To what will they add up? We will know in five years…

 

[Jpuff]

Slow charging, slow acceleration, slow deceleration, never a full charge, never a low charge, and who cares? Drive it like you rented it.

 

[[email protected]]

To what will they add up? We will know in five years…

I would love to compare batteries & driving styles between different drivers on this forum. But so does BMW I guess 😅

 

[VolM]

In the BMW i3 there was a secret menu (without using an OBD) in which one could read-out the maximum battery capacity.

Does anyone know whether there is such a menu in the i4, including a description of it?

 

[BadgerGreg]

Fortunately, automotive engineers have been fairly conservative with HV battery design, and even those drivers who road trip a lot and use DCFC frequently are finding relatively low degradation, even after 150,000+ km. Based on my research and talking to EV owners, most HV battery systems will degrade between 5% and 10% after 150,000 km. I suppose if you are careful and seldom charge above 80%-90% and use DCFC sparingly, you might end up closer to the lower end of that range (5%).

Given that the degradation range doesn't appear to be very wide, despite various types of use, the best recommendation would be as follows:

1. Charge at home using Level 2 to 80% daily (90%-100% when needed)
2. Use DCFC when on a road trip, but don't worry about the frequency of DCFC as long as you stick to Level 2 when you have that as an option.
3. Don't be afraid to shred it every once in a while. I'm sure the occasional burst of electrical draw from the battery is well within the design spec of the battery. BMW wouldn't warranty the battery for 100,000 miles if that wasn't the case.

 

[VolM]

I’m looking for something like this:

(secret menu BMW i3)

If this is possible in the i4 then I can figure out what the capacity of the battery Is short after delivery and any time later on. If this is not possible I’am dependent of the dealership For this information.

 

[Z-Zada]

Fortunately, automotive engineers have been fairly conservative with HV battery design, and even those drivers who road trip a lot and use DCFC frequently are finding relatively low degradation, even after 150,000+ km. Based on my research and talking to EV owners, most HV battery systems will degrade between 5% and 10% after 150,000 km. I suppose if you are careful and seldom charge above 80%-90% and use DCFC sparingly, you might end up closer to the lower end of that range (5%).

Given that the degradation range doesn't appear to be very wide, despite various types of use, the best recommendation would be as follows:

1. Charge at home using Level 2 to 80% daily (90%-100% when needed)
2. Use DCFC when on a road trip, but don't worry about the frequency of DCFC as long as you stick to Level 2 when you have that as an option.
3. Don't be afraid to shred it every once in a while. I'm sure the occasional burst of electrical draw from the battery is well within the design spec of the battery. BMW wouldn't warranty the battery for 100,000 miles if that wasn't the case.

Great and sensible advice. Thanks.

 

[Elle BMW]

I wonder why it's 80% and not 85% of the battery? of course I'm not an engineer so I don't have that answer. I anticipate charging it about once a week once it's charged to 80% well, after the first few months of fun driving that is. Or should I top it off every night?

 

[gsbaker]

I wonder why it's 80% and not 85% of the battery? of course I'm not an engineer so I don't have that answer. I anticipate charging it about once a week once it's charged to 80% well, after the first few months of fun driving that is. Or should I top it off every night?

It is a round number of the percentage where the charging slows while fast charging. The migration of the battery chemicals slows as you get a smaller percentage in the uncharged form.

For home charging I don't notice the rate being slower to go to 100% since it is anyway overnight. Also, when I charge overnight I look at the estimated completion time and lower the charging current until it just reaches 80 or 100% by morning. That should put less heat into the battery.

There is a "preconditioning" setting, but I think that one waits to start charging until just in time, rather than lowering the current.

When I want to drive 2-3 hours into the mountains I slow charge to 100% because there are few chargers there, and you have to "lend" range to go up the mountains. So you use more range than the distance traveled.

If you drive in B mode you get back the range you used to climb. I find that I can gain 40 miles of range going down the mountain. So I like to keep the buffer for going up.

To drive shorter trips I just bring it to 80%. I see no reason to charge every day. Your remaining charge and range is always on the instrument screen, so there is no suspense.

Plus, once you know where the public chargers are in the region you can plan on hitting those. I don't use the fast chargers past 80%, since they slow down after that and you pay by the minute.

