vger105
Posts: 27
Joined: Sun Jan 26, 2020 3:16 pm

What's bad for our batteries?

Tue Feb 04, 2020 5:48 am

In addition to excessive heat and excessive cold, are there other things that are harmful to our i3 batteries?

alohart
Posts: 2074
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: What's bad for our batteries?

Tue Feb 04, 2020 12:14 pm

Allowing the battery pack to remain at a very high or very low charge level for an extended period of time. Even though the i3's battery management system (BMS) prevents the battery pack from being charged to its actual full charge or to be completely discharged, battery cell degradation accelerates as the charge level increases or decreases from a mid charge level range (i.e., 40% - 60%).
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

Obioban
Posts: 76
Joined: Wed May 22, 2019 6:16 am

Re: What's bad for our batteries?

Wed Feb 05, 2020 7:14 am

DC fast charging.

vreihen
Posts: 303
Joined: Tue Apr 30, 2019 4:55 pm
Location: Orange County, NY (FN21vm)

Re: What's bad for our batteries?

Wed Feb 05, 2020 10:07 am

Depending on who you ask...

Fast charging (DC or 32A Level2)
Discharging to 0%
Charging to 100%
Long-term parking
Charging too frequently
High number of discharge cycles
Charging when hot
Charging when cold
Looking at your car in the wrong way :lol:

My $0.02 is to let the battery management system do the worrying and just enjoy your car, trusting that the BMW engineers have picked the best set of tradeoffs to ensure a long and productive vehicle life.....
2015 BMW i3 BEV, Giga World, Tech and Driving Assistant packages, 15K miles

Busfolder
Posts: 26
Joined: Wed Nov 29, 2017 1:34 pm

Re: What's bad for our batteries?

Thu Feb 06, 2020 5:41 pm

Most of my charging (2016 94Ah REX) over the 26 months I've had my i3 has been done with 50kW rapids, as I mainly use the car for long trips (rarely under 100 miles...)

I've not noticed any significant loss of capacity, but if this happens I want it to do so before the battery's warranty expires (so BMW picks up the tab...)

So I'm not planning to change this strategy, as eventually I want to replace the original battery with a higher capacity unit (120Ah+?)


Chris

Obioban
Posts: 76
Joined: Wed May 22, 2019 6:16 am

Re: What's bad for our batteries?

Fri Feb 07, 2020 8:42 am

Busfolder wrote:
Thu Feb 06, 2020 5:41 pm
Most of my charging (2016 94Ah REX) over the 26 months I've had my i3 has been done with 50kW rapids, as I mainly use the car for long trips (rarely under 100 miles...)

I've not noticed any significant loss of capacity, but if this happens I want it to do so before the battery's warranty expires (so BMW picks up the tab...)

So I'm not planning to change this strategy, as eventually I want to replace the original battery with a higher capacity unit (120Ah+?)


Chris
How do you have a 2016 94aH? :?

I haven't yet seen anyone post significant degradation on a 94aH car (could just be because they don't have enough miles yet). Makes me wonder (hope) if the battery chemistry is more resistant to it.... or it might just be that the same distance traveled with the 60aH car is 1.5x as many battery cycles as the 94aH car...

Busfolder
Posts: 26
Joined: Wed Nov 29, 2017 1:34 pm

Re: What's bad for our batteries?

Fri Feb 07, 2020 1:04 pm

[How do you have a 2016 94aH? :?/quote]

I bought it used (at 8300 miles in its first year) in late December 2017, so I guess it was an early UK 94Ah car.

Just passed 28000 enjoyable and economical miles (by careful choice of public chargers- UK pricing varies wildly!)

Have recently installed the BMW Connected app, and much appreciating the remote preconditioning capability!

Chris

alohart
Posts: 2074
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: What's bad for our batteries?

Fri Feb 07, 2020 2:12 pm

Busfolder wrote:
Fri Feb 07, 2020 1:04 pm
I bought it used (at 8300 miles in its first year) in late December 2017, so I guess it was an early UK 94Ah car.
Apparently in Europe, the model year of a car is the year in which it was built. If an i3 built in late 2016 were classified as a 2017 model in the U.S. (e.g., a 94 Ah i3), it would be a 2016 model in Europe.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

panamamike
Posts: 121
Joined: Sat Jan 25, 2020 10:21 am

Re: What's bad for our batteries?

Sat Feb 08, 2020 8:37 am

vreihen wrote:
Wed Feb 05, 2020 10:07 am
Depending on who you ask...

Fast charging (DC or 32A Level2)
Discharging to 0%
Charging to 100%
Long-term parking
Charging too frequently
High number of discharge cycles
Charging when hot
Charging when cold
Looking at your car in the wrong way :lol:

My $0.02 is to let the battery management system do the worrying and just enjoy your car, trusting that the BMW engineers have picked the best set of tradeoffs to ensure a long and productive vehicle life.....
Yes, most of these things aren't good for the battery and we should hope the battery management system does a good job. That said, what would be the best practices? Would be good to know the order in which these things are best/worse for the car. I'm thinking discharge to 0 is very bad and charging frequency based on cell phones.

eNate
Posts: 438
Joined: Mon Sep 09, 2019 5:33 pm

Re: What's bad for our batteries?

Sat Feb 08, 2020 2:28 pm

panamamike wrote:
Sat Feb 08, 2020 8:37 am

...what would be the best practices? ... discharge to 0 is very bad and charging frequency
It's not possible to drive the i3 to zero. It holds a substantial reserve. Zero indicated is virtual. Same at 100%.

Frequency of charging is said to have no effect on battery health. One hundred 10% charges has the same degradation as ten 100% charges. Leaving it plugged in won't overcharge it.

The most impactful degradation seems to be frequent DC fast charging.
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