BMW gives us 30 minutes free charging at EA. That is enough to go from 30% to 80%.

You will see your car soon. Enjoy it.

 

[Masque]

Preconditioning uses power to heat or cool the battery (and cabin) for optimal battery conditions upon departure. It does not delay charging.

 

[Jpuff]

I wonder why it's 80% and not 85% of the battery? of course I'm not an engineer so I don't have that answer. I anticipate charging it about once a week once it's charged to 80% well, after the first few months of fun driving that is. Or should I top it off every night?

Some engineers looked at a curve on a chart of values then said to their middle manager, "76.5% is optimal." Then that person talked to the actuaries then the marketing people then the sales people. A committee met. Finally they came back and said, "80% is close enough, jah?" and the engineers shrugged then agreed.

 

[Ken7]

BMW gives us 30 minutes free charging at EA. That is enough to go from 30% to 80%.

That’s exactly what I saw the other day. I went from about 31% to 80% in 27 minutes. I was hoping for a bit more charging speed, but I guess it’s fine.

 

[Magicrat]

That’s exactly what I saw the other day. I went from about 31% to 80% in 27 minutes. I was hoping for a bit more charging speed, but I guess it’s fine.

Do you happen to remember what charging speed you started and ended with?

 

[gsbaker]

Do you happen to remember what charging speed you started and ended with?

I was plugged into a 150 kW station. I did not notice the charging rate but the last time took about 22 minutes, so the average was over 100 kW.

 

[gsbaker]

Here is a graph posted here a few months ago.

Has anyone posted a charging curve for the i4 yet?

Seeing that the i4 is now being delivered in Europe, has anyone done a detail charging curve for the battery? Knowing this info will give you an idea of how long you will be at charging stations when doing a long drive. If it charges slow at say 70% state of charge (SOC) it would be better to...

www.i4talk.com

Looking at the track from 30-80% shows the rate would average between 90-100 kW.

Also, starting from 30% battery, it doesn't much matter whether you plug into the 150 or 350 kW station at EA. You might get up to 180 kW for a few minutes only.

 

[Ken7]

Do you happen to remember what charging speed you started and ended with?

I started with, or should I say peaked at within the first minute or two, at 137kW. So I was not getting the full 150kW the charger was labeled at. I think I ended somewhere in the neighborhood of 50kW. Next time I’ll try a different charger.

 

[i4m50Norway]

I wonder why it's 80% and not 85% of the battery? of course I'm not an engineer so I don't have that answer. I anticipate charging it about once a week once it's charged to 80% well, after the first few months of fun driving that is. Or should I top it off every night?

My understanding is that the very best for the battery is to store it with 50 percent charge. The best strategy is probably to charge it when it comes down to 30 - 40 percent, and then charge to 80. This is of course dependent of how much unexpected driving you will prepare for.

I also think that it is just a car - that will have limited life, and loose value after some years. On my i3, when having limited use of the car. I usually charge it after weekend drive, and then I charge it again on Thursdays - to be ready for the weekend. When planning a longer drive - I always try to have it 100 charged with the slow home charger.

 

[BadgerGreg]

Here is a graph posted here a few months ago.

Has anyone posted a charging curve for the i4 yet?

Seeing that the i4 is now being delivered in Europe, has anyone done a detail charging curve for the battery? Knowing this info will give you an idea of how long you will be at charging stations when doing a long drive. If it charges slow at say 70% state of charge (SOC) it would be better to...

www.i4talk.com

Looking at the track from 30-80% shows the rate would average between 90-100 kW.

Also, starting from 30% battery, it doesn't much matter whether you plug into the 150 or 350 kW station at EA. You might get up to 180 kW for a few minutes only.

Yep - the 210 kW max charging only occurs at very low SOC (between 0%-20%), then tapers down to 150 kW after 20% and then down to 110-120 kW between 30%-40%.

I look at it this way; whether you start charging at 5% or 25% SOC, it generally takes about 30 minutes to get to 80%, assuming you have a 150 kW+ charging unit. I plan my charging stops for a 30-minute charge; this almost always puts me back at 80% (+/-). As always, be sure to program in the charging station as a destination or waypoint in BMW's nav system so the car can precondition the battery...that will be even more important during colder months